Research in the New England Journal of Medicine in February 2024 shows that a vaccine candidate against dengue from Brazil’s Instituto Butantan was largely effective at preventing symptomatic infection. This paper comes as the country and wider region experiences a surge in cases, with health authorities in Rio de Janeiro declaring a health emergency ahead of Carnival.
Cases rise
PAHO data on the dengue epidemiological situation in the region between epidemiological weeks (EW) 1 and 3 of 2024 reveal a suspected 339,719 cases of dengue; this is a cumulative incidence of 41 per 100,000 population.
“This figure represents an increase of 157% compared to the same period in 2023 and 223% compared to the average of the last 5 years.”
PAHO reports that of these reported cases, 95,868 were laboratory confirmed and 391 were classified as “severe dengue”. The BBC quotes Rio de Janeiro’s health secretary, Daniel Soranz, who emphasised the importance of reducing serious cases and deaths.
“Early treatment makes all the difference.”
A vaccine is needed
Although two vaccines have been approved in Brazil, from Sanofi Pasteur and Takeda, Brazil-based researchers have been working on a vaccine. The single-dose vaccine from Instituto Butantan, Butantan-DV, contains attenuated versions of all four dengue virus serotypes.
The latest research presents the results of the first two years of a Phase III trial involving 16,235 participants. It indicates an overall efficacy of 79.6%:
- For participants between 2 and 6 efficacy was 80.1%
- For participants between 7 and 17 efficacy was 77.8%
- For participants between 18 and 59 efficacy was 90.0%
Although serotypes 3 and 4 were not in circulation during the follow-up period, the investigation revealed that efficacy was 89.5% against serotype 1 (DENV-1) and 69.9% against serotype 2 (DENV-2). Most adverse events were mild or moderate, with main responses being injection side pain or redness, headache, and fatigue. All severe adverse events recovered.
Dr Maurício Lacerda Noguiera, a trial coordinator, believes that efficacy against DENV-3 and DENV-4 will be “good”.
“It should be stressed that Butantan Institute’s vaccine has also proved extremely safe for people who have never had dengue, which is an advantage over the vaccines now available on the market. Furthermore, it can be administered to a broader age group and a single dose is sufficient.”
Looking ahead
Dr Esper Kallás, infectious disease specialist and first author, commented on the “rigour and quality” of the work behind the research, which took place in 16 centres across “all five regions of the country”. Dr Kallás stated that the plan is to submit a report to Brazil’s health surveillance agency, ANVISA, later this year, to apply for registration.
“If all goes well, we’ll win definitive approval for the vaccine in 2025. We already have the infrastructure to produce it at Butantan Institute, although it can still be perfected. After all, it’s tetravalent, corresponding to four vaccines in one.”
We’re looking forward to hearing more from Dr Fernanda Boulos of Instituto Butantan on the challenges and opportunities in vaccine development for dengue at the Congress in Washington in April. Don’t forget to get your tickets here or subscribe for weekly newsletters here.
