Technician performs a visual inspection of the batch of Butantan DVRenato Rodrigues / Butantan Institute Communication
A single dose of just 0.5 milliliters (mL) of the candidate vaccine against dengue from the Butantan Institute, Butantan DV, provided lasting and elevated protection against the disease. It reduced the risk of people presenting symptoms (mild, moderate, or severe) of dengue by an average of 67.3%, even long after its administration—on average, 3.7 years.
Presented in an article published in August in the journal The Lancet Infectious Diseases, this level of protection is slightly lower than that observed in a study published in February in The New England Journal of Medicine (see Pesquisa FAPESP issue n° 324). In that study, the overall protection of the Butantan DV vaccine was 79.6%, but measured two years after administration. Now, with almost double the time, immunity has fallen a little but remains significant.
The new and most important data revealed now is that the vaccine provides elevated protection against the most worrying cases. It reduced the risk of those vaccinated developing severe dengue or dengue with warning signs by 89%, once exposed to the virus. Produced with an attenuated version of four varieties (serotypes) of the dengue virus, the Butantan-DV offered an average protection of 64.6% to those from 2 to 6 years of age, 70.6% for those 7 to 17 years of age, and 72.8% for those 18 to 59 years of age. It had an overall efficacy of 75.8% against dengue serotype 1 and 59.7% against serotype 2. Infections by serotypes 3 and 4 were not detected during the monitoring phase, concluded before the epidemic this year, and, for now, the level of protection provided by the vaccine against these two varieties of the virus is unknown.
“The peak of protection occurs during the first year of vaccination, after which a drop in the production of antibodies is normal. We will continue to monitor the data, but as of now, they suggest that it is not necessary to adopt a booster dose,” explains Fernanda Boulos, medical director of the Butantan Institute and coordinator of the clinical trials with Butantan DV, the initial development of which had funding from FAPESP.
In the tests, 10,259 people were selected to receive the vaccine, while 5,947 were administered an inactive compound (placebo). Neither the physicians nor the participants knew who was receiving what. The frequency of adverse events was greater among those who took Butantan-DV (53%) than among those who received the placebo injection (45.6%), generally local pain, fever, and red spots on the body. Meanwhile, the rate of severe adverse events was similar in the two groups: 6.2% in the first and 6.6% in the second.
“The vaccine remained highly effective and had solid safety data,” affirms physician and virologist Maurício Nogueira, of the School of Medicine of Rio Preto (FAMERP), lead author of the article in The Lancet Infectious Diseases and coordinator of one of the test centers. “We cannot afford to have a vaccine that is more or less safe,” he says.
According to Boulos, the new data are being submitted to the Brazilian Health Regulatory Agency (ANVISA), responsible for approving drugs and foods in the country, and the patent application for the vaccine has already been filed. The process of scaling up production and evaluating the quality of the vaccine is now underway. “Once this phase is complete, we will be able to calculate our production capacity better,” affirms the researcher. “If everything goes well, we hope that approval by ANVISA is granted in the first half of next year,” she says.
In January this year, the Brazilian Ministry of Health included the first vaccine against dengue, Qdenga, into Brazil’s public healthcare system (SUS). Manufactured by the Japanese laboratory Takeda, the vaccine is aimed at children aged 10 to 14.
The story above was published with the title “Protection against severe dengue” in issue 343 of September/2024.
Scientific articles
NOGUEIRA, M. L. et al. Efficacy and safety of Butantan-DV in participants aged 2–59 years through an extended follow-up: Results from a double-blind, randomised, placebo-controlled, phase 3, multicentre trial in Brazil. The Lancet Infectious Diseases. Aug. 5, 2024.
KALLAS, E. G. et al. Live, attenuated, tetravalent Butantan-Dengue Vaccine in children and adults. The New England Journal of Medicine. Feb. 1, 2024.
