Vaccine Preventable Disease Surveillance: Overview

Thomas Cherian, WHO

Global Framework on Immunization Monitoring and Surveillance (GFIMS)

l  An extension of the GIVS, published on December 07 - http://www.who.int/immunization/en/

l  Outlines a vision for immunization monitoring and VPD surveillance

–  Developed by WHO in collaboration with its global partners –  Call for integration of surveillance and monitoring systems –  Strengthening capacity at country level –  Emphasizes data quality assurance

l  Target/Audience –  Organizations that provide funding & support to immunization &

surveillance activities –  Country level health planners & decision-makers

Type of surveillance needs to be aligned to surveillance objectives

Example Objective Surveillance characteristics

Polio, measles Document eradication/elimination -find all chains of transmission; certification

Country-wide, active, with lab confirmation of all cases

Syndromic surveillance, avian influenza

Routine monitoring; outbreak detection investigation

Country-wide passive, aggregate reporting, with selective investigation

Meningitis, Invasive bacterial diseases, rotavirus

Networks of sentinel sites providing representative data for the population

Sentinel site surveillance

Hepatitis B; disease incidence based on regular home visits

Obtain epidemiological information Epidemiologic studies (detailed, labour intensive) and sero-surveys

Yes (182 countries or 94%) No (13 countries or 6%)

Countries Implementing Case-based Measles Surveillance, 2010

Source: WHO/IVB database, November 2011

Global VPD Laboratory Network, N~ 700 Labs

Polio and measles/rubella (109) Measles/rubella only (531)

Measles/rubella and yellow fever (14) Polio, Measles/rubella and yellow fever (13)

Labs/Institutes testing for: Polio only (23)

+ 331 (Prefecture Labs)

The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. © WHO 2009. All rights reserved

No data reported

B2

B3

D4

D5

D8

D9

H1

Incidence:(per 100'000)

<0.1

≥0.1 - <1

≥1 - <5

≥5

Genotypes:West Africa inset West Europe & Middle East inset

6

1

Chart proportional tonumber of genotypes

d11

G3

Distribution of measles genotypes, 2010

The boundaries and names shown and the designations used on this map do not imply the expression of any opinion whatsoever on the part of the World Health Organization concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted lines on maps represent approximate border lines for which there may not yet be full agreement. ©WHO 2011. All rights reserved.

Distribution of Measles Genotypes 2010

Laboratory confirmed measles but no sequences reported N=45

Acknowledgements: LabNet, P Chenoweth, O Beauvais

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1980

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Number of cases Official coverage WHO/UNICEF estimates

Source: WHO/IVB database, 2011 193 WHO Member States. Data as of September 2011

Pertussis global annual reported cases and DTP3 coverage, 1980-2010

Sero surveys for documenting impact of Hep B vaccination

Comparison of HBsAg Rate between 1992 and 2006 By Age, in China

Surveillance for new vaccines •  Based on detection and investigation of selected disease

syndromes •  Meningitis (Hib, pneumococcus, meningococcus, others) •  Pneumonias (Hib, pneumococcus, virus, others) •  Community acquired sepsis (pneumococcus, non-typhi salmonella, typhoid,

others) •  Diarrhoea (rotavirus, ETEC, shigella)

•  Sentinel site surveillance •  Selected sites capturing suspect cases/syndromes •  Selection of sites may depend on disease, population representativeness,

laboratory capacity •  Case ascertainment is usually facility-based, with or without defined

catchment population

Surveillance Structure "Tiered approach"

•  Not financially and operationally feasible to expect all sites to conduct all various surveillance activities. Surveillance structure considering a "tiered approach":

•  Hospital sentinel sites – "core sites": –  meningitis and rotavirus surveillance. –  1 per country, in larger countries up to 3 sites.

•  Additional select sites – "enhanced sites": –  Sepsis, pneumonia and other invasive disease surveillance. –  1 sites for every 3 countries.

•  Population-based sites to generate incidence estimates: –  1 one site per region (6 Regions + 3 AFRO sub-regions).

•  Centers of excellence •  Specialized epidemiologic studies to complement surveillance

Supported by laboratory network

Types of sentinel site surveillance

l Population-based laboratory surveillance (defined denominator)

–  Gold standard –  Provides incidence rates –  Can estimate cases of

disease caused by pathogen

–  Useful for monitoring impact of vaccine

–  Monitor serotype replacement

l Facility-based surveillance (no denominator)

–  Documents pathogen as a cause of severe disease

–  Proportion of disease syndrome caused by pathogen

–  Age distribution –  Serotype prevalence –  Antimicrobial resistance –  Case fatality ratios (for

hospitalized cases)

Vaccine impact evaluation in Malawi Trends in bacterial meningitis incidence, 1997-2005

•  Data provided by PBM Network, WHO-Malawi and Queen Elizabeth Hospital, Blantyre, Malawi.

•  AMP analysis

Introduction of Hib vaccine: February 2002

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1997 1998 1999 2000 2001 2002 2003 2004 2005

Incidence (per 100,000 per year)

Hib Blantyre City

Hib Blantyre rural

Sp Blantyre City

Sp Blantyre rural

Impact of Hib vaccine: based only on case counts

Lewis et al. Bull WHO 2008; 86:292-301

Using non-denominator based surveillance data: case control studies

Lewis et al. Bull WHO 2008; 86:292-301

Types of sentinel surveillance Bridging to get more comprehensive data

Facility-based Meningitis

Facility-based; All invasive bacterial diseases

Population-based

Vaccine clinical trials (probe)

Surveillance Research

Summary l  Polio and measles surveillance have provided a platform for

surveillance for VPDs –  Can be used to add on other diseases requiring country-wide surveillance –  Detection of epidemics

l  While aggregate reporting has been continuing for many years, quality of reporting needs improvement

–  Sub national data to monitor programme performance –  Pick up atypical cases, e.g. pertussis in young infants and older individuals

l  Sentinel site surveillance for invasive bacterial diseases and rotavirus diarrhoea being established, but need more work

–  Detailed presentation to follow

Thank you

Sentinel site surveillance l  Has been incremental progress with establishing a sustained

surveillance system, through MOH, for diseases targeted by new vaccines

–  Quality & yield needs improvement for IBD

l  Country ownership –  Personnel and infrastructure –  External funding to maintain quality, standards and coordination

l  Sentinel site surveillance systems have their limitations, even with improvement in quality

–  Need to complemented with special more intensive surveillance projects

l  Caution with over-interpretation of data from sentinel surveillance –  Need a minimal number of isolates and years of observation

Questions to SAGE

l Support the idea of sentinel site surveillance as proposed?

–  Alternative is to revert to only conducting time-limited project type surveillance

l Agree with the proposed steps to improve surveillance quality for IBD?

l WHO role in supporting surveillance? –  Will require resources to perform this role

21 Countries* eliminated MNT between 2000 & 2011 *(Plus 15 States out of 33 in India, Ethiopia part and 29 provinces out of 33 in

Indonesia) leaving 38 countries yet to eliminate MNT

MNT not eliminated

MNT eliminated prior to 2000 MNT eliminated since 2000

Source: WHO/UNICEF data base as of October 2011.

Over 100 million women reached with at least 2 TT doses from 1999 - 2010