Colombia Confirms First Case of H3N2 Influenza

Colombia’s Ministry of Health and Social Protection has confirmed the first detection of the influenza A(H3N2) virus in Colombia. The imported case was identified in a patient who recently traveled internationally on a cruise ship departing from Miami.

The finding, coordinated with the National Institute of Health (INS), aligns with a forecast issued by health authorities on Dec. 18. The patient presented with mild respiratory symptoms, including fever, runny nose (rhinorrhea), and cough.

Initial identification was performed by the Genomics Group of Antioquia, and subsequently confirmed through molecular testing (FilmArray respiratory panel) by the INS’s Directorate of Research in Public Health.

Colombia’s health authorities say there is no surge in severity detected 

Colombian health authorities emphasized that the detection of this variant has not coincided with an increase in the severity of respiratory infections, hospitalizations, or deaths in the country.

The H3N2 variant has been monitored globally by organizations such as the Pan-American Health Organization (OPS) and the European Centre for Disease Prevention and Control (ECDC) due to mutations in the hemagglutinin protein, which facilitates the virus’s entry into human cells. 

While cases have risen in the Northern Hemisphere, particularly in Europe, the United States, and Australia, current data does not suggest this variant causes more severe illness than previous strains. “Viruses mutate to subsist, and that happens with the flu every year. It is not a phenomenon different from what is usually observed during influenza seasons,” explained infectious disease specialist Carlos Arturo Alvarez Moreno to local outlet El Tiempo.

Authorities say the influenza vaccine remains effective in preventing complications from the A/H3N2 strain

The Ministry of Health reiterated that the influenza vaccine available in Colombia for 2025 contains the A/H3N2 strain and remains effective in preventing severe complications, hospitalizations, and death, despite the genetic differences of the new subclade.

Vaccination is prioritized for specific groups, including children aged 6 to 23 months, adults over 60, pregnant people from the 14th week of gestation, health care workers, and individuals with chronic conditions such as diabetes, asthma, or cardiovascular disease.

To curb transmission during the respiratory virus season, authorities recommend: Frequent hand washing, especially upon arriving home and before eating, and keeping closed spaces such as schools and public transport well-ventilated. Mask use is also recommended for those with respiratory symptoms, particularly when around vulnerable populations. Isolation, symptomatic individuals should isolate for at least three days and avoid sending sick children to school.

The country’s epidemiological surveillance system remains active to detect early changes in virus behavior, but authorities urged the public to avoid panic, clarifying that this scenario is not comparable to the COVID-19 pandemic.