EFFECT OF TARGET AGE OF SUPPLEMENTAL IMMUNIZATION CAMPAIGNS ON POLIOMYELITIS OCCURRENCE IN CHINA

The World Health Organization recommends conducting supplemental immun ization activities to eradicate poliomyelitis by the year 2000. Althou gh effective in eliminating poliomyelitis from the Americas, supplemen tal campaigns require substantial resources. To assess differential ca mpaign effectiveness in eliminating this disease, poliomyelitis occurr ence was compared in counties in China that targeted children <3 versu s <4 years of age. Counties that targeted children <3 years of age rep orted poliomyelitis more frequently after the campaigns. This associat ion was observed even after accounting for the effects of previous pol iomyelitis occurrence, urban versus rural setting, and population dens ity. While several limitations emphasize the preliminary nature of the se findings, these data support targeting the widest possible age grou p of susceptible children to ensure maximum effectiveness in eliminati ng poliomyelitis. Thus, while reducing the target age of these activit ies may result in considerable resource savings, such campaigns may no t be as effective in eliminating poliomyelitis.