A large outbreak of poliomyelitis following temporary cessation of vaccination in Samarkand, Uzbekistan, 1993-1994

Abstract

Oral poliovirus vaccine (OPV) was not available in Samarkand, Uzbekistan, from November 1992 to August 1993. The ensuing outbreak of poliomyelitis was investigated: Patients with poliomyelitis were evaluated, the extent of poliovirus circulation was estimated, and the effectiveness of control measures was assessed. Between March 1993 and April 1994, 74 cases of paralytic disease attributable to poliovirus type 3 were reported. Cases originated from 63% of districts; 88% of cases were children ≤2 years old, and the highest attack rates were for infants 9-11 months (65/100,000) and 12-14 months (60/100,000). Most patients were either unvaccinated (45%) or inadequately vaccinated (23%). Limited quantities of OPV became available in September 1993 and were provided to infants (3 doses) and 1-year-olds (2 doses), controlling rapidly the outbreak in these age groups, but cases continued, primarily among older children, until April 1994. These findings suggest that control efforts should be guided by the age distribution of the children with poliomyelitis.