Jakarta (ANTARA) - Starting the new year 2026, Indonesia and some countries are facing the fast-spreading strain of influenza A, or H3N2, which has been given the nickname ‘super flu’.Also known as Subclade K, this new branch of the familiar H3N2 influenza virus has recently been linked to a rise in flu cases in several countries, including the UK, the US, Australia, Japan, and parts of Europe.
Baca juga: Kasus flu meningkat di Lombok Timur, warga diminta waspadaAccording to the World Health Organization (WHO), seasonal influenza activity has increased worldwide in recent months, with a growing proportion of detected cases caused by influenza A (H3N2) viruses.
The WHO noted that while global influenza activity remains within expected seasonal levels, some regions have reported earlier-than-usual increases and higher activity than typically seen at this time of year.
Within Europe, subclade K was first detected in Norway, followed by the UK, where the influenza season started 4–5 weeks earlier than usual, according to the Vaccine Alliance (Gavi).
In the US, influenza activity was low before Thanksgiving but has since accelerated following holiday travel and school reopening, with the Centers for Disease Control and Prevention (CDC) reporting at least 2.9 million illnesses, 30,000 hospitalizations, and 1,200 deaths so far this season.
Most cases are due to influenza A (H3N2), with the subclade K now predominating.
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In Australia, the flu season—which typically runs from May to October—has been unusually prolonged, with infections linked to the H3N2 subclade K variant occurring towards its tail end.
While influenza notifications have been steadily declining in recent weeks, the virus continues to circulate.
Meanwhile, by the end of 2025, the Indonesian Health Ministry recorded 62 cases of subclade K spread across eight provinces, with the majority being women and children.
The findings were obtained from whole genome sequencing (WGS) examination completed on December 25, 2025, showing that subclade K was detected since August 2025 through the ILI-SARI sentinel surveillance system in various healthcare facilities.
In early October, the number of influenza cases experienced a significant spike, reaching 38 percent. This increase was largely influenced by seasonal changes, as influenza virus transmission tends to increase during cooler temperatures, particularly during the rainy season.
The WHO has confirmed that based on current epidemiological data, subclade K does not indicate increased disease severity, with symptoms generally similar to seasonal flu, including fever, cough, runny nose, headache, and sore throat.
However, the strain represents a notable evolution that warrants close monitoring.
Increase surveillance
The Health Ministry emphasized that by the end of December 2025, the situation related to the H3N2 subclade K variant in Indonesia remained ‘under control’ and showed no increase in severity compared to other influenza clades or subclades.
Nevertheless, the government will continue to strengthen surveillance, reporting, and preparedness to respond to developments in influenza activity in the country.
Strengthening integrated surveillance and responding quickly to developments in influenza activity are considered key to addressing the spread of this disease.
Strict surveillance, covering the number of cases, the severity of symptoms, and transmission patterns, must continue, in addition to preparing health facilities to anticipate an increase in cases.
By strengthening upstream detection through a measurable surveillance system, the government can make targeted, data-based decisions.
According to Prof. Masdalina Pane, research professor in epidemiology and biostatistics at the National Research and Innovation Agency (BRIN), outbreak control relies heavily on optimizing the Early Warning and Response System. In theory, this system works like a radar that monitors epidemiological thresholds.
Strengthening surveillance functions at selected healthcare service points is also crucial to maintain the sensitivity of case detection, she added. With quality data, the government can precisely measure the level of this variant category.
However, government efforts must also go hand in hand with increased public awareness to maintain health and strengthen the immune system.
Therefore, people are encouraged to strengthen their immune systems by practicing clean and healthy living habits, washing hands, getting enough rest, and eating nutritious food.
Through synergy between surveillance and individual discipline, it is hoped that the risk of super flu can be prevented.
Vaccination
The Health Ministry also emphasized that the current flu vaccine remains effective in reducing the risk of serious illness, hospitalization, and death due to subclade K variant.
It is in line with the early estimates published in Eurosurveillance that suggest that the vaccine is 72-75 percent effective in children and adolescents, while it is around 32-39 percent effective in adults.
Thus, administering annual influenza vaccinations—especially to vulnerable groups, including the elderly, pregnant women, and those with comorbidities—is crucial to protect ourselves from exposure to the virus.
In order to minimize transmission, someone who has flu symptoms—including a high temperature, cough, and feeling tired or achy—should try to minimize contact with others, consider wearing a face covering, and take medication to relieve symptoms.
