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An experimental Brazilian dengue vaccine, which was tested on 16,235 volunteers over two years, showed an average efficacy of 79.6% in phase three clinical trialssaid the Butantan Institute of São Paulo, one of the most prestigious medical research institutes in the country.
It was detailed in a note that there were no serious cases of dengue in participants in the phase three study, which has been ongoing since 2016.
The single-dose formula it was administered to 10,259 of the volunteerswhile the rest received 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 denguealthough it decreased to 73.5% in those who have never had contact with the disease.
Dengue is a disease caused by the bite of female Aedes Aegypti and Aedes albopictus mosquitoes infected with the DENV virus.
The Butantan vaccine is designed to act against the four sorotypes of the dengue virus (DENV-1, DENV-2, DENV-3 and DENV-4)although in the study period the efficacy could only be verified with the first two types, since they were the ones circulating in Brazil at the time.
Dengue can occur multiple times in a person depending on the circulating serotype.
If a person is infected with one of the serotypes, lifelong immunity to that serotype is produced, and cross-immunity to other serotypes only for a short time; be able to become infected after the other serotypes.
The manifestation of dengue with warning signs or the severe form occurs when a person is first infected with one of the serotypes and then with a different serotype, which causes an increase in antibodies against the first serotype and the lack of production of antibodies for the second.
So, on the one hand there is an exaggerated immune reaction to a virus that is not in the body and on the other hand the amount of virus of the serotype that is not attacked increases, which favors the development of symptom severity.
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Phase three trials will continue until complete efficacy data is obtained with all four sorotypes.
Currently in Brazil, only one vaccine is approved by the health authorities, available only in the private network and applicable to patients who have already had dengue.
A continental level, nearly 500 million people in America are at risk of contracting the virusaccording to the Pan American Health Organization (PAHO).
Around 400 million people worldwide suffer from dengue every year.
In Ecuador, among the vector-borne diseases, Dengue is a priority public health problem due to the high number of cases that occur each year.
Since its resurgence in late 1988, several epidemic cycles have been recorded, with tropical and subtropical areas of the country at risk of transmission of this arbovirus. (I)
