New-generation, orally administered cholera vaccines offer the promise of improved control of cholera in sub-Saharan Africa.
However, the high prevalence of human immunodeficiency virus (HIV) infection in many cholera-affected African populations has raised doubts about the level of protection possible with vaccination.
Dr Deen and colleagues evaluated a mass immunization program with recombinant cholera-toxin B subunit, killed whole-cell oral cholera vaccine in Beira, Mozambique, a city where the seroprevalence of human immunodeficiency virus is 20% to 30%.
The researchers undertook mass immunization of nonpregnant persons at least two years of age, using a two-dose regimen of the cholera vaccine in Esturro, Beira (population 21,818) from December 2003 to January 2004.
The investigators then assessed vaccine protection in a case–control study during an outbreak of El Tor Ogawa cholera in Beira between January and May 2004.
|The cholera vaccine was equally effective in children younger than 5 years of age and in older persons|
|New England Journal of Medicine|
The investigative team found that receipt of one or more doses of the cholera vaccine was associated with 78% protection.
The researchers considered antecedent rates of vaccination between persons with culture-confirmed cholera severe enough to have prompted them to seek treatment.
The team then compared this group with and age- and sex-matched neighborhood controls without treated diarrhea in order to estimate the level of vaccine protection.
The research team then assessed the effectiveness of the cholera vaccine in 43 persons with cholera and 172 controls.
In addition, the researchers also found that the vaccine was equally effective in children younger than 5 years of age and in older persons.
The investigative team concurrently conducted a case–control study designed to detect bias compared persons with treated, noncholeraic diarrhea and controls without diarrhea in the same population.
The team found no protection associated with receipt of the vaccine.
Dr Deen concluded, “The recombinant cholera-toxin B subunit, killed whole-cell oral cholera vaccine was highly effective against clinically significant cholera in an urban sub-Saharan African population with a high prevalence of human immunodeficiency virus infection.”