A dengue vaccine developed in Brazil has shown an average efficacy of 79.6% in phase three clinical trials, official sources said amid an explosion of cases of the disease in the country.
The results were obtained from the follow-up of 16,235 volunteers from all over Brazil over two years, reported the Butantan Institute in São Paulo, one of the country’s most prestigious medical research institutes.
No serious cases of dengue were recorded in participants in the phase three study, which has been ongoing since 2016. The single-dose formula was given to 10,259 volunteers, with the rest receiving a placebo. The researchers also looked at the effectiveness of the serum in cases of previous exposure to the virus.
In this sense, protection rose to 89.2% in people who had previously contracted dengue, although it decreased to 73.5% in those who had never had contact with the disease.
The Butantan vaccine is designed to act against the four serotypes of the dengue virus, although efficacy was only tested with two of them during the study period, as they were the ones circulating in Brazil at the time.
Phase three studies will continue until complete efficacy data is obtained with all four serotypes. Currently, only one vaccine is approved by health authorities in Brazil.
