Causality assessment of adverse event following immunization, 2014 pdf, 938kb

69 Pages·2014·0.9 MB·English

SEA-Immun-88
Distribution: General
Causality assessment of adverse
events following immunization
Report of an intercountry workshop
18–20 February 2014, Bangkok, Thailand
© World Health Organization 2014
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Contents
Page
Acronyms .............................................................................................................. v
Executive summary ............................................................................................... vi
1. Background ................................................................................................... 1
2. Methodology and objectives .......................................................................... 4
3. Proceedings ................................................................................................... 7
Annexes
1. List of participants ....................................................................................... 15
2. Agenda ........................................................................................................ 18
3. Summary country profile, status of AEFI and performances of vaccine
pharmacovigilance systems .......................................................................... 19
4. Case Study AEFI investigation report ............................................................ 24
5. Eight AEFI case reports with findings of working group and summary of
plenary discussions ...................................................................................... 26
6. Questionnaire to assess usefulness of causality algorithm tools to
participants ................................................................................................. 52
7. Plenary discussions ...................................................................................... 58
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Acronyms
AEFI - Adverse Events Following Immunization
NIP - National Immunization Programmes
NRA - National Regulatory Authorities
EPI - Expanded Programme on Immunization
LIC - Low-Income Countries
VPD - Vaccine Preventable Diseases
NCL – National Control Laboratory
CIOMS - International Organizations of Medical
HMIS - Health Management Information System
SIDS - Sudden Infant Death Syndrome
LMIC - Low and Middle-Income Countries
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Executive summary
The World Health Organization (WHO) Regional Office for South-East Asia
organized an intercountry workshop on causality of adverse events
following immunization (AEFI) from 18 to 20 February 2014 in Bangkok,
Thailand, as part of the regional strategy to support countries to strengthen
national vaccine safety surveillance and AEFI monitoring systems. Since
2008, WHO has provided training support to national regulatory authorities
(NRAs) and national immunization programmes (NIPs) in the South-East
Asia Region to strengthen capacity to detect, report and investigate AEFI.
WHO training material is utilized in all countries to conduct training
programmes. These programmes are adapted to local needs by national
immunization programmes and national regulatory authorities and National
AEFI committees for peripheral level immunization service delivery and
may be translated into local languages in some countries. WHO provided
follow-up support to some countries to establish national AEFI committees
and their secretariats, update national guidelines, implement pilot projects
to test and validate notification forms and investigation templates, and to
standardize data analysis and reporting. The countries of the South-East
Asia Region have thus experienced enhanced reporting of AEFI cases for
which the causes were not always understood. This resulted in unnecessary
concerns and disrupted routine immunization programme for some
vaccines in some countries.
As part of the strategy to address this risk of loss of public confidence
in the immunization programmes, the countries in the South-East Asia
Region strengthened their national AEFI committees with new members
with expertise in neurology, forensic specialists, paediatricians,
epidemiologists and professors in teaching hospitals. WHO proposed to
organize this intercountry workshop involving 29 vaccine experts from ten
countries in the South-East Asia and Western Pacific Regions to review,
discuss and analyse selected cases of AEFI for the period 2011–2013. WHO
country offices were instrumental in mobilizing national AEFI committee
members to identify specific AEFI case reports for discussion. Six out the ten
participating countries provided a total of 23 AEFI case reports. Not all
cases submitted could be reviewed because of time constraints and so nine
cases were short-listed and anonymized for the purpose of this workshop.
In addition to South-East Asia Region countries, Viet Nam in the WHO
Western Pacific Region participated in the workshop.
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The workshop provided a platform for experts in each country to
share their experiences and report on their performances in an open forum
with presentations using standardized templates. The new definitions for
AEFI and vaccine pharmacovigilance were presented and discussed in
plenary sessions. The WHO revised causality assessment methodology was
further tested in the process of reviewing selected cases and participants’
opinions on the usefulness of the tool were collected through a
questionnaire developed during the workshop. Participants appreciated the
opportunities to discuss with experts from different fields and learned a
great deal by working on AEFI case reports in the Region. All countries
acknowledge the need for further collaborative initiatives like this workshop
in the field of vaccine pharmacovigilance and developed a set of
recommendations to foster increased cooperation among countries in the
Region and beyond.
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1. Background
The Expanded Programme on Immunization (EPI) was established in 1974
at a time when only 5% of the world’s children were protected by
vaccination against six diseases, that is, polio, diphtheria, tuberculosis,
pertussis, measles and tetanus. Today, that figure is 83%, with some low-
income countries (LICs) reaching 99% immunization coverage.
Consequently, some vaccine preventable diseases (VPDs) are today on the
verge of eradication. The challenge for immunization programmes
throughout the world has become to maintain high immunization coverage
with VPDs disappearing from the collective memory. Vaccines are the safest
medicines with very rare serious adverse events following immunization
(AEFI). Although, serious AEFI are in the range of 1 per million doses, public
tolerance is much lower than for medicines because vaccines are given
mostly to infants who are healthy at the time the vaccine is administered. In
addition, vaccines are provided to children less than one year of age, a
vulnerable age in many LICs. A country with an infant mortality of 50 per
1000 live births may expect 14 deaths of children below one year every
day. As vaccination is routinely provided, those deaths could be attributed
to the vaccine when in fact they are coincidental and are due to
underlining diseases which were not diagnosed at the time of the
vaccination. Thus, it is essential to sustain public confidence in
immunization to establish surveillance systems that detect and report AEFI
in the national immunization programme (NIP), experts committees able to
conduct scientific AEFI causality assessments and ministry of health capacity
to address vaccine safety concerns.
The World Health Organization (WHO) has a long history of technical
support to build the national capacity of Member States in the South-East
Asia Region to monitor AEFI. In 2003, the WHO Regional Office for South-
East Asia established the Global Training Network (GTN) centre in
Colombo, Sri Lanka to provide training on AEFI monitoring to South-East
Asia Region Member States and to other WHO regions. The GTN centre in
Sri Lanka was instrumental in providing training on AEFI monitoring to
national regulatory authority (NRA) and EPI representatives of the countries
of the South-East Asia Region.
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Report of an intercountry workshop
Meanwhile, NRAs have initiated capacity-strengthening activities to
meet international/WHO standards for vaccine safety, quality and efficacy.
In the South-East Asia Region countries, national expertise increased and
new requirements emerged to further expand the basic AEFI course in
order to meet training requirements with new more complex vaccines and
additional experts added to the national AEFI committees. The WHO
course content of the basic AEFI training package was revised to cater to the
needs of national AEFI committees as they were being established by
NRAs/national control laboratories (NCLs) and NIPs with pharmacists,
experts in allergies, forensic specialists, professors in immunology, etc. who
were not always knowledgeable about their national vaccine safety
surveillance system.
To further support AEFI causality assessment, the revised AEFI training
material was tested in 2012 in Myanmar and Nepal with participants from
national AEFI committee members, NRA representatives and EPI managers.
In Myanmar1, the training methodology was adapted to maximize time for
participants to breakup in small groups to conduct formal causality
assessment of selected AEFI cases. Analyses of cases were reviewed in small
working group sessions using the WHO 2012 revised causality assessment
methodology for causality association and the findings were debated in
plenary sessions to reach consensus on the conclusions of the committee
about the causal association of the vaccine with the symptoms.
Since 2008, the Regional Office for South-East Asia has conducted 11
training workshops on AEFI monitoring in eight countries of the South-East
Asia Region, that is, Bangladesh, Bhutan, Democratic People’s Republic of
Korea, India, Indonesia, Nepal, Myanmar and Sri Lanka. The Regional
Office for South-East Asia support toward training on AEFI2 is a two-
pronged approach to address needs in the NRA capacity strengthening
programme
(1) for vaccine pharmacovigilance and the building of national AEFI
committee with national AEFI experts to periodically review cases
________________________
1 Report on the Training Workshop on Adverse Events Following Immunizaton 26–30 April 2012, Nay Pyi Taw,
Myanmar. Report available within Regional Office for South-East Asia/FHR/IVD library.
2 Adverse Events Following immunization in the South East Region 2008–2010; Report on WHO support to
training programme.
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