Using Information to Close the
Primary/Secondary Care LoopFlu Vaccination Programme
Arlene Reynolds & Jim McMenamin
Health Protection Scotland
SCIMP, Crieff,
November 2013
Contents
• Influenza as a case study; How can we use
routinely gathered data to close the loop and
inform patient management?
– Aggregate level data
• Flu vaccine uptake & flu consultation Rates
– Individual level data
• Determinants of flu vaccine uptake &
vaccine effectiveness & risk of death
– Now that kids are to be vaccinated how do we
propose to describe the Public Health benefit?
Why vaccinate
against Flu?
• In absence of a flu vaccination programme
NHS Scotland would experience significant
morbidity and mortality each season*
– 900 excess deaths
– 4700 excess hospitalisations
– 100,000 excess GP consultations
*Extrapolation from - Baguelin M, Flasche S, Camacho A, Demiris N, et al.
(2013) Assessing Optimal Target Populations for Influenza Vaccination
Programmes: An Evidence Synthesis and Modelling Study. PLoS Med 10(10):
e1001527. doi:10.1371/journal.pmed.1001527
http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001527
Flu Vaccine Uptake –
a success story…
• Scotland is one of only three EU countries to
consistently achieve a vaccine uptake of
greater than 75% in those age 65 and over
• Uptake in under 65’s in CMO defined risk
groups around 60%
• GP consultation rates for Influenza Like Illness
(ILI) vary markedly each season but rates of
illness much less in last decade c.f. prevaccination programme
What does Primary
Care data tell us?
• Uptake by risk group?
• When season starts & magnitude compared
with previous years?
• Who is affected most & Where?
• What Flu strains are responsible?
• If not Flu what is it (and do I need to treat it)?
• Is Flu Vaccine protecting the population?
Cumulative vaccine uptake
by risk group over time
season 2012/13
How quickly is offer of vaccine taken up?
100%
Over 65
Vaccine uptake (%)
80%
All risk groups (under 65)
Chronic Respiratory Disease
Chronic Heart Disease
60%
Chronic Renal Disease
Chronic Liver Disease
40%
Chronic Neurological Disease
Diabetes
Immuno-compromised
20%
Pregnant/no risk**
Pregnant/at risk**
Carers
0%
Week Week Week Week Week Week Week Week Week Week Week Week Week
12
10
8
6
4
2
52
50
48
46
44
42
40
Week number
** The size of the pregnant population is derived from GP records on patients with pregnancy code. This results in
changes in the population over the course of the season, as pregnancy status of patients changes.
When Season Starts &
Magnitude?
• Since 2009 daily automated extraction of
aggregate data from 99% of all practices on
GP consultation rates for Influenza Like Illness
(ILI) & Acute Respiratory Infections
– Rates vary markedly each season
– Timing of peaks in clinical presentations
variable
• In the main around the time of the Festive
season
• But earlier in 2003/4
• And later in 2010/11
Weekly GP consultation rates for ILI
by flu season Scotland
(In 2012/13 = 961 practices)
Weekly GP consultation rates for ILI by flu season Scotland
(In 2012/13 = 961 practices)
2007/08
ILI rate per 100,000 pop
350
Christmas
300
2008/09
250
2010/11
200
2011/12
150
100
2012/13
50
2009/10
0
40
42
44
46
48
50
52
2
4
6
8
10
12
14
16
18
20
8
week
Who is affected most?
GP consultation rates for ILI in Scotland by age group;
weekly rates per 100,000 population, week 40 2012 to week 32 2013
<1
1-4
5-14
15-44
45-64
65-74
>=75
80
60
50
40
30
20
10
Week
38
36
34
32
30
28
26
24
22
20
18
16
14
12
10
8
6
4
2
52
50
48
46
44
42
0
40
ILI rate per 100,000 population
70
9
Where?
NHS board ILI consultation rates to
16th October 2013
10
What Flu strains are
responsible?
Weekly summary of GP sentinel swab positivity (number positive and percentage positive) by
influenza subtype, week 40 2012 to week 20 2013 (at week 22 2013)
60
100
90
80
70
40
60
30
50
40
20
% of samples
Number of positives
50
30
20
10
10
0
0
week
A(H1N1)pdm09
A(H3)
Type A (subtype unknown)
Type B
A(H1N1)pdm09 %
A(H3)%
Type A %
11B %
Type
If its not Flu what is it?
(Do I need to treat it…?)
100
100
90
90
80
80
70
70
60
60
50
50
40
40
30
30
20
20
10
10
0
% positive
Number of positives
Number of laboratory confirmed seasonal respiratory pathogens submitted through Sentinel
sources, week 40 2012 to week 20 2013 (at week 22 2013)
0
40 41 42 43 44 45 46 47 48 49 50 51 52 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
week
Influenza virus
Coronavirus
Human metapneumovirus
Respiratory syncytial virus
Para-influenza
Mycoplasma pneumoniae
Rhinovirus
Adenovirus
% positive Influenza
12
The PIPeR cohort –
Determinants of
Flu vaccine uptake &
Vaccine effectiveness
• Daily Consultation rates for
– ILI
– ARI (including asthma)
– ILIARI (ILI+ARI excluding asthma)
• Weekly download of individual level data from each
practice
• 170783 Patients for 2012/13 cohort
– Patients registered with 27 GP Practices (25
physical sites) on Sept 1, 2012
– 3.3% Scottish Population
Colours represent the
different postcode areas of
practice population
14
20
40
0-4
5-14
15-44
45-64
65-74
75+
0
Percentage
60
80
Vaccine Uptake
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
15
Vaccine Uptake
10
5
0
Percentage
15
20
Female
Male
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
16
Vaccine Uptake
0
1
2+
20
15
10
5
0
Percentage
25
30
Consultations in Previous Season
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
17
Vaccine Uptake
5
10
15
Urban
Small Towns
Rural
0
Percentage
20
Urban Rural Status
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
18
Vaccine Uptake
[1,4]
(4,8]
(8,12]
(12,16]
(16,20]
10
5
0
Percentage
15
20
Deprivation
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
19
Vaccine Uptake
0-4
5-14
15-44
45-64
30
20
10
0
Percentage
40
50
In a Risk Group
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Date in 2012/13
20
Vaccine
effectiveness
for entire season
21
Methods
• Method 1: Test Negative Case Control
– GP Sentinel Swabbing Scheme
– Interim & End of Season estimate
– Adjustment for UK site, time period, sex, flu strain
• Method 2: Cohort method
– Weekly download of individual level data from
each practice
– Adjustment for a range of confounders
– Nested case control (Gold Standard)
– (Adhoc investigation of potential adverse reaction)
– Linkage to hospital data and deaths
“Overall trivalent influenza vaccine (TIV) adjusted vaccine effectiveness
(VE) against all laboratory-confirmed influenza in primary care was 51%
(95% confidence interval (CI): 27% to 68%); TIV adjusted VE against
influenza A alone or influenza B alone was 49% (95% CI: -2% to 75%)
and 52% (95% CI: 23% to 70%) respectively. Vaccination remains the
23
best protection against influenza. “
Cohort: Calculation of
vaccine effectiveness
• Seasonal Flu Vaccine
– Time dependent covariate
– 14 days for consultation post vaccine to count
• Time dependent Cox regression
• Comparing
– Unvaccinated at time of consultation
– Vaccinated at time of consultation.
24
VE – Clinical
endpoint
VE
-
All ages
Age 65+
At risk
under 65
21.8% (95% CI 1.9 to 37.6)
-35.4% (95% CI -173.9 to 33.1)
28.6% (95% CI 4.0 to 47.0)
Period is December 01, 2012 to February 28, 2013
Adjusting for age, gender, clinical risk group, deprivation, urban/rural, seasonal
vaccination in previous year, number of ILIARI consultations in the previous
year.
25
Linking primary &
secondary care data
• What is the increased risk of death from
influenza in clinical risk groups?
– Data linkage - primary care, laboratory,
SMR1 & NRO(S) - the SIVE project
Severe Acute Respiratory Infections
(SARI) due to laboratory confirmed
influenza
26
40
42
44
46
48
50
52
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
number of influenza ICU cases
60
Influenza cases requiring ICU
50
250.0
40
200.0
30
150.0
20
100.0
10
50.0
0
0.0
2010/11
2011/12
season and week
2012/13
27
ILI Rate per 100,000 pop
What does risk factor analysis of
SARI cases tell us?
300.0
GP consultations for ILI
28
Vaccine effect varies for different
clinical endpoints – deaths by
season 2000 to 2008/9
“Marked variation of vaccine
effectiveness in any one year –
need to look at the average
effect over time…” NIHR
Interested in routine flu output?
30
31
Season 2013/14
• Childhood extension of seasonal influenza vaccination
programme with LAIV – Fluenz
– Phase 1 (of 3)
• All Scottish 2 & 3 year olds ~ 120k
• Pilots in primary school (age 4 to 11 years) ~ 100k
• TNCC - Increased swabbing resource (from 2k to 3k
samples) to allow better VE by age strata
• Cohort
– Increase cohort size from 27 to 47 practices ~ 300 –
350k patients
– Expand clinical data to include rotavirus & Zoster?
32
Making sense of it all:
Modelling,
Programme Effectiveness &
Benefit Realisation
33
Benefit Realisation- Influenza: Then, Now and Next?
IMPACT
Measure
Annual Deaths
Then –
Now Next No
Current Programme
Programme Programme Extension
900
500
300
Burden*
Consultation rates
Levels of
infection/ risk Vaccine uptake (&
Effectiveness)
of
transmission
Transmission
Health Care
Utilisation*
Societal
Burden
Annual
Hospitalisations
Annual GP
Consultation
Health Economic
costs
High
Low
4700
2700
1600
100000
75000
42000
LSHTM
LSHTM
LSHTM
High
200
less
Indirect &
direct
Indirect &
75% (30-70) 75% (50-80)?
direct
“supershed
ders”
Mod
Low
reduced
Mod
NA
Health
Gain?
Next v
Now?
1100
less
33000
less
PENSIVe
pilot
* LSTM&H assumptions – 1. Uptake limited to 30% in 2-16 years; 2. Modelling includes indirect benefit through “herd-immunity”
protection of adult groups; 3. Census data 2010/11 England & Scotland population estimates as 53 million & 5.3 million respectively
The future…
• Applicability of public health surveillance
programme approach to other vaccine
preventable diseases?
– E.g. rotavirus, shingles etc
– Demonstration of their public health
effectiveness
• Single data extraction of primary care data
and linkage with other NHS datasets SPIRE
35
36
Acknowledgements
•
•
Sentinel Swabbing Scheme practices 2012/13
– Bridgeton Health Centre, Aberfeldy & Kinloch Rannoch Medical Practice, Airthrey Park
Medical Centre, Kilwinning Medical Practice, Glenfield Medical Practice, Ardach Health
Centre, The Cairntoul Practice, Braids Medical Practice, Carnoustie Medical Group,
Carstairs Surgery, Bourtreehill Medical Practice, The Craigshill Partnership, Cramond
Medical Practice, Barns Medical Practice, Dr Langridge, Alva Medical Practice,
Riverview Medical Centre, Greencroft Medical Centre (North), Neilston Medical Centre,
The Surgery, Keith Health Centre, Kelso Medical Group, Dr Jabaroo & Partners,
Liberton Medical Group, Meadowbank Health Centre (Practice 3), Newton Port
Surgery, Primrose Lane Medical Practice, Ranfurly Surgery, Dornoch Medical Practice,
Skerryvore Practice, Tweeddale Medical Practice, Dr Blake & Partners, Dunbar
Medical Centre, Red Surgery, Riverview Practice,West End Medical Practice,
Westgate Medical Practice, Yell Health Centre,Denny Cross Medical Centre
PIPeR practices 2012/13
– Bridgeton Health Centre, Kilwinning Medical Practice, Glenfield Medical Practice,
Waverley Medical Practice, Eden Villa Practice, The Cairntoul Practice, Dr Langridge,
Alva Medical Practice, The Health Centre, Riverview Medical Centre, Greencroft
Medical Centre (North), Neilston Medical Centre, Dr Jabaroo & Partners, Lochinch
Practice, Lochnaw Practice, Loch Ree Practice, Meadowbank Health Centre (Practice
3), Primrose Lane Medical Practice, Dr Cassidy & Partners, Bonnybank Medical
Practice, Stevenston Medical Practice , Auchinleck Health Centre, Hospital Hill
Surgery, Inverkeithing Medical Group, Denny Cross Medical Centre, Brown Spilg 37
Partnership, Drs Owen, Smith & Johnstone