Pakistan has come a long way in its struggle to eradicate poliomyelitis (polio). In the early 1990s, the annual incidence of polio was estimated at more than 20 000 cases a year.
Since its initiation in 1994, the national polio eradication programme has made major strides in reaching children with immunization in all parts of the country, resulting in a decrease in the number of cases to a low of 28 cases in 2005.
However, since then progress has been hampered by instability and war in border areas with Afghanistan, limiting safe access to children.
The programme has also faced managerial problems in certain areas, with the result that children in key high-risk areas do not receive adequate doses of oral poliovaccine.
As a result of these factors, the number of cases of polio increased annually to reach 198 in 2011.
The high-risk areas comprise four zones: Federally Administered Tribal Areas; Khyber Pakhtunkhwa province; the Quetta block in Baluchistan; and the Karachi towns of Gadap, Baladia and Gulshan E Iqbal.
More than three quarters of cases are reported from these high-risk districts. Most wild viruses reported from cases in other areas are genetically linked to those of these high-risk areas.
To address this situation, considerable effort has been made by the Pakistani polio eradication programme, with the support of WHO. This includes:
introduction of bivalent oral polio vaccine
development of comprehensive district-specific plans
improvements in the monitoring system through introduction of finger-marking and independent monitoring
intersectoral collaboration in polio eradication.
At the same time, emphasis is placed on maintaining a comprehensive surveillance system supported by a well-functioning polio laboratory.