Herd protection and herd amplification in cholera.

Correspondence and reprint requests should be addressed to: Prof. David A. Sack Executive Director ICDDR,B: Centre for Health and Population Research GPO Box 128, Dhaka 1000 Bangladesh Email: [email protected] Fax: +(880-2) 882 3116 Recent analysis of results of the 1985 vaccine trial in Bangladesh showed that a killed oral cholera vaccine could provide herd protection (1), and this finding sheds new light on the potential utility of this vaccine and other oral cholera vaccines. Although there may be several mechanisms for herd protection, this finding of herd protection was somewhat unexpected.