Colombia has confirmed the first case of the influenza A(H3N2) virus. According to a statement from the Ministry of Health, this is an “imported case with a history of international travel to the United States.” The detection was carried out in the department of Antioquia and, until now, “an increase in acute respiratory incidents” has not been recorded.
The “superflu,” as it is also known, has become famous in recent weeks for incorporating a series of mutations that have caused a surge in flu cases. In countries like Mexico and Chile, alerts and calls to take care of yourself were launched at the beginning of December, while in Spain, which entered the epidemic phase, it was detected at the end of October.
Infections caused by this flu can be prevented in the same way as other flu subtypes. The Ministry of Health recommends vaccination as an effective protective measure and recalls that the vaccine is available throughout the country.
What is H3N2 flu?
It is one of the viruses responsible for seasonal influenza, which, year after year, causes an increase in respiratory illnesses that coincides with the arrival of autumn and winter. Along with the H1N1 flu, H3N2 is one of the most circulating viruses during the season. “Influenza viruses have a biological characteristic that causes them to undergo mutations and changes. From time to time these accumulate and produce more changes and generate different characteristics from the others. Every year there is one influenza virus that predominates and what happens is that different epidemiological surveillance systems in several countries have warned that the predominant virus is an AH3N2 type virus and all the surveillance protocols say that it must continue to be studied,” said Mauricio Rodríguez Álvarez, spokesperson for the risk program, explains to this newspaper. UNAM epidemiological studies.
On December 12, the Pan American Health Organization (PAHO) called on member countries to promote vaccination with a focus on the elderly and to strengthen surveillance of the virus in the region, given its recent circulation in Europe, Asia, the United States and Canada: “Health authorities in these countries have not reported significant changes in clinical severity, but historically, seasons dominated by the A(H3N2) virus are generally associated with a greater impact on the elderly”, explains the OPS in a press release.
This is not a pandemic threat
Rodríguez is categorical when he assures that there is no point of comparison between the effects of the H3N2 flu and the emergence of SARS-CoV-2, which caused the covid-19 pandemic that began in March 2020. “We are not facing a virus that leaves us without protection like the covid virus. “The H3N2 virus is not a pandemic threat, because we have many elements that help us reduce its impact: the first is the sentinel system, epidemiological surveillance of respiratory viruses; the second, diagnostic tests; the third, clinical suspicion, the knowledge of doctors; the fourth is oseltamivir as a specific antiviral for patients; and the fifth is vaccination for several years against seasonal flu, which generally has a level of protection.”
In light of current data, Rodríguez explains that there is no evidence that H3N2 causes more severe illness or that it affects any age group other than usual. Although the WHO says the flu remains within expected ranges globally, the high circulation of the virus suggests it is slightly more transmissible. “The important thing is that it is a seasonal virus that is monitored and what we need to do is avoid contagion in the community,” he explains. From the UNAM research program on epidemiological risks of which he is part, Rodríguez emphasizes the need to prevent infections with the same prevention measures popularized during the covid-19 pandemic, such as the use of face masks in case of symptoms of respiratory illness and vaccination against influenza to reduce the risk of serious illness and hospitalization.
Symptoms and treatment
Like other viruses that cause respiratory illnesses, influenza caused by H1N1 or H3N2 manifests itself with fever, cough, sore throat, muscle pain and general fatigue. Rodríguez indicates that even if a test is necessary to know which respiratory illness it is, “in practice, it is the same flu: neither the patient nor the attending physician makes a difference if the virus is H1N1 or H3N2 from before, or H3N2 from the K subclade”, he assures. “It’s the same route of infection, the same incubation period of one or two days; the same clinical manifestation with fever, cough, joint pain, headache; the diagnosis is made with the same type of tests and the same treatment is administered, which is oseltamivir, the specific antiviral against the influenza virus.”
H3N2 in Colombia
The H3N2 virus is an old acquaintance of the Ministry of Health and Welfare and the National Institute of Health. In 2019, for example, the circulation of H3N2 was 12.8%, in 2024 it was 4.9% and this year, until week 48, the government reported a circulation of 4.4%. Colombia, which is part of the Andean region, experiences influenza circulation throughout the year. In Europe, the K subclade represents almost half of the viruses detected between May and November 2025, according to the institution.
Who should be vaccinated
- According to the Ministry of Health, the flu vaccine “reduces hospitalizations and deaths from this disease” and is particularly recommended in the following groups:
- Infant population aged 6 to 23 months
- People over 60 years old
- Pregnant women from the 14th week of pregnancy
- Population with risk diagnoses of 24 months and adults.
- Human talent in health
- People with chronic illnesses such as asthma, COPD, cardiovascular disease, kidney disease, liver disease, diabetes, obesity, cancer, HIV or other conditions that compromise the immune system.
- Parents and partners of people under 18 with cancer
Among the series of recommendations put forward by the Health portfolio are frequent hand washing, particularly after coughing or sneezing; the use of face masks in people with respiratory symptoms and adequate ventilation of enclosed spaces
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