Effectiveness of oral cholera vaccine three to five years after mass vaccination in Hue

ABSTRACT

From 1998, mass immunization using the locally-produced, killed oral cholera vaccine was conducted in half of the communes of Hue city followed by mass immunization of the remaining communes in 2000. In 2003, a cholera outbreak occurred in the city. The objective of the study is to assess the effects of vaccine after 3-5 years. The control group had the same address, sex and age with cholera patients. From May – August 2003, a total of 115 confirmed cholera cases were detected in Hue city. In this study, 48 cases were positive culture-confirmed and 21 cases was clinically suspected cholera. 62% cases had been vaccinated compared with 75% of the controls. The results showed that, using cholera vaccine in 1998 or 2000 conferred 50% protection against cholera during the 2003 outbreak