A new study has found that oral vaccines could prevent up to 60 percent of cholera cases in the first two years after vaccination.
The vaccines have been shown to provide protection within one month of vaccination, but data from studies of older versions of the vaccines suggest that protection is unlikely to last more than three years, said David Sinclair, of the Liverpool School of Tropical Medicine in the United Kingdom, and colleagues at the International Centre for Diarrheal Disease Research in Bangladesh.
"Booster doses in line with the manufacturers' recommendations will be required and the vaccines appear to be safe and not linked to any serious side effects," Sinclair said.
Cholera infection can lead to severe diarrhea that causes dehydration and death if not treated promptly.
For the review, authors looked at 40 studies that examined the effect of cholera vaccinations incorporated into a routine vaccination schedule in areas of the world where the disease is prevalent.
They calculated how effective vaccines were using data from the four largest studies, which included 249,935 participants
In these studies of vaccines made from killed, whole-cell cholera, the number of cholera cases among all participants dropped by 52 percent in the first year after vaccination, falling even further to 62 percent in the second year after vaccination.
Among children under five, however, the number of cases dropped by only 38 percent.
The study appeared in the latest issue of The Cochrane Library.