Misleading Negative Findings in a Field Trial of Killed, Oral Cholera Vaccine in Peru

Abstract

To the Editor —The recent paper by Taylor et al. [1] discusses whether a 2-dose primary regimen of recombinant B subunit–killed whole cell oral cholera vaccine protected against El Tor cholera in a field trial done in Pampas, Peru. This is an important public health issue, because a 2-dose regimen may be financially and logistically feasible for developing countries. The authors conclude that a 2-dose regimen was not effective, although boosting with a third dose conferred protection. Unfortunately, there are several reasons to question the conclusion about a lack of protection by a 2-dose primary series of the vaccine