IVI and Switzerland
Cholera Vaccine Effectiveness Trial
From 2009 to 2010, IVI conducted an oral cholera vaccine (OCV) effectiveness study in Tanzania in collaboration with the WHO, the Zanzibar Ministry of Health, and the Swiss Tropical and Public Health Institute with support from Sweden’s SIDA.
In January and February 2009, approximately 30,000 people aged 2 and over received two doses of the Dukoral OCV at study sites on Zanzibar and Pemba islands.
The result of the effectiveness trial showed the vaccine provided 70% protection during the first year of follow-up. IVI conducted an analysis of herd immunity conferred by the vaccine and found clear evidence of protection in those who were not vaccinated against cholera. This additional and indirect benefit of oral cholera vaccines helped further develop the case for the use of OCV, especially in outbreak situations.