Brazil could experience type 3 dengue epidemic in 2024 – 10/03/2023 – Health

The likelihood of the resurgence of serotype 3 of the dengue virus in Brazil raises awareness of an epidemic in 2024, “important and with deaths”, according to Kleber Luz, coordinator of the Arboviruses Committee at SBI (Brazilian Society of Infectious Diseases) and consultant for arboviruses at PAHO (Pan American Health Organization), branch of the WHO (World Health Organization) in the Americas.

“Dengue serotypes 1 and 2 will predominate in Brazil in 2023. Type 3 is very present in Mexico, in Central America, and it has already been found in the North of the country. There is a chance of a more important epidemic, with deaths”, he highlights .

The report spoke to the specialist —who is also a member of the WHO arbovirus technical group and professor at the Federal University of Rio Grande do Norte— during the 23rd Brazilian Congress of Infectious Diseases (Infecto2023), held in Salvador (BA), from 19 to September 22.

For more than 15 years, dengue serotype 3 has not caused epidemics in Brazil. Its return is risky because of the population’s low immunity.

The dengue virus has four serotypes. When an individual is infected by one of them they acquire immunity against that virus, but are still susceptible to the others. There is a danger of severe dengue, which occurs more frequently in people who have already had the disease and are infected again, with another serotype. This is what can happen with type 3 infection.

For Luz, in this scenario, the main concern of health authorities should be management.

“The state and municipal health departments, and the ministry [da Saúde] They will need to prioritize training doctors and nurses to recognize serious forms of dengue and intervene. We are in the month of September and we already have almost a thousand deaths from dengue in the country. You can solve everything in medicine, except death,” he says.

According to the expert, an education program is also necessary for people to avoid mosquito breeding sites.

“Popularly, I have seen little campaign. Not only for dengue, but also for HIV, for vaccination. It seems that there has been a slowdown in these measures. The third point is vaccination. There is already a vaccine. Perhaps it would be interesting to recommend vaccination as an action to public service”, he argues.

Two dengue vaccines have been approved for commercial use in Brazil – Dengvaxia (Sanofi Pasteur) and Qdenga (Takeda Pharma), but neither is incorporated into the SUS (Unified Health System). Both are chimeric, that is, attenuated. They have distinct protective effects against serotypes – Takeda is greater for 1 and 2; Sanofi, smaller for the 2.

Sanofi’s has a framework of the yellow fever virus, with fragments of serotypes 1, 2, 3 and 4. It is recommended for people aged 9 to 45, but the indication only applies to those who have been previously infected by one of the subtypes. It is administered in three doses, three months apart.

Studies carried out by the producing laboratory showed the risk that people who have never had the disease will develop more serious forms of dengue if they are infected by the mosquito. Aedes aegypti.

Takeda’s has the attenuated dengue 2 framework, in this case, with proteins from 1, 3 and 4. It is aimed at individuals aged 4 to 60 years, and administered in two doses three months apart. More studies are needed to analyze serotypes 3 and 4.

“There are still gaps in the decision to use these vaccines. If I have dengue now, when can I take the first dose? And if I take the first dose and have dengue in 90 days, when can I take the second? So, these are questions that need to be answered.

Another important action, according to the researcher, is to stimulate Wolbachia, the bacteria that infects mosquitoes. “When you control the mosquito, you control dengue, zika and chikungunya. And pregnant women should use repellent because of zika. Sooner or later we will have cases. Microcephaly is the biggest problem in relation to arboviruses”, concludes the doctor.

In 8 months, Brazil records 946 deaths from dengue

In Brazil, until September 2, 2023, 1,530,940 cases of dengue were registered and an incidence rate of 753.9 cases/100 thousand inhabitants. In the same period last year, the country had 1,313,805 cases — a rate of 647.0 cases/100 thousand inhabitants.

The World Health Organization (WHO) considers that rates above 300 cases per 100,000 inhabitants indicate an epidemic situation — according to the researcher, this year, caused by serotypes 1 and 2.

Regarding deaths, in the same period, there were 946 in 2023 and 960 last year.

The reporter traveled at the invitation of the Brazilian Society of Infectious Diseases.