Control of a type 1 poliomyelitis epidemic in British Guiana, 1962-63, with trivalent oral poliovirus vaccine. 2. Virological aspects.
Epidemics of paralytic poliomyelitis have been reported with increasing frequency in the Caribbean area over the last decade. During the first weeks of a type 1 poliomyelitis epidemic in British Guiana in the winter of 1962-63, it was possible to study "wild" poliovirus infections in pre-school children, and to obtain information concerning the effectiveness of a country-wide control programme using trivalent oral poliovirus vaccine.Serological studies indicated that many Guianese children had had previous asymptomatic poliovirus infections by school age. However, there were more children with antibodies to types 2 and 3 than with antibodies to type 1. Following the first of two feedings of trivalent vaccine, there were significant increases in the percentage of children with poliovirus antibodies.Though begun only three weeks after the hospitalization of several paralysed children, a rectal-swab survey indicated that in some areas over one-third of the pre-school children were excreting "wild" poliovirus. In one area of the country, where only 2% of the children were excreting poliovirus type 1, vaccine feeding seemed most effective in containing the epidemic. These results support the suggestion that to be successful an epidemic control programme in a developing tropical country should be rapidly organized and completed.