Pertussis – the continuing epidemic
Dr Rosemary Lester
Acting Director and Acting Chief Health Officer
Health Protection Branch
14 February 2012
Outline
Rosemary Lester
Overview of pertussis
The epidemiology of pertussis in Victoria
The Government’s response – parental vaccination program
Initial uptake – 2010 survey
Stacey Rowe
Parental Whooping Cough Vaccination Survey
• Methodology
• How to administer the survey
• Questions
Overview of pertussis
Respiratory illness caused by bacterium Bordetella pertussis
Highly infectious – spread by respiratory droplets
Incubation period – 6 to 20 days, usually <14 days
Infectious period – just prior to onset and, if untreated, for up to 21
days after cough onset
Infants <12 months are most at risk of complications and death
• Most hospitalised, many ICU admissions
• Morbidity – hypoxia and resultant brain damage, seizures
lung scarring, broken ribs etc.
• Mortality – approx 1 in every 200 cases <6mo will die
The continuing epidemic
Epidemics observed every 3-5 years
Remains endemic in developed countries:
• Australia, Canada, Japan, Italy, The Netherlands,
Sweden, USA
All report recent increases
Victoria’s current epidemic
• Notifications increased markedly since 2008
• 8,489 cases notified in 2011 alone; nearly 8-times greater
than the 2007 annual total
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Number of notified cases
Notified cases 2007 to 2011
Notified cases of pertussis by month and year of notification, 2007-2011, Victoria
1200
1000
800
600
400
200
0
2007
2008
2009
Year and month of notification
2010
2011
The continuing epidemic: infants aged < 12 months
Whilst the vast majority of cases are among adults, infants aged
less than12 months are most vulnerable
In five years (2007 – 2011), 634 cases of pertussis were
notified in children <12 months of age
Of these, 477 (75%) were aged <6 months
• no immunity until received 3 doses of pertussis –
containing vaccine at 2, 4, and 6 months of age
Notified cases 2007 to 2011 (<12 and <6 months)
40
Notified cases of pertussis in children aged less than 12 months, by month and year of notification, 2007
to 2011, Victoria
35
< 6 months
6-11 months
25
20
15
10
5
0
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
Number of notified cases
30
2007
2008
2009
Month and year of notification
2010
2011
Pertussis-containing vaccination coverage
DTPa coverage by quarter and childhood age cohort, Victoria,
March 2007 to December 2011
100
95.22
95
92.05
90
12-15 months
24-27 months
85
60-63 months
80
Date of calculation
Dec-11
Sep-11
Jun-11
Mar-11
Dec-10
Sep-10
Jun-10
Mar-10
Dec 09
Sep 09
Jun 09
Mar 09
Dec 08
Sep 08
Jun 08
Mar 08
Dec 07
Sep 07
Jun 07
75
Mar 07
Per cent coverage
93.53
The Government’s response
15 June 2009 - Parental whooping cough vaccination program
• Free pertussis-containing vaccine (Boostrix®)
• Parents of new babies eligible (incl. adoptive/foster)
• Time-limited program
Program rationale – to protect unimmunised babies from
infection with pertussis by vaccinating parents – referred to as
“cocooning strategy”
Delivery of vaccine is being encouraged through:
• Maternity hospitals
• General practice
• MCH nurses
• Local Government immunisation
2010 survey
Attitudes, awareness, uptake survey
• Smaller sample of parents whose babies were born in Q1 2010
• 10 LGAs – 5 rural, 5 metro
• Mail-out survey direct to parents
Results
• 166 families participated from 9 LGAs
• 69% mothers and 53% fathers had had the vaccine
• Reasons for not being vaccinated:
• Not being aware of the availability of the free vaccine
• Time and effort involved to be vaccinated
Limitations
• Poor response rate – 41%
• Logistical challenges – Sampling and distribution
Next steps
Nationally
• Vaccine effectiveness studies
• Various laboratory research going on – to examine molecular
characteristics of Bordetella Pertussis
• ? Additional booster in second year of life
• Repeat survey to measure uptake of vaccine (Vic) – Stacey…
Parental whooping cough vaccination survey
Stacey Rowe
Senior Epidemiologist
Communicable Diseases Prevention and Control Unit
14 February 2012
Survey Aim and Methodology
Aim
To obtain a coverage estimate on the parental whooping cough vaccination
Methodology
State-wide distribution
Four consecutive weeks – 15 February to 14 March, inclusive
Parents attending 4 month Key Ages and Stages consultation
MCH nurse administered
The survey
• Short: focuses on whether, where and when
• No personal identifying information being collected
• Not onerous for either MCH nurses/parents
Distribution of survey and related materials
Distribution
Sent from our warehouse to all MCH coordinators on Friday 3 February
Most of you will have received it already
What will you receive?
1. The survey (1 pager)
– 1 for each child expected to attend 4 month KAS consultation
2. Plain Language Statement (1 pager)
– 1 for each parent(s)
3. Information sheet (1 pager, double-sided)
– 1 for each MCH Office
4. Reply-paid envelopes
– At least 1 per 20 surveys
The survey
How to administer survey
How to administer survey
Who can participate?
• Birth, foster and adoptive parents
• One parent can respond for both – complete two columns
• Single parent – complete one column
Informed consent
Explain to parents:
• What the survey is about
• Why it’s being conducted
• What their participation will involve
Provide parents with Plain Language Statement
Request their consent – tick box on front of survey
Consent + initial questions
Vaccinated: Whether, where, when, + why not
Frequently asked questions
Some explanation about the questions
Question 4 – Have you had the whooping cough vaccine in
relation to the birth of your most recent child?
• Why “in relation to”?
It excludes those who may have already had the vaccine
for other reasons (captured elsewhere):
– Previous child, or newborn relative
– Vaccinated in year 10 at school
It helps narrow the subsequent question of “when”
Question 4b – What date did you have the vaccine?
• Ideally – obtain actual date (dd,mm,yyyy)
• Otherwise, use approximations (check boxes)
Frequently asked questions (cont.)
Question 4c – If you did not have the vaccine, why not?
• Already had the vaccine since 2004
– Boostrix only became available in 2004
– People who have had vaccine since 2004 don’t need it again
• Did not know the free vaccine was available
• Other (use back of survey if need more room)
–
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–
–
–
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–
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Not being aware of the risks of the disease
Don’t consider the disease serious enough to be vaccinated
Costs associated with going to the doctor
Time and effort involved with getting vaccinated
Potential side effects of the vaccine
Concerns regarding how well the vaccine works
Don’t like needles
My religious beliefs
Demographics
Other considerations
Parents need not feel that they are being criticised for not
having received the whooping cough vaccination
You may wish to use this conversation with parent(s)
opportunistically, and link unvaccinated parents in to
your immunisation providers to encourage vaccination
Survey returns
Return of surveys to Department of Health
• End of survey period – 15 March 2012
• Intermittently throughout survey period (large caseloads)
• Reply-paid envelopes (call 1300 651 160 if requiring more)
Questions?
• Stacey Rowe – 1300 651 160
• stacey.rowe@health.vic.gov.au
Distribution of results
Survey results reported to:
• MCH workforce
• LGA immunisation committees
• Chief Health Officer
• DEECD
• National communicable disease networks