Efficacy of short course antibiotic prophylaxis in controlling cholera in contacts during epidemic

During an epidemic of cholera, vaccination has limited applicability in controlling its spread. It has been seen that one out of every five to 10 V. cholerae-infected people develops diarrhoea severe enough to require hospital treatment. Most health authorities are concerned with this severely ill group in whom the majority of deaths occur. During the cholera epidemic of 1975 in Dacca two doses of tetracycline were administered to all family contacts of index cases. The control group of cholera cases did not receive the drug. The families were re-visited after 10-12 days and history of any diarrhoea and hospitalization was obtained. It was found that the subsequent diarrhoea or cholera cases occurring among the cholera contacts within 10-12 days were not different between the treated (13.5%) and the untreated (14.4%) groups. The occurrence of severe cases requiring hospitalization was, however, significantly reduced in the treated group (8.0% to 4.5%). In view of the emergence of V. cholera strains resistant to tetracycline, antibiotic sensitivity testing of epidemic strains would be needed before use of tetracycline for protecting cholera contacts as an immediate control measure.