Abstract

PIP: Cholera epidemics, often involving new etiologic agents, are a major public health problem in developing countries. Although two new types of oral cholera vaccines--inactivated whole Vibrio cholerae O1 and attenuated strains of V cholerae O1--have been demonstrated to be safe, immunogenic, and effective, there has been a lag in their systematic use in areas with endemic and epidemic cholera. An open field trial conducted by Trach et al of a locally manufactured killed oral cholera vaccine resulted in a 60% reduction in the incidence of cholera in vaccinated versus nonvaccinated households in Hue, Viet Nam. Levels of protection in children 1-5 years of age were similar to those achieved in adults. Although the requirement for two spaced doses of this vaccine is a drawback, the potential for local manufacture overcomes the obstacle of high costs associated with imported vaccines. Attenuated V cholerae O1 vaccine strain CVD 103-HgR represents the most advanced application of the live oral vaccine approach. Small clinical trials in Asia, Latin America, Europe, and North America have indicated that a single dose confers complete protection against severe or moderate cholera caused by El Tor or classical biotype V cholerae O1 within eight days of administration.