Control of a type 1 poliomyelitis epidemic in British Guiana, 1962-63, with trivalent oral poliovirus vaccine. 1. Epidemiological aspects

An epidemic of poliomyelitis took place in British Guiana during the winter of 1962-63. A total of 485 paralytic cases occurred over a 10 week period, 90 percent in children under 5 years of age. The attack rate for the total population of more than half-a-million persons was 86.5 per 100,000. Type 1 poliovirus was isolated from stool specimens from 90 percent of the paralytic cases studied. Early in the epidemic, before virus was isolated, plans were developed for an extensive field study to characterize the epidemic and evaluate the effectiveness of trivalent vaccine as a practical control measure. Vaccine was administered to 85 percent of the children aged 5 or less over a 4-week period. A definite beneficial effect was noted; however, the epidemic might have been more impressively terminated had the programme been more rapidly administered. The importance of early recognition of an outbreak of poliomyelitis and of the rapid planning and execution of a vaccination programme is stressed. (AU)

Control of a type 1 poliomyelitis epidemic in British Guiana, 1962-63, with trivalent oral poliovirus vaccine. II Virological aspects

Epidemics of paralytic poliomyelitis has 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 percent 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 (AU)

The control of a Type 1 poliomyelitis epidemic in British Guiana, 1962-1963, with trivalent oral poliovirus vaccine

A total of 485 paralytic cases occured over a ten week period, 90 percent under age 5. Vaccine was administered to 85 per cent of the children age 5 or less over a 4 week period. A definite beneficial effect was noted: the effectiveness rate was calculated to be 86 per cent (AU)