Number of confirmed cases of poliomyelitis
Rationale for use
The 1988 World Health Assembly called for the global eradication of poliomyelitis. The number of poliomyelitis cases is used to monitor progress towards this goal and to inform eradication strategies.
Definition
A case of poliomyelitis due to wild-type poliovirus is defined as a suspected case* with isolation of wild poliovirus in stool specimens collected from this suspected case or from a close contact of this suspected case.
*A suspected case is defined as a child less than 15 years of age presenting with acute flaccid paralysis (AFP), or as a person of any age with paralytic illness if poliomyelitis is suspected.
Data sources
Active surveillance and reporting of AFP, national and regional laboratory reports.*
* Most countries conduct active surveillance for acute flaccid paralysis among children less than 15 years of age. There are two mains quality indicators for AFP surveillance systems: the non-poliomyelitis AFP rate and the completeness of stool specimen collection. AFP surveillance is considered sensitive enough for certification purposes if countries report at least one case of non-poliomyelitis AFP per 100 000 population less than 15 years of age per year (i.e. a non-poliomyelitis AFP rate of at least 1), and if adequate stool specimens are collected from at least 80% of all AFP cases. Stool specimens have to be examined in a WHO-accredited laboratory.
Disaggregation
Since case base data are being collected, data can be stratified, analysed and disaggregated.
References
-
Poliomyelitis.
Geneva, World Health Organization, 2008 -
Global Polio Eradication Initiative.
Geneva, World Health Organization, 2008
Database
- Information on Vaccines, Immunization and Biologicals
- WHO Vaccine Preventable Diseases Monitoring System
Comments
The number of countries with endemic wild poliovirus circulation has decreased from >125 in 1988 to only 4 in 2007: Afghanistan, India, Nigeria and Pakistan. Three of the six WHO regions have already been certified as poliomyelitis-free: the Region of the Americas (1991), the Western Pacific Region (2000) and the European Region (2002). Poliomyelitis-free countries continue to conduct AFP surveillance to be able to detect and respond to possible re-importation of wild poliovirus from endemic areas.