PAHO warns of increased risk of dengue outbreaks due to circulation of DENV-3 in the Americas – PAHO/WHO
Washington, DC, February 10, 2025 (PAHO) -The Pan American Health Organization (PAHO) has issued an epidemiological alert about the highest risk of dengue outbreaks in the Americas, attributed to the growing circulation of the DENV-3 serotype in serotype in several countries in the region. The PAHO urges countries to strengthen their surveillance, early diagnosis and clinical management to address potential increases in dengue cases.
Dengue, transmitted by the Aedes Aegypti mosquito, has four serotypes: DENV-1, DENV-2, DENV-3 and DENV-4. Immunity against a serotype only provides life protection against that specific serotype, which means that subsequent infections with other serotypes can increase the risk of serious forms of the disease. The appearance or increase of a serotype that was not previously predominant in a region can lead to an increase in cases due to greater susceptibility to the population.
The denv-3 situation in the region
The DENV-3 serotype has been identified in several countries of the Americas, including Brazil, Colombia, Costa Rica, Guatemala, Mexico and Peru. In 2024, Argentina reported its circulation, marking the introduction of this serotype in the country. In the same year, Brazil and Colombia reported an increase in cases associated with DENV-3, particularly among children, and has also been detected in other countries in Central America and the Caribbean. This serotype has been linked to serious forms of the disease, even in primary infections, which raises concerns about its potential impact on public health.
The resurgence of DENV-3, after prolonged absence in certain areas of the region, increases the vulnerability of populations that have not been previously exposed to this serotype.
Current situation and recommended measures
In 2024, the region of the Americas reported more than 13 million cases of dengue, of which 22,684 were classified as severe (0.17% of the total) and 8,186 resulted in deaths (mortality rate of cases of 0.063%). In the first weeks of 2025, 23 countries and territories in the region reported a total of 238,659 cases, with the majority concentrated in Brazil (87%), followed by Colombia (5.6%), Nicaragua (2.5%), Peru (2.5% ), and Mexico (2.5%). Of these cases, 263 were serious, and 23 people died as a result of the disease.
Paho recommends that countries strengthen vector control measures, improve diagnostic capacity within medical care systems and guarantee early and adequate treatment for patients to prevent serious complications. Public education campaigns are also essential to reduce exposure to mosquito vectors and eliminate reproduction places.
The role of vaccination and monitoring
With respect to vaccination, according to the evidence generated by the manufacturer and published in the main study of phase 3, the TAK-003 dengue vaccine, used in some countries in the region, has shown less protection against DENV-3 , especially in children without history history. of infection. This highlights the need to guarantee safe vaccination and maintain continuous monitoring of adverse events potentially attributable to vaccination.
Paho is closely monitoring the evolution of the circulation of DENV-3 together with the other serotypes, and will continue to support countries in the implementation of effective control and response measures to possible outbreaks. It is essential that health systems are prepared to handle the expected increase in cases and mitigate the risk of serious complications associated with this disease.
