EVALUATION OF LONDON PRIMARY CARE TRUST
MMR CATCH-UP PROGRAMMES
IN RESPONSE TO
CALL OF THE CHIEF MEDICAL OFFICER:
SEPTEMBER 2008 – MAY 2009
Report of the Evaluation Subgroup:
London Childhood Immunisation Steering Group;
Commissioning Support for London
NHS London
Dr Amy Glasswell
Louise Bishop
Dr Graham Fraser
For the Evaluation Subgroup of the London Immunisation Steering Group
Address for correspondence:
The Regional Epidemiologist
Health Protection Agency London Region
7th Floor, Holborn Gate
330 High Holborn
London WC1V 7PP
E-mail:graham.fraser@hpa.org.uk
April 2010
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CONTENTS
Section
Title
Page
Executive Summary
3
Recommendations
7
List of tables, figures and
appendices
9
11
1.
Background
2.
Methods
12
3.
Results
13
4.
Discussion
21
5.
Conclusions
27
Acknowledgements
References
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EXECUTIVE SUMMARY
Background:
Uptake of MMR has decreased steadily in England since 1997, creating a critical
increase in the number of children susceptible to measles. In August 2008 the Chief
Medical Officer noted that modelling projections showed a risk of an epidemic of 30100,000 cases. He called for a nationwide catch-up programme for MMR vaccination
for children of all ages from 13 months to 18 years.
Primary care trusts (PCTs) were charged with implementing the campaign. This
included the identification of eligible children, ensuring invitation for vaccination, and
appropriate follow-up to encourage non-attenders to be vaccinated. In London the
Regional Director of Public Health required PCTs to implement the campaign under
oversight and review of a designated Director of Public Health and the
Commissioning Support for London Immunisation Project Steering Group.
PCTs made summary returns for their programme to the Regional Epidemiologist.
These gave the number of children in their district by birth cohort and MMR
vaccination status, as at 1 September 2008 and 1 May 2009. Summary returns were
received from 29 PCTs. Following detailed review by the Evaluation Sub-Group
(including enquiry back to the PCT) it was considered that returns from 12 remained
sufficiently internally inconsistent to justify exclusion from the analysis. Returns from
the remaining 17 PCTs (21 PCTs for <5yrs age group) were used for this evaluation.
Results and Discussion
(a) effects on vaccine uptake
Overall the summary returns, together with the routine COVER reports, suggest
some significant achievement in raising the vaccination rate for children of primary
schedule age (<5yrs) at the outset of the catch-up programme. The returns report
For this age group at September 2008, there were over 18,000 fewer unvaccinated
and 30,000 more completely vaccinated (‘MMR2’) at the conclusion of the
programme in May 2009 for the 21 PCTs included in this evaluation. These changes
correspond to a decrease from 25% to 19% by May 2009 in unvaccinated children in
children in this age group at September 2008.
However, distinguishing catch-up vaccinations from normal schedule vaccines is not
possible with certainty in this primary schedule age group with this methodology.
These findings were however supported by reports of the routine COVER
programme, which showed a decrease in unvaccinated children aged 5yrs from 20%
to 17% between July-September 2008 and April-June 2009. They are also partly
supported by results from the Department’s Immform data system.
In contrast the reported effects of the programmes on vaccination status of children
above primary schedule age (5-18yrs at the start of the programme) were
substantially less than for the younger groups. For this age group at September
2008, there were 4,900 fewer completely unvaccinated children reported for these
PCTs at May 2009, and 8,300 more completely vaccinated children (‘MMR2’).
Although prevalence calculations are uncertain because of the uncleaned/partially
cleaned denominator data for children of this age in most PCTs, these reported
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vaccinations represent only a small change in the prevalence of unvaccinated
children in the school age group in these PCTs (27.9% to 27.2%).
The present catch-up results among school age children appear significantly less
than those of the ‘Capital Catch-up’ programme among London primary school
children in 2004/05. That programme achieved significant estimated reductions in the
prevalence of children susceptible to measles in those age-groups, and small
reductions in community epidemic risk. The effects of the present programmes on
measles risk reduction among school age children will be somewhat less than that
campaign.
(b) organisational and data issues
PCTs invested considerable effort in supporting the predominantly GP based catchup programmes in the primary schedule vaccine age group. Most instituted local
enhanced services (LES) arrangements for their practitioners, and engaged in
substantial data cleaning exercises, for both numerators and denominators of their
child health databases. In most PCTs general practitioners identified and invited the
children for vaccination; child health departments carried out this function in a few
PCTs.
Sourcing, processing and returning the data requested by the RDPH posed a
significant resource issue for all PCTs, and was problematic for some. Several PCTs
were at various stages of restructuring of their child health information systems
(CHIS), and reported difficulties with providing the returns. A minority of PCTs turned
to ad hoc and systems other than their CHIS to make the returns requested.
Data problems for several London PCTs have been a notable feature of their returns
to the national COVER programme monitoring immunisation uptake, such that
cautionary footnotes have been applied to a number of PCT returns to that
programme. The present evaluation is similarly affected by significant prima facie
data problems with nearly one third of the PCT returns; problems verified or not
resolved by enquiry back to the PCTs.
Good immunisation information systems and effective programmes are interlinked.
Effective PCT child health information systems support vaccine uptake at every step
from parent recall to performance feedback to practices. This evaluation adds to
continuing concerns regarding the critical need for support to PCTs in achieving
sustained improvement in child health information system performance.
Conclusions
The present predominantly general practice based MMR catch-up programme
appears to have achieved significant results among children of primary schedule age
(<5ys). This represents an important investment for the future re reduction in
community measles risk in London. However levels of susceptibility to measles still
remain considerably above European standards in this age group. PCTs must build
on and consolidate the organisational and system gains made, and the evidence of
gradually returning public confidence, to maintain and further increase uptake of the
vaccine in this age group.
The present catch-up has however been less effective in vaccinating children above
primary schedule age (5yrs and above). This group comprises the most significant
contribution to current community measles epidemic risk in London. Given this
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programme outcome, previous modelling projections relating to vulnerability to
epidemics in London remain essentially current.
The reasons for the modest returns from the present mostly general practice based
catch-up programme among school age children should be clarified as a priority. It is
likely that both PCT and GP information systems significantly under-estimate the
number of vaccinated children, and this may partially explain the poor catch-up
response in school age children. Other factors are also likely to be relevant, ranging
from parent/older child perceptions of need through to health service organizational
and system factors.
The most effective methods for catching up MMR vaccination in older (school-age)
children remain elusive. Both the previous ‘Capital Catch-up’ programme and the
present one have their strengths and weaknesses, but neither has been as effective
as hoped in catching up school age children. Further investigations should be
undertaken to identify optimum methods for catch-up interventions among older
children. Emerging experience from these programmes in London, together with
limited evidence from the literature (for other vaccines) and from the HPV vaccine
programme to date, suggest that school based programmes that constitute peer
group experience may be more effective than individual general practice recall in
older children and young adults.
Given the presence of significant numbers of susceptible school children of all ages,
and the relatively modest returns from the present general practice based
interventions in these age groups, attention should be given to implementing ongoing
school based interventions at strategic points of the child’s school experience,
including school-leaving. These need to be supported by appropriate key
performance indicator(s) (KPI) within the NHS performance management framework.
Once children leave school their chance of being vaccinated against these diseases
(including also rubella and mumps) are significantly reduced.
Issues related to data quality and completeness continue to be a significant
constraint for effective monitoring of the level of measles epidemic risk, particularly
among children over the age of five years. The difficulty in obtaining and maintaining
data on the immunisation status of children of all ages up to 18 years remains a
critical issue, which feeds back into decreased effectiveness in service provision. The
development and maintenance of effectively managed and supported child health
information systems evidently remains a critical issue for many primary care trusts in
London.
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RECOMMENDATIONS
In the light of the present findings, it is recommended by the Evaluation Subgroup
that:
1.
Primary Care Trusts should:
a. evaluate the results of their catch-up programmes, with particular
reference to factors underlying the relative failure of the catch-up in
children above schedule age (including child/parent as well as
organisational and system factors)

factors associated with non-response to the catch-up in
children above schedule age, including age, sex, area of
residence, deprivation index;

assessment of the point(s) of relative failure of the catch-up
programme in older children (eg non response to GP invitation,
with-holding of consent, etc)

assessment of attitudes of older children and their parents
towards catch up MMR vaccination
b. plan, implement and evaluate further interventions to effectively catchup school-age children, including settings and methods
complementary to the present programme, based on and adding to
the limited evidence available for effective catch-up programme
design for older children;
c. plan and implement routine systems for identifying the vaccination
status of school-age children at strategic point(s), (eg school entry,
secondary school entry, school leaving), and ensuring completion of
their schedule vaccinations including MMR;
d. review their Child Health Information systems (CHIS), with particular
respect to:

management and financial and skills resource sufficient to
achieve and maintain effective CHIS operation, including
relations with general practices, contiguous PCTs, and
schools (for school vaccination programmes) as data
providers, and audit and analysis of the data

completion of review and cleaning of their databases relating
to the vaccination status of children and young people in their
populations from birth to 18 years of age.
2. Commissioning Support for London/NHS London should:
a. commission audits, applied research and guidelines to support PCTs
in catch-up programme evaluation and intervention planning;
b. require PCTs to achieve a defined quality of immunisation data for
children 0-18 years in their populations by an agreed date;
c. support PCTs in achieving adequate CHIS with dedicated expert and
financial resource;
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d. agree with PCTs London-wide that further interventions
complementary to the present programme will be developed and
implemented;
e. require that routine MMR coverage be measured at school leaving
and negotiate for inclusion of this as a ‘vital sign’ within the KPI
performance management system;
f.
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ensure a continued inter-disciplinary and inter-agency focus within
NHS London/Commissioning Support for London to achieve
immunisation uptake and child health data systems appropriate for a
world class city.
Page 8 of 30
LIST OF TABLES, FIGURES AND APPENDICES
Tables
Table 1. Characteristics of London Primary Care Trust (PCT) catch-up programmes,
2008-09 (n=23 respondents)
Table 2 MMR catch-up London PCTs 2008-09: data from summary returns; cohorts
less than five years at programme outset
Table 3. MMR catch-up London PCTs 2008-09: data from summary returns; cohorts
five years and older at programme outset
Table 4. MMR catch-up London PCTs 2008-09: data from summary returns; all age
cohorts 13 months to 18 years at programme outset
Table 5. Summary of outcomes of London PCT MMR catch-up programmes, 200809: as reported by PCT summary returns, COVER reports, ImmForm system
Figures
Figure 1. Uptake of MMR vaccination by age two, London and England, 1996-2009
Figure 2. Incidence of confirmed cases of measles, London and England & Wales,
January 2007-September 2009
Figure 3. European guidelines for prevention of indigenous measles
Appendices
1. Membership of Evaluation Sub-Group
2. PCT summary return proforma
3. Data sources for and database cleaning conducted in association with the
PCT catch-up programmes, London PCT, as reported June-July 2009
4. PCT summary returns included in evaluation
5. COVER data (5a: MMR uptake at age 2 for London PCTs, July 2008-June
2009 and 5b: MMR uptake at age 5 for London PCTs, July 2008-June
2009)
6. Department of Health ImmForm data: vaccination status, children of and
above primary schedule age, 31 August 2008-30 April 2009 (6a: primary
schedule age and 6b: above primary schedule age)
7. Minimum vaccine coverage of children aged 2-18 years in London
1.
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1. BACKGROUND
Uptake of measles, mumps and rubella vaccine (MMR) has decreased steadily in
England since 1997, creating a critical increase in the number of children susceptible
to measles1-3. In July-September 2008 the uptake of MMR at age 2 for England
overall was 83.4% and 71.5% in London (Figure 1)4.
Measles cases and outbreaks have returned, no longer limited to specific groups
opposed to immunisation (although cases are confined almost exclusively to
unimmunised individuals). Over thirteen hundred cases were confirmed in England in
2008 (664 in London). Many cases are not laboratory tested and remain
unconfirmed5.
Figure 1 - MMR1 coverage at age 2 for London and England:
January 1996-December 2009
100
London
91.1
England
90
% coverage
89.5
87.7
80
80.5
70
60
No England data available betw een July 2005 and June 2006
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Year and quarter
Source: CfI Immunisation department, HPA
In August 2008 the Chief Medical Officer (CMO), noting that modelling projections
showed a risk of a nationwide epidemic of 30-100,000 cases, called for a nationwide
catch-up programme for MMR vaccination for children of all ages from 13 months to
18 years6. The programme was to commence in September 2008, with first priority to
be given to completely unvaccinated children. Other priority groups included partially
immunised children aged 3 years 7 months to 11 years, 12 years to 18 years, and
individuals leaving school to go on to other education establishments.
Primary care trusts (PCTs) were charged with implementing the campaign. This
included the identification of eligible children (in association with general practices
where needed), ensuring invitation for vaccination and appropriate follow-up to
encourage non-attenders to be vaccinated. The Department of Health (DH) made
additional doses of vaccine available, together with information materials and
additional funding.
In London the Regional Director of Public Health (RDPH) required PCTs to
implement the campaign, under oversight and review of a designated Director of
Public Health and the Commissioning Support for London Immunisation Project
Steering Group. The Steering Group implemented an Evaluation Sub-Group
(Appendix 1) chaired by the Regional Epidemiologist. PCTs were required to make
summary returns on the effect of their campaigns as at 1 May 2009 by 1 June 2009.
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2. METHODS
Most primary care trusts in London implemented the programme through general
practices, usually supported by a Local Enhanced Service agreement (LES). A
minority of trusts used supplementary or alternative settings and services to provide
vaccinations. Children eligible for the catch-up were identified by practices and/or
PCT child health departments, and parents or guardians of these children were
contacted individually with an invitation for their child to have the catch-up MMR
vaccination. Trusts facilitated this process through various activities, including
support for or direct identification of eligible children, and cleaning of databases
identifying eligible children and vaccinations given.
Trusts were asked to make a defined summary return (Appendix 2) giving the
number of children in their PCT populations by birth cohort as at 1 September 2008
in the following categories: number of children with history of one (only) MMR
vaccination, of two MMR vaccinations, with no history of MMR vaccination. This
information was also requested for these cohorts as at 1 May 2009. (In addition the
number of children with history of single measles vaccination was requested as at 1
May 2009). (as at 1 September 2008 and 1 May 2009),
Trusts obtained data relating to the number of children in their populations by age
and vaccination category through various means, either singly or in combination,
including the PCT child health information system (CHIS), creation of a bespoke
database from data downloaded from GP information systems, interrogation of GP
systems where their software suppliers were able to extract and submit bulk data to
the Department of Health ImmForm system website7. In addition PCTs returned a
questionnaire covering key aspects of their catch-up programme to assist
interpretation of their summary returns.
PCT returns were reviewed by the Evaluation Sub-Group for completeness, apparent
transcription errors and prima facie internal consistency of information, by age cohort
and for the return overall. PCTs were invited to clarify apparent problems and
inconsistencies in the data. Where significant problems with the data remained
unresolved, the return was excluded from the present analysis.
The remaining returns were included in the evaluation. Reports were analysed for the
numbers of children in their cohorts with a history of no, one only and two MMR
vaccinations as at 1 September 2008 and 1 May 2009, and changes in these
numbers between these two dates. Total cohorts were calculated as the sum of
children reported as having received 0, 1 or 2 MMR vaccines. Prevalences of
children completely unvaccinated and with a history of complete vaccination were
calculated from the total reported cohorts. Changes in the total reported cohorts were
also assessed, and compared with recent cohorts reported to the COVER
programme4). Analyses relating to cohorts of children of primary schedule age (under
5 years at the outset of the programme 1 September 2008) were summarised
separately from cohorts of older children (5 years and over).
PCT summary returns for children of primary schedule age (<5yrs) were also crossreferenced against reports made to the COVER programme during the catch-up
period, and data obtained by the Department of Health available through the
ImmForm website.
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3. RESULTS
3.1
Summary information relating to catch-up programmes, data
sources and database cleaning
Twenty-three of the 31 London PCTs returned covering questionnaires outlining their
catch-up programme characteristics, data sources and data cleaning programmes.
Eligible children were identified by general practices in 16/23 PCTs, by PCTs
themselves in three cases and by other means in four PCTs. Twenty-two PCTs
confirmed that parents were contacted individually; by practices in 17 PCTs, by trusts
themselves in three cases, and by other means in three PCTs. A Local Enhanced
Service agreement (LES) was established by 21 of 22 PCTs responding to this
question (Table 1).
Table 1 – Characteristics* of London PCT catch-up programmes, 2008-09
(n=23)
Programme Element
Identification of children eligible for the catch-up
programme
Contact of parent/caregivers of eligible children
with invitation for immunisation
Public relations strategies employed
Arrangements for funding for children above
primary schedule age
Method or Source
By Practices
By PCTs
Other
By practices
By PCTs
Other
Posters
Leaflets
Local media
Press release
Letter drop
Telephone follow-up
Web
LSMU
Not stated
LES
Immunisation support team created
Task force created
None cited
Number of PCTs
16
3
4
17
3
3
6
4
4
2
2
2
2
1
6
21
1
1
1
*more than one response permitted for items 2 , 3 and 4.
Sixteen of the 23 responding PCTs used their child health information systems
(CHIS) as the data source for their summary return. Seven PCTs used other sources,
including EMIS Web, Health Intelligence and data extraction from GP systems.
Nearly all (20/23) PCTs reported data cleaning activity associated with the
programme in relation to information on children of primary schedule age (<5yrs):18
and 17 PCTs reported this activity as more than 50% complete in relation to
numerator and denominator data respectively for this age group. Data cleaning for
numerator and denominator information relating to older children (>5yrs) was less
frequent, and reported in progress by 11 and 13 PCTs respectively: only seven and
10 PCTs reported this activity more than 50% complete (Appendix 3).
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3.2
Summary returns of child vaccination status in PCT populations:
data issues; exclusion of some returns from this evaluation
Summary returns were received from 29 of 31 PCTs. Two PCTs made no return; one
indicated data would be available outside the time-frame of this evaluation. Three
PCTs returned no or incomplete data for children above primary schedule age.
Several PCTs were at various stages of restructuring of their child health information
systems, and reported difficulties with providing the returns.
Following detailed review by the Evaluation Sub-Group, 12 PCTs were asked to
clarify aspects of their returns. Nine PCTs responded with varying explanations and
comment. Four PCTs submitted substantially revised data and three made minor
alterations to their return. Following further review it was considered that returns
from 12 PCTs (8 PCTs for data relating to primary schedule age children) remained
sufficiently internally inconsistent to justify exclusion from the analysis, and that their
inclusion would materially affect an accurate estimation of the cumulative effect of the
programmes at regional level. Returns from the remaining 17 PCTs (21 PCTs for
<5yrs age group) were included in the analysis (Appendix 4).
Twelve of the PCTs included in the evaluation made returns with ‘MMR1’ numbers
defined as ‘at least one MMR’ (as per routine COVER returns). These returns were
recalculated as per the report specification (MMR1 = one MMR received) and the
adjustments verified with the PCTs.
3.3
Changes in numbers of unvaccinated and vaccinated children
before and after the catch-up programme
A summary of the returns of the remaining PCTs are given in Tables 2-4 for children
of primary schedule age (<5yrs; 19 PCTs), above primary schedule age (>5yrs; 16
PCTs) and for all age groups (16 PCTs).
(a) Children of primary schedule age (<5 yrs as at 1 September 2008):
For children in this age group identified at 1 September 2008, there were 30,077
children in the 21 PCTs with completed MMR vaccination schedules (MMR2) at 1
May 2009; 18,697 fewer children were identified as completely unvaccinated
(MMR0). This corresponded to a reported decrease in the prevalence of completely
unvaccinated children in this group in these PCTs from 25.3% to 19.2%, and an
increase in completely vaccinated (MMR2) children from 21.6% to 31.7%.
There were 12,662 fewer children identified as having received one dose of MMR as
at May 2009; this figure reflects a balance between children receiving their first and
second dose of MMR during the period, consistent with more second than first doses
of vaccine being administered. Although total cohort numbers between September
2008 and May 2009 varied somewhat for individual PCTs, reportedly related to data
cleaning activity, these variations were not excessive, and minimal for the 21 PCTs
overall (Table 2).
(b) Children above primary schedule age (5yrs of age and older as at 1
September 2008)
Changes in vaccination status reported by the 17 PCTs for older children were much
smaller than for the <5yr groups. Among children identified 5-18yrs at 1 September
2008, there were 4,994 fewer completely unvaccinated (MMR0) children reported for
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these PCTs by May 2009, and 8,297 more completely vaccinated (MMR2) children.
This represented a change in the prevalence of completely unvaccinated children for
this group in these PCTs from 27.9% to 27.2%. Total cohort numbers varied
somewhat by PCT but overall they were stable for these PCTs (Table 3).
c) Children of all ages (13 months to 18 years at 1 September 2008)
For the 17 PCTs which returned accepted data for all age groups, the number of
children reported as completely unvaccinated with MMR at 1 September 2008
decreased by 20,089 during the period. This corresponded to an estimated decrease
in the prevalence of completely unvaccinated children of all age groups (13 months
to 18 years) from 27.5% to 25.4%.
The number of children reported as completely vaccinated increased by 30,152
between September 2008 and May 2009, an estimated increase in the prevalence of
completely vaccinated children from 42.1% to 45.3% (Table 4).
It should be noted that these overall reported results represent a combination routine
vaccine schedule and catch up vaccination activity.
3.4
Single vaccine administration
A significant number of children (5,577) were reported as having a history of
immunisation with single measles vaccine. Most of these were reported in the 5yrs
and above age-group (4,320) (Tables 2-4).
3.5
Estimation of total vaccinations given by the catch-up
programmes across London (children above primary schedule
age)
Assuming the reported results from the 17 PCTs included in this evaluation can be
extrapolated to the London level, the following approximate estimates are obtained:
For children above primary schedule age (5yrs and above at 1 September 2008) the
number of completely unvaccinated children is estimated to have decreased by 9,188
over the period, and the number of completely vaccinated children (‘MMR2’)
increased by 15,606.
This estimation is not attempted for children <5yrs as the catch-up vaccinations
cannot be effectively distinguished from routine vaccine schedule activity.
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Table 2 - MMR catch-up London PCTs 2008-09: data from summary returns; cohorts less than five years at programme outset
% No
% No
Cohort
Total
Total
Single
No MMR
2 MMR
1 MMR
% MMR2 % MMR2
MMR
MMR
Cohort Absolute
Cohort
2 MMR Absolute No MMR No MMR Absolute Vaccine
1 MMR Absolute 2 MMR
1 MMR
Sep 2008 May 2009 Increase Sep 2008 May 2009 Increase Sept 2008 May 2009 Change May 2009 Sept 2008 May 2009 Change Sep 2008 May 2009 Sep 2008 May 2009
PCT
Barking & Dagenham*
Barnet*
Bromley
Camden
City & Hackney Teaching*
Croydon*
Ealing*
Enfield*
Greenwich Teaching
Hammersmith & Fulham*
Havering*
Hillingdon
Islington*
Kensington & Chelsea
Kingston
Lambeth
Redbridge*
Tower Hamlets
Waltham Forest*
Wandsworth*
Westminster
LONDON (21/31 PCTs)
7115
9776
4373
7047
8327
11429
12877
8809
7979
5910
6045
8438
5437
5161
942
8467
9013
7029
10151
10740
5072
160137
6829
9265
5417
7655
8100
10287
11233
7697
6448
5586
5485
6648
5225
5471
655
6174
8170
6562
9233
10867
4468
147475
-286
-511
1044
608
-227
-1142
-1644
-1112
-1531
-324
-560
-1790
-212
310
-287
-2293
-843
-467
-918
127
-604
-12662
2255
3126
7956
1499
2528
3807
3501
3252
3066
1289
2551
3374
1106
1093
6408
4760
3308
3261
3055
2771
1226
65192
3073
4295
8164
2398
3259
6056
6397
5018
5716
2182
3604
5724
1695
1748
6897
7909
4982
5091
4602
3599
2860
95269
*interpreted as at least 1 MMR
data used for <5 years only
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818
1169
208
899
731
2249
2896
1766
2650
893
1053
2350
589
655
489
3149
1674
1830
1547
828
1634
30077
8179
3302
3073
3684
6652
3944
4682
2971
4816
2050
7031
3419
2364
1317
835
4960
4477
1793
2247
3147
1560
76503
6829
2644
2040
2177
6094
2704
3430
2317
3682
1654
5485
1541
1966
996
633
4026
3646
1399
1618
2192
733
57806
-1350
-658
-1033
-1507
-558
-1240
-1252
-654
-1134
-396
-1546
-1878
-398
-321
-202
-934
-831
-394
-629
-955
-827
-18697
42
81
0
0
47
85
440
0
122
221
185
295
0
0
0
0
255
27
0
0
1800
17549
16204
15402
12230
17507
19180
21060
15032
15861
9249
15627
15231
8907
7571
8185
18187
16798
12083
15453
16658
7858
301832
16731
16204
15621
12230
17453
19047
21060
15032
15846
9422
14574
13913
8886
8215
8185
18109
16798
13052
15453
16658
8061
300550
-818
0
219
0
-54
-133
0
0
-15
173
-1053
-1318
-21
644
0
-78
0
969
0
0
203
-1282
47%
20%
20%
57%
38%
21%
22%
20%
30%
22%
45%
22%
27%
17%
10%
27%
27%
15%
15%
19%
20%
26%
41%
16%
13%
18%
35%
14%
16%
15%
23%
18%
38%
11%
22%
12%
8%
22%
22%
11%
10%
13%
9%
18%
13%
19%
52%
12%
14%
20%
17%
22%
19%
14%
16%
22%
12%
14%
78%
26%
20%
27%
20%
17%
16%
22%
18%
27%
52%
20%
19%
32%
30%
33%
36%
23%
25%
41%
19%
21%
84%
44%
30%
39%
30%
22%
35%
32%
Table 3 - MMR catch-up London PCTs 2008-09: data from summary returns; cohorts five years and older at programme outset
1 MMR
2 MMR
No MMR
Single
Total
Total
Cohort
% No
% No
1 MMR
1 MMR Absolute 2 MMR
2 MMR Absolute No MMR No MMR Absolute Vaccine
Cohort
Cohort Absolute
MMR
MMR
% MMR2 % MMR2
Sep 2008 May 2009 Increase Sep 2008 May 2009 Increase Sept 2008 May 2009 Change May 2009 Sept 2008 May 2009 Change Sep 2008 May 2009 Sep 2008 May 2009
PCT
Barking & Dagenham*
Barnet*
Bromley
Camden
City & Hackney Teaching*
Croydon*
Ealing*
Enfield*
Greenwich Teaching
Havering*
Islington*
Kensington & Chelsea
Kingston
Redbridge*
Waltham Forest*
Wandsworth*
Westminster
LONDON (17/31 PCTs)
7446
15352
12546
574
13794
12745
9947
3518
14488
7101
6541
6793
3146
10687
5424
23879
5353
159334
7372
15336
12845
622
13817
12309
9689
3121
14449
6939
6504
6808
2910
10640
5292
23841
4302
156796
-74
-16
299
48
23
-436
-258
-397
-39
-162
-37
15
-236
-47
-132
-38
-1051
-2538
22284
23192
28545
3068
23577
36173
37658
13510
17134
29401
14604
4610
19745
30212
30339
4928
9007
347987
22414
23318
28410
3216
23675
36916
38198
14097
17512
29693
14670
4698
20049
30650
30797
5303
12668
356284
*interpreted as at least 1 MMR
116097147
Page 17 of 30
130
126
-135
148
98
743
540
587
378
292
66
88
304
438
458
375
3661
8297
7556
12292
8239
32974
16795
15631
13877
26046
15126
7363
3959
1683
1537
19679
6074
4777
3402
197010
7371
12182
8026
32778
16648
15153
13595
25856
14591
6941
3930
1663
1469
19288
5748
4440
2337
192016
-185
-110
-213
-196
-147
-478
-282
-190
-535
-422
-29
-20
-68
-391
-326
-337
-1065
-4994
177
481
0
0
177
220
1992
0
287
506
0
0
0
480
0
0
4320
37286
50836
49330
36616
54166
64549
61482
43074
46748
43865
25104
13086
24428
60578
41837
33584
17762
704331
37157
50836
49281
36616
54140
64378
61482
43074
46552
43573
25104
13169
24428
60578
41837
33584
19307
705096
-129
0
-49
0
-26
-171
0
0
-196
-292
0
83
0
0
0
0
1545
765
20%
24%
17%
75%
31%
24%
23%
60%
32%
17%
16%
13%
6%
32%
15%
14%
19%
26%
20%
24%
16%
90%
31%
24%
22%
60%
31%
16%
16%
13%
6%
32%
14%
13%
12%
26%
60%
46%
58%
8%
44%
56%
61%
31%
37%
67%
58%
35%
81%
50%
73%
15%
51%
49%
60%
46%
58%
9%
44%
57%
62%
33%
38%
68%
58%
36%
82%
51%
74%
16%
66%
50%
Table 4 - MMR catch-up London PCTs 2008-09: data from summary returns;
all age cohorts 13 months to 18 years at programme outset
1 MMR
2 MMR
No MMR
Single
Total
Total
Cohort
% No
% No
1 MMR
1 MMR Absolute 2 MMR
2 MMR Absolute No MMR No MMR Absolute Vaccine
Cohort
Cohort Absolute
MMR
MMR
% MMR2 % MMR2
Sep 2008 May 2009 Increase Sep 2008 May 2009 Increase Sept 2008 May 2009 Change May 2009 Sept 2008 May 2009 Change Sep 2008 May 2009 Sep 2008 May 2009
PCT
Barking & Dagenham*
14561
14201
Barnet*
25128
24601
Bromley
16919
18262
Camden
7621
8277
City & Hackney Teaching*
22121
21917
Croydon*
24174
22596
Ealing*
22824
20922
Enfield*
12327
10818
Greenwich Teaching
22467
20897
Havering*
13146
12424
Islington*
11978
11729
Kensington & Chelsea
11954
12279
Kingston
4088
3565
Redbridge*
19700
18810
Waltham Forest*
15575
14525
Wandsworth*
34619
34708
Westminster
10425
8770
LONDON (17/31 PCTs)
289627
279301
*interpreted as at least 1 MMR
116097147
-360
-527
1343
656
-204
-1578
-1902
-1509
-1570
-722
-249
325
-523
-890
-1050
89
-1655
-10326
24539
26318
36501
4567
26105
39980
41159
16762
20200
31952
15710
5703
26153
33520
33394
7699
10233
400495
25487
27613
36574
5614
26934
42972
44595
19115
23228
33297
16365
6446
26946
35632
35399
8902
15528
430647
Page 18 of 30
948
1295
73
1047
829
2992
3436
2353
3028
1345
655
743
793
2112
2005
1203
5295
30152
15735
15594
11312
36658
23447
19575
18559
29017
19942
14394
6323
3000
2372
24156
8321
7924
4962
261291
14200
14826
10066
34955
22742
17857
17025
28173
18273
12426
5896
2659
2102
22934
7366
6632
3070
241202
-1535
-768
-1246
-1703
-705
-1718
-1534
-844
-1669
-1968
-427
-341
-270
-1222
-955
-1292
-1892
-20089
219
562
0
0
224
305
2432
0
409
691
0
0
0
735
0
0
0
5577
54835
67040
64732
48846
71673
83729
82542
58106
62609
59492
34011
20657
32613
77376
57290
50242
25620
951413
53888
67040
64902
48846
71593
83425
82542
58106
62398
58147
33990
21384
32613
77376
57290
50242
27368
951150
-947
0
170
0
-80
-304
0
0
-211
-1345
-21
727
0
0
0
0
1748
-263
29%
23%
17%
75%
33%
23%
22%
50%
32%
24%
19%
15%
7%
31%
15%
16%
19%
26%
26%
22%
16%
72%
32%
21%
21%
48%
29%
21%
17%
12%
6%
30%
13%
13%
11%
24%
45%
39%
56%
9%
36%
48%
50%
29%
32%
54%
46%
28%
80%
43%
58%
15%
40%
42%
47%
41%
56%
11%
38%
52%
54%
33%
37%
57%
48%
30%
83%
46%
62%
18%
57%
45%
3.6
Other data sources relating to the catch-up programmes
Information from the PCT summary returns was compared with information obtained
from the ongoing quarterly COVER reports8 and the Department’s ImmForm system7:
(a) The ‘COVER’ programme
PCT routine quarterly reports to the national COVER programme for monitoring
routine primary schedule vaccine uptake prior to and during the period of the catchup programmes are summarised in Appendix 5.
The prevalence of children reported as completely unvaccinated by age 5 in London
overall decreased from 20.6% in July-September 2008 to 17.4 % in April-June 2009,
a decrease of 3.2%. (Equivalent figures for England were 11.7% and 10.0%, a
decrease of 1.7%).
Overall the prevalence of children reported as vaccinated with MMR by age 2 in
London rose from 71.5% in July-September 2008 to 76.8% in April-June 2009, an
increase of 5.3%. (Equivalent figures for England overall rose from 83.4% to 86.3%,
an increase of 2.9% over the same period).
The results from PCT summary returns and for the closest comparable COVER
return are summarized in Table 5. For most PCTs the results are reasonably
comparable; generally the change in COVER data is somewhat less than in the
evaluation returns.
It should be noted however that the returns are not for exactly the same period, the
COVER returns include all London PCTs, and that some PCTs used data sources
other than the CHIS for their catch-up evaluation return. COVER returns are also
report from moving cohorts (vaccinations received by children aged 5 at each report)
cf the focus on the September 2008 cohort in the evaluation report. In addition,
catch-up vaccinations given after the second year of life will take variable periods of
time (depending on age given) to be reflected in the routine COVER reports (at age
5).
(b) Department of Health ImmForm System
This information system commissioned by the Department of Health extracted data
from compatible general practice information systems relating to MMR vaccinations
given during the catch-up programme period from 31 August 2008 to 30 April 2009.
As expected, given partial and varying coverage of practices, vaccination numbers
for children of primary schedule age reported via the ImmForm system were
substantially less than those reported on the summary returns for most PCTs; for a
small number of PCTs, ImmForm returns greatly exceeded the summary returns. For
children above primary schedule age, the ImmForm returns for the change in
numbers of completely vaccinated children (MMR2) greatly exceeded the numbers
reported by PCTs through the summary returns. This was reflected in a large
unexplained increase in the total cohort size for these older children (not seen for
PCT the summary returns) (Appendix 6).
However, changes in prevalence of vaccination status reported by ImmForm were
broadly consistent with those obtained from the PCT summary returns and COVER
reports. The prevalence of unvaccinated children <5 yrs was reported as unchanged
116097147
Page 19 of 30
between September 2008 and May 2009, but the prevalence of completely
vaccinated (MMR2) children increased from 26% to 31%. In the older (>5yrs) group,
unvaccinated prevalence decreased from 25% to 22%, and completely vaccinated
prevalence increased from 54% to 59% (Appendix 6).
Table 5 - Summary of outcomes of London PCTs MMR catch-up programmes,
2008-09; as reported by PCT summary returns, COVER reports and ImmForm
System
Change in number
of unvaccinated
(MMR0) children
(Sep 08-May 09)
from data returns
<5 years (schedule age)*
>5 years (above schedule age)†
Prevalence of
Change in
unvaccinated
number of fully
children
vaccinated
(MMR0) from
(MMR2) children
data returns
(Sep 08-May 09)
from data returns
-18697
-4994
Sep 08 May 09
26%
18%
26%
26%
30077
8297
Prevalence of
unvaccinated
children (MMR0)
from ImmForm
data ‡
Prevalence of
Prevalence of fully
fully
vaccinated
vaccinated
children (MMR2)
children
from ImmForm
(MMR2) from
data ‡
data returns
Sep 08
19%
25%
Sep 08 May 09 Sep 08
22%
32%
27%
49%
50%
54%
May 09
18%
22%
May 09
33%
59%
Prevalence of fully
vaccinated children
after 5 years from
COVER data (MMR2)§
Jul-Sep 08 Apr-Jun 09
n/a
n/a
58.4%
69.0%
*PCT data from 21 trusts
†PCT data from 17 trusts
‡Department of Health ImmForm system [available at http://www.immform.dh.gov.uk]7
§COVER data [available at http://www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1204031522581]
3.7
Measles epidemiology
The incidence of confirmed cases of measles in London and England 2007-09 is
summarised in Figure 2. Measles incidence in London has declined in the past year,
while continuing unchanged overall in the rest of England and Wales before a decline
during the summer3.
Figure 2 - Incidence of confirmed cases of measles, London versus rest
England & Wales, January 2007-December 2009
200
150
100
50
London
Rest E&W
Source: CfI Immunisation Department, HPA [available online
http://www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1191942172799]
116097147
Page 20 of 30
ov
-0
9
N
Se
p09
Ju
l-0
9
09
09
Month of onset
M
ay
-
M
ar
-
Ja
n09
ov
-0
8
N
Se
p08
Ju
l-0
8
08
M
ay
-
08
M
ar
-
Ja
n08
ov
-0
7
N
Se
p07
Ju
l-0
7
07
M
ay
-
M
ar
-
07
0
Ja
n07
Number of confirmed cases
250
4. DISCUSSION
4.1
Evaluation of programme effectiveness
PCTs evidently invested considerable effort supporting this predominantly GP-based
catch-up programme. Most instituted a Local Enhanced Service (LES) agreement for
their practitioners and engaged in substantial data cleaning exercises, both for
numerators and denominators of their child health databases. In most PCTs general
practitioners identified and invited the children for vaccination; child health
departments carried out this function in a few PCTs.
(a) children of primary vaccine schedule age (13 months – 4 years)
Overall the summary returns, together with the routine COVER reports, suggest
significant achievement in raising the vaccination rate for children of primary
schedule age (13 months - 5.0 yrs) at the outset of the catch-up programme. The
returns report over 18,000 fewer unvaccinated and 30,000 more completely
vaccinated (MMR2) children in this group at September 2008 by May 2009 for the 21
PCTs included in this evaluation. This represents a decrease from 25% to 19% in
unvaccinated children in children of these ages as at 1 September 2008 by May
2009. It is unlikely that data cleaning activity in the PCTs is a substantial contributor
to this change as in most cases reports relating to vaccination status at September
2008 and May 2009 were generated at the same point in time.
These findings for children of primary schedule age cannot however definitively
separate catch-up from routine schedule vaccinations given during the period.
However COVER returns (for all London PCTs) also report a decrease in
unvaccinated children at age 5 from 20.6% to 17.4 % between July-September 2008
and April-June 2009. As COVER reports compare vaccination status for the
populations aged 5 at different times, this decrease does suggest achievement of
some significant catch-up activity over and above routine schedule activity at preprogramme levels. This change in the number of unvaccinated <5yrs children was
not supported by the ImmForm system data, although this data source reported a
significant increase in completely vaccinated children in this age group.
These estimates for unvaccinated children under 5 years are still some distance from
the 15% prevalence for susceptibility required by European guidelines (Figure
3)9.,but the gap appears to have been significantly reduced.
(b) children above primary schedule age (5-18 years)
In contrast the reported effects of the programmes on the vaccination status of
children above primary schedule age (5yrs and older at the start of the programme)
were substantially less than for the younger groups. There were 5,000 fewer
completely unvaccinated children reported in this group for these 17 PCTs by May
2009 and 8,300 more completely vaccinated children (MMR2). Although prevalence
calculations are uncertain because of the uncleaned/partially cleaned denominator
data for children of this age in most PCTs, the reported vaccinations represent a
change in the prevalence of completely unvaccinated children in this group in these
PCTs between September 2008 and May 2009 from 27.9% to 27.2%.
116097147
Page 21 of 30
Figure 3 - European targets for elimination of indigenous measles by 2010
15%
% susceptible
10%
5%
0%
0-4
5-9
10-14
15-19
20+
Age group
Source: Ramsay, M., A strategic framework for the elimination of measles in the European Region, 1999, WHO 9
If this is extrapolated to London as a whole (assuming similar performance by PCTs
not included in the evaluation) the catch-up programme may have reduced
unvaccinated children in this older age group by 9,100, and increased the number
of completely vaccinated children by 15,100. This result may be compared with
vaccinations given during the Capital Catch–up campaign of 2004/05, to 16,500
(primary school age only) children with no history of MMR vaccination, and 40,000
children overall.
The ImmForm system reported a somewhat larger decrease in unvaccinated children
in the five and over age group from 25% to 22% (for all London PCTs).
While the benefits to the vaccinated individual children above primary schedule age
form the programme are important, the outcome of the programme in ‘catching up’
MMR vaccination among older children for the purpose of significant reduction of
epidemic risk has not been achieved.
The reasons for the low response to the catch-up programme in older children are
not known to the Evaluation Group. Understanding the reasons for this is seen as a
priority. There are likely to be information, system and parent/child factors involved:
First it is likely that that the numbers of unvaccinated children may be significantly
less than estimated by both PCT CHIS and GP information systems. It is likely that
results from both the PCT summary returns and the ImmForm system have
significantly underestimated the prevalence of vaccinated older children (>5yrs) in
these PCT districts. Historical measurements of one dose coverage for these cohorts
by the COVER programme when they were 2 and 5 years of age, ranged from 7387%. This corresponds to an average prevalence of unvaccinated children in these
present school age cohorts of 17%, about 30% lower than the estimates given by
both PCT returns and the ImmForm system (Appendix 7).
116097147
Page 22 of 30
In addition, it is possible that significant numbers of school age children vaccinated
through the Capital Catch-up programme of 2004-05 may not have had their
vaccinations entered on to their PCT CHIS. This programme reported the vaccination
of 40,000 children through bespoke summary returns from schools; while uploading
this data to PCT child health databases (or to GP information systems) was
encouraged, it was not formally required or universally completed.
Finally, a
relatively small number of single measles vaccinations (about 4,000 vaccinations in
the age 5-17 cohorts) were reported by a number of PCTs10. It is not clear how this
data relates to the CHIS or GP records, and numbers are not large in the context of
overall cohort populations, but this may also have made a small contribution to an
over-estimation of numbers of school age children eligible for the catch-up11.
Second, it is likely that system and parent/child factors were also important in the
modest response for older children to the present programmes. Lower response
rates may relate to less perceived need for the vaccine by parents of older children,
and the children themselves. Reduced access to these children, in terms of both
greater likelihood of incorrect address details in older databases, and fewer
opportunistic occasions for vaccination, may also have been significant. Some PCTs
may have elected to concentrate their efforts on primary schedule age children. In
some cases there may have been problems with recording and transferring
vaccination data for older children to the PCT, or in registering and reporting this data
by the PCT (this not being a routine ‘COVER’ procedure).
The effects of these factors in different PCTs are not known to the evaluators and
they should be examined by individual PCTs as part of their own programme
evaluations. Some audit/applied research should also be commissioned to elucidate
the relative importance of the various factors underlying this modest programme
outcome in older children.
4.2
Epidemic risk and measles epidemiology
Reductions in measles epidemic risk in London as a result of the present catch-up
results among school-age children are significantly less than those of the ‘Capital
Catch-up’ programme among London primary school children in 2004-0512. That
programme achieved estimated reductions in susceptibility to measles of 1-2% in
those age-groups, and small reductions in estimates of community epidemic risk: the
effects of the present programmes on measles risk reduction will be somewhat less
than that campaign.
Measles incidence in London has declined in the past year, while continuing
unchanged overall in the rest of England and Wales until a recent decline in the
summer. However, the decline in incidence in London antedates the present catchup programme, and even peak incidence periods in recent years represent incidence
much lower than predicted as possible by modelling based on cohort susceptibility to
measles (or by the epidemic experience of other European countries). There is also
an indirect connection between population susceptibility and the epidemiology of
measles cases: actual outbreaks depending on the introduction of infected cases to
susceptible communities/social networks.
For these reasons the reduction in measles incidence in recent months cannot be
attributed to the catch-up programme with any certainty. However, the present
programmes provide further evidence of significant under-estimation of actual
vaccination prevalences by PCT and GP information systems, and that some
adjustment for this to the size of epidemic risk in London as described by Choi et al
116097147
Page 23 of 30
(2008) is appropriate1. It should be noted that the epidemic estimates described by
Choi and colleagues include adjustments for probable under-reporting of
vaccinations by the COVER programme.
4.3
Effective catch-up methods
On a broader front, the most effective methods for catching up MMR vaccination
among children above primary schedule age remain elusive. The previous ‘Capital
Catch-up’ programme was entirely primary school based and universal in approach,
with respect to both programme invitations/confirmation of vaccine history and the
administration of vaccine by NHS staff on school premises. This programme was
estimated to have identified 25-30% of eligible primary school age children, and
vaccinated 70% of those identified. Approximately 40,000 primary school age
children were vaccinated by that programme, including 16,000 children previously
unvaccinated (or with unknown vaccination history)12.
This considerably exceeds the results to date from the present general practice
based programme for primary and secondary school age children combined. As
noted above, the previous programme may have had a significant effect on reducing
the number of children (now approximately 9-15 years) eligible for the present catchup programmes, without data on their altered vaccination status always being
available to either PCTs or GPs. Notwithstanding this, and noting a clear field for the
current programme among 5-8 year olds, it appears that the present catch-up
programme has been considerably less effective than the previous school-based
one.
However, the approach to consent and setting outside of general practice created
significant difficulties in administering the Capital Catch-up programme, and rates of
consent withheld by parents were considerable, particularly for younger children of
primary school age10;12;13. Asking all parents to verify their child’s immunisation
history may also have been relatively inefficient and in practice NHS staff often
attempted to verify vaccination status through CHIS records in addition to parental
information given.
It is apparent from the experience of both programmes, that effective means for
intervening at a population level to ‘catch up’ MMR vaccination among school age
children remain uncertain. Identifying effective programme designs for catch up
vaccine programmes in older children should be a priority. Emerging experience from
these programmes in London, together with limited evidence from the literature (for
other vaccines) and from the HPV vaccine programme to date, suggest that school
based programmes that constitute peer group experience may be more effective than
individual general practice recall in older children and young adults.
4.3
Data issues
Sourcing, processing and returning the data requested by the RDPH posed a
significant resource issue for all PCTs and was problematic for some. Several PCTs
were at various stages of restructuring of their child health information systems and
reported difficulties with providing the returns, although nearly all (29/31) did so. A
significant minority of PCTs turned to ad hoc or other systems than their CHIS to
make the returns requested.
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Data problems for several London PCTs have been a notable feature of their returns
to the national COVER programme monitoring immunisation uptake, such that
cautionary footnotes have been applied to a number of PCT returns to that
programme. The present evaluation is similarly affected by significant prima facie
problems with nearly half of the PCT returns; problems verified or not resolved by
enquiry back to the PCTs.
Problems manifested themselves primarily as internal inconsistencies within the
summary returns. In a minority of cases data issues were effectively addressed
(through submission of a significantly altered dataset in two cases). In most cases
PCTs indicated they could not account for or address the data issues raised. These
unresolved data difficulties required the evaluation to be limited to PCT returns that
were considered by an expert subgroup to be reasonably internally consistent and to
have surface plausibility (including consistency with known cohort sizes, absence of
unexplained variations in cohort sizes).
Good immunisation information systems and effective immunisation programmes are
interlinked. Effective PCT child health information systems support vaccine uptake at
every step from parent recall to performance feedback to practices. This evaluation
adds to continuing concerns regarding the critical need for support to PCT Child
Health Departments in improving information system performance relating to
vaccination status of children within their populations14-16.
Appraisal of the results of the catch-up in London is limited and made difficult by the
data difficulties described above. Review of information from related sources (the
COVER programme and the Department’s ImmForm system) was used to triangulate
an appraisal of overall programme effectiveness. The latter are separate systems for
attempting to procure the same vaccine status information. With some exceptions,
the three data systems gave similar views of the prevalence and trends for
vaccination status of the children in the PCTs under study. It is accepted that COVER
returns were also problematic in several instances, but their routine and ongoing
nature give a degree of certainty to observed trends in coverage (compared with a
one-off bespoke report).
In estimating vaccinations given by the programmes overall, the results reported by
the 16/19 PCTs included in the evaluation were extrapolated for the London
population on the assumption that results in the excluded PCTs were equivalent. It is
possible this may give an over-estimate for the vaccinations achieved by the
programmes for London as a whole.
The ImmForm system is characterized by contribution from varying proportions of
general practices in the PCTs, and for most trusts there was little discernible relation
between data relating to vaccines given according to ImmForm data, and the PCT
summary return or COVER data. ImmForm data for vaccination numbers for cohorts
of primary schedule age (<5 years) were generally much lower than for summary
return or COVER data. This is presumed to reflect both the limited number of GP
systems able to provide data to the ImmForm system and data coding problems
impeding extraction of vaccination data. For older cohorts, there was an unexplained
increase in reported numbers of MMR2 children, much greater than that reported by
the summary returns or COVER, along with a parallel increase in reported cohort
size at the end of the catch-up programme.
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5. CONCLUSIONS
The present predominantly general practice based MMR catch-up programme
appears to have achieved some significant results among children of primary
schedule age (<5ys). This represents an important investment for the future re
reduction in community measles risk in London. However levels of susceptibility to
measles still remain considerably above European guidelines. PCTs must build on
and consolidate the organisational and system gains made, and the evidence of
gradually returning public confidence, to maintain and further increase uptake of the
vaccine in this age group.
The present catch-up has however been less effective in vaccinating children above
primary schedule age (5-18yrs). This group comprises the most significant
contribution to current community measles epidemic risk in London. Given this
programme outcome, previous modelling projections relating to vulnerability to
epidemics in London remain essentially current.
The reasons for the modest returns from the present mostly general practice based
catch-up programme among school age children should be clarified as a priority. It is
likely that both PCT and GP information systems significantly under-estimate the
number of vaccinated children, and this may partially explain the poor catch-up
response in school age children. However other factors are also likely to be
important, ranging from parent/older child perceptions of need, through to health
service organisational and system factors.
Given the presence of significant numbers of susceptible school children of all ages,
and the relatively modest returns from the present general practice based
interventions in these age groups, attention should be given to implementing ongoing
school based interventions at strategic points of the child’s school experience,
including school-leaving. The latter should be supported by negotiation of an
appropriate KPI within the performance management system17;18. Once children
leave school their chance of being vaccinated against these diseases (including also
rubella and mumps) are significantly reduced.
The most effective methods for catching up MMR vaccination in older (school-age)
children remain elusive. Both the previous ‘Capital Catch-up’ programme and the
present one have their strengths and weaknesses, but neither has been as effective
as hoped in catching up school age children. Further investigations should be
undertaken to identify effective methods for catch-up interventions among older
children. Emerging experience from these programmes in London, together with
limited evidence from the literature (for other vaccines) and from the HPV vaccine
programme to date, suggest that school based programmes that constitute peer
group experience may be more effective than individual general practice recall in
older children and young adults.
Issues related to data quality and completeness continue to be a significant
constraint for effective monitoring of the level of measles epidemic risk, particularly
among children over the age of 5yrs. The difficulty in obtaining and maintaining data
on the immunisation status of children of all ages up to 18 years remains a critical
issue, which feeds back into decreased effectiveness in service provision. The
development and maintenance of effectively managed and supported child health
information systems evidently remains a critical issue for many primary care trusts in
London.
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ACKNOWLEDGEMENTS
We thank the child health department and other staff from the London Primary Care
Trusts who submitted returns, sometimes with significant difficulty, and who
responded to our enquiries.
Members of the Evaluation Subgroup contributed to design of the evaluation,
critically reviewed the individual PCT summary returns, and commented on the
manuscript. Dr Julie George extracted the ImmForm data. We thank Dr Mary
Ramsay and Karen Wagner for the use of Table 8, Julian Hiscock for database
management, and Amanda Wright for proofreading the manuscript.
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