El Niño increases concern about dengue

A bulletin from NOAA (National Oceanic and Atmospheric Administration, in free translation) projects the beginning of the El Niño phenomenon, with a second season for the end of 2026.

Scenario reinforces concern about possibilities of Aedes aegypti, mosquito that causes dengue fever, proliferates during seasons of heavy rain.

The concern is due to the increase in temperatures and storms that contribute to the proliferation of mosquitoes, responsible not only for dengue, but also diseases such as zika and chikungunya.

The infectious disease doctor and Director of the CCI (Infection Control) at Hospital e Maternidade Santa Joana, in São Paulo, Dr. Rosana Richtmann, points out that attention needs to be continuous in the population.

“This accelerates the mosquito’s life cycle, while changes in rainfall favor the emergence of breeding sites. Therefore, prevention needs to be constant, especially indoors, where most transmissions occur”, explains the doctor.

To protect against dengue and other diseases caused by mosquitoes, it is necessary to use insecticides, repellents and others, such as eliminating stagnant water, keeping water tanks closed and sanitizing containers that accumulate water.

SBP pest control executive, Letícia Pires, reinforces that attention must be redoubled in the coming months: “The combination of awareness, preventive habits and the use of effective solutions is essential to reduce the impacts of dengue in the country.”

What is El Nino?

The El Niño climate phenomenon is related to the irregular warming of surface waters in the Equatorial Pacific.

This warming alters tropical atmospheric circulation and influences the climate of various regions across planet Earth. Climatology has recognized this for a long time, but there are still difficulties in anticipating its exact intensity in each of its appearances and its regional impacts.

According to the bulletin, neutral conditions still prevail in the ocean, but the transition to El Niño is considered likely between May and July, with a 61% chance. By the end of 2026, the probability of occurrence of some level of the phenomenon exceeds 90%.

Dengue epidemic and vaccination

In 2024, Brazil faced the worst dengue epidemic in its history and recorded 4,013,746 probable cases of dengue, 3,809 deaths, in addition to 232 deaths under investigation.

As one of the main measures adopted, the Ministry of Health (MS) incorporated the rapid test for diagnosing dengue into the table of procedures funded by the SUS.

Vaccine suspension

The Ministry of Health stated last Monday (8) that it still there is no defined deadline for the conclusion of the investigation involving the dengue vaccine developed by the Butantan Institutewhich had its application temporarily suspended by the federal government.

Among the 42 serious adverse events, three cases caught the attention of health authorities and began to be investigated in depth.

The Ministry of Health states that theIt is not yet possible to conclude that the events were caused by the vaccine. According to the ministry, the temporal proximity between immunization and the appearance of symptoms does not prove a cause and effect relationship.

*Under the supervision of Thiago Félix, with information from Laura Toyama and Thomaz Coelho

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