Brazil prepares to face an unprecedented dengue epidemic

“Madam, it is not advisable to leave so much water under your plants. “This attracts mosquitoes and does not help fight dengue.” It is the advice of a young soldier to a housewife in Ceilêndia, a city in the Federal District, the state where Brasilia is located. Currently, in this region, the average number of dengue cases is 10 times higher than in the rest of the country: in total, there are 120,874 infections and 12 deaths, according to official data from the Ministry of Health.

For this reason, The Department of Health of the Federal District has carried out a two-day training for 247 soldiers of the Brazilian Armywho are working together with Environmental Health Surveillance agents in search of sources of 'Aedes aegypti'the mosquito that transmits dengue.

Mosquito hunting is a recurring image that is repeated every time the data on contagion and death from dengue go up. But this year is on track to be one of the worst in recent decades. The data are alarming: only in the first month of 2024, 217,000 cases of dengue were registered, triple the number in the same period last year.

In addition, the Brazilian Government counted 15 deaths from this disease and 149 deaths remain under investigation. In 2023, there were a total of 41 deaths.

Read alsoBrazil will begin a vaccination campaign due to an increase in dengue

Faced with this situation, the Minister of Health, Nísia Trindade, announced on February 1 the launch of an Emergency Operations Center to control the dengue epidemic in Brazil. During a tripartite meeting at the headquarters of the Pan American Health Organization, in Brasilia, the minister called for national mobilization of states and municipalities. “Only with this union can we move towards protecting our population from dengue and, possibly, other viruses.” [como chikunguña y zika]”Trindade said.

The exceptional increase in dengue cases would be linked to a combination of high temperatures and intense rains, according to the Ministry of Health. The extreme heat and flooding have been caused by the meteorological phenomenon known as El Niño, after an atypical winter in Brazil, with temperatures well above average.

The result is that in the Federal District and in other Brazilian states, such as Minas Gerais and Acre, hospitals have already begun to fill.

In the city of Nova Iguaçu, on the outskirts of Rio de Janeiro, security guard Luiz Adriano da Costa became infected after his five children had dengue at the same time. The state of Rio de Janeiro registered 9,963 cases of this disease in the first three weeks of January. The data represents a growth of 587% compared to the same period in 2023.

The worst thing is that the peak of dengue in Brazil will arrive between April and May and can generate an unprecedented wave of hospitalizations.

The dengue virus is currently classified into four serotypes. This year, a significant resurgence of serotypes 3 and 4 of the virus is being detected in Brazil. This factor contributes to complicating the situation, given that these serotypes can cause reinfections in people who have already been infected with serotypes 1 and 2 in the past. When this happens, the clinical picture of the patients is usually much more serious.

“The mosquito 'Aedes aegypti' It is here to stay and it is only increasing. It began in 1980 in Rio de Janeiro and today it is present in practically all municipalities in Brazil,” highlights infectious disease specialist Antonio Carlos Bandeira, who in 2015 discovered the arrival of the Zika virus in Brazil.

“Trying to use transgenic mosquitoes (which neutralize the females of the Aedes aegypti) is currently impossible. Billions of transgenic mosquitoes would have to be released throughout the country. We really lost the time because we stay stopped. Every year we waited for the epidemic to go away. But the virus does not understand human appeals. He wants to continue. Came to stay. Our solution now is the vaccine. There is no other way,” she adds. This specialist highlights that dengue serotype 3 had not circulated in epidemic form in more than 15 years.

An unprecedented vaccine

The good news is that this month, the Ministry of Health will begin to apply the Qdenga vaccine, developed by the Japanese laboratory Takeda Pharma, in 516 of the 5,570 Brazilian municipalities. Initially, only adolescents between 10 and 14 years old are considered, since they represent the group with the highest number of cases of hospitalizations due to the disease.

Last October, the World Health Organization (WHO) recommended the use of this vaccine against dengue. Although vaccines against dengue already existed, that was the first time that the WHO agency recommended one.

01:48

The application criteria used in Brazil is purely scientific: only the cities with the most cases per 100,000 people have been included in the first contingency plan. For this reason. Sao Paulo, Brazil's largest city, was excluded from this first round of vaccination.

Qdenga contains live, low-intensity dengue viruses, capable of inducing immune responses against the four serotypes of the virus.. Its application provides for two doses, with an interval of three months between the first and the second.

“The vaccine protects 80% from symptomatic disease and 90% from hospitalization. It is a very high protection, especially for serotypes 1 and 2. In addition, there are follow-up studies of 57 months, that is, four and a half years, which show that this vaccine continues to protect mainly against hospitalization,” says Julio Croda, infectologist and researcher at the Oswaldo Cruz Foundation (Fiocruz).

This immunizer will be applied free of charge in the Brazilian Unified Health System (SUS), but since last year it can be found in private laboratories for a high price for the majority of the Brazilian population: up to 490 reais for each dose, that is, about 100 dollars.

With this, Brazil will be the first country in the world to offer this vaccine through the public health system.

“The vaccine is our hope. It is a fundamental instrument, but it is not a response to a moment of crisis. It is time to prevent and care. Dengue is a disease for which the SUS can act efficiently, preventing deaths,” said the Minister of Health.

The initial amount of doses applied by the Government is quite small due to the inability of the Japanese laboratory to supply more immunizers. “Producing companies need to work with long-term contracts, because it is necessary to expand factories for production. A company will never produce doses if there is no contract that guarantees the sale. Brazil recently decided to supply the vaccine and the existing doses for 2024 are these. And by 2025 we will also have a limited number of doses,” explains Croda.

To alleviate this shortage, The Butantan Institute of Sao Paulo, which produced a vaccine against Covid-19 in the middle of the pandemic, is already developing its own immunizer. It is expected that the data on its effectiveness will be sent for approval to the National Health Surveillance Agency (Anvisa) in the second half of this year and that the first doses can be applied in 2025. The Butantan vaccine has an efficacy of 79 .6%, very similar to that of Qdenga, according to an article in the New England publication. Researchers still do not know whether those who took the Takeda vaccine will be able to switch to the Butantan vaccine in the future.

What is clear, for now, is that Brazil will face a health emergency in the coming months that will test its public health system, considered the largest not only in Latin America, but in the entire world. Created in 1988, it serves around 190 million people, 80% of whom depend exclusively on this structure to treat their health.