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

• Published in: The Journal of infectious diseases Vol. 182; no. 1; pp. 6 - 11
• Main Authors: Hennessey, Karen A., Marx, Arthur, Hafiz, Rehan, Ashgar, Humayun, Hadler, Stephen C., Jafari, Hamid, Sutter, Roland W.
• Format: Journal Article
• Language: English
• Published: Chicago, IL The University of Chicago Press 01.07.2000; University of Chicago Press; Oxford University Press
• Subjects: Biological and medical sciences; Case-Control Studies; Child, Preschool; Children; Disease eradication; Epidemiology; Health Services Accessibility; Human viral diseases; Humans; Immunization; Immunization Programs; Infant; Infectious diseases; Major Articles; Medical sciences; Oral poliovirus vaccine; Pakistan - epidemiology; Parents; Patient Acceptance of Health Care; Patient Compliance; Poliomyelitis; Poliomyelitis - epidemiology; Poliomyelitis - prevention & control; Poliovirus; Poliovirus 1; Poliovirus Vaccine, Oral - administration & dosage; Poliovirus Vaccine, Oral - therapeutic use; Predisposing factors; Risk Factors; Tropical medicine; Vaccination; Viral diseases; Viral diseases of the nervous system; Asia; Pakistan; Human; Nervous system diseases; Acute anterior poliomyelitis; Case control study; Eradication; Epidemiology; Infection; Prevention; Viral disease; Central nervous system disease; Risk factor; Spinal cord disease; Child; Public health
• ISSN: 0022-1899; 1537-6613
• DOI: 10.1086/315675

Despite substantial efforts to eradicate poliomyelitis by administering oral poliovirus vaccine 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 undervaccination among 66 poliomyelitis cases and 130 age- and neighborhood-matched controls. Cases were undervaccinated through routine immunization (matched odds ratio [MOR], 0.3; 95% confidence 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 informed, considering vaccination unimportant, and long distances to vaccination sites. Failure to vaccinate through routine immunization was a major risk factor for poliomyelitis in Pakistan. Successful NIDs alone will not interrupt poliovirus circulation in Pakistan, and children remain at risk unless routine immunization is strengthened or additional supplementary immunization is provided.