6Widespread Paralytic Poliomyelitis in Pakistan: A Case-Control Study to Determine Risk Factors and Implications for Poliomyelitis Eradication

Despite substantial efforts to eradicate poliomyelitis by administering oral poliovirus vac-cine through routine immunization and annual national immunization days (NIDs), Pakistan reported 22 % (1147) of the worldwide cases in 1997. Reasons for continued high poliomyelitis incidence include failure to vaccinate, vaccine failure, or inadequate immunization strategies. A case-control study was conducted to measure vaccination status and reasons for under-vaccination among 66 poliomyelitis cases and 130 age- and neighborhood-matched controls. Cases were undervaccinated through routine immunization (matched odds ratio [MOR], 0.3; 95 % con®dence interval [CI], 0.1±0.5); however, NID immunization was similar for cases and controls (MOR, 0.6; 95 % CI, 0.3±1.2). Reasons for undervaccination included not being in-formed, considering vaccination unimportant, and long distances to vaccination sites. Failure to vaccinate through routine immunization was a major risk factor for poliomyelitis in Pak-istan. Successful NIDs alone will not interrupt poliovirus circulation in Pakistan, and children remain at risk unless routine immunization is strengthened or additional supplementary im-munization is provided. Despite a strong commitment to poliomyelitis eradication