Rising H3N2 Influenza Activity: What You Need to Know and How to Stay Protected

Rising H3N2 Influenza Activity: What You Need to Know and How to Stay Protected

Health Authorities Urge Vaccination and Enhanced Hygiene as Flu Season Intensifies

November 26, 2025 – Influenza activity has entered a period of rapid increase across China, with the H3N2 subtype of influenza A currently dominating the seasonal outbreak. According to the latest data from the Chinese Center for Disease Control and Prevention (China CDC), H3N2 accounts for the vast majority of positive influenza specimens in both southern and northern provinces. Health experts are emphasizing that current outbreaks are driven by known pathogens at seasonal levels and have not detected unknown pathogens causing new infectious diseases.H3N2: Not a New Virus, but a Familiar FoeThe H3N2 subtype is not a new virus; it is a common seasonal influenza strain that has been circulating globally since 1968-4. A key characteristic of H3N2 is its tendency to undergo frequent "antigenic drift"—small changes in the virus's surface proteins. While these changes can enable the virus to spread more easily and cause seasonal epidemics, experts at the China CDC clarify that this does not mean the virus is becoming progressively stronger or more dangerous.

"The virus is prone to changes, known as antigenic drift, which is why we see seasonal flu outbreaks," said Dr. Peng Zhibin, a researcher at the China CDC. "However, the current situation remains at a seasonal epidemic level and does not indicate the virus is evolving to be stronger".Current Outbreak Characteristics and Vulnerable GroupsThis flu season is characterized by a significant shift from the previous year, which was dominated by the H1N1 strain-4. The current H3N2 wave started earlier than usual and is notably impacting children and adolescents.

Data show a significant increase in influenza outbreaks in kindergartens and schools, with the positive detection rate of the virus notably higher in the 5-14 age group than in others. For children, especially those under 5, infection carries a higher risk of complications such as laryngitis, bronchitis, and pneumonia.

Seniors are also at high risk. When H3N2 is the dominant strain, it often leads to more severe symptoms, longer recovery times, and increased hospitalizations and mortality among adults aged 65 and older-4.Vaccination: The Cornerstone of ProtectionHealth authorities consistently stress that annual vaccination is the most effective way to prevent influenza and reduce the risk of severe illness and death.

A common question is whether it's too late to get vaccinated now that the flu season has started. The answer from experts is a clear "no."

"Even though the flu season has already started, it is still meaningful to get vaccinated now," advised Dr. Qin Qiang, Chief Physician of the Respiratory Center at Beijing Children's Hospital. "The flu season will be long, and getting vaccinated still offers protective effects".

The China CDC confirms that the current seasonal flu vaccine, which is a multi-valent vaccine covering several strains including H3N2, maintains good effectiveness against circulating viruses. It is recommended for all individuals over 6 months of age-7."Vaccine + Hygiene": A Two-Layer Defense StrategyIn addition to vaccination, experts recommend a dual-strategy that combines vaccination with consistent personal hygiene habits. Key measures include:Practicing Good Hand Hygiene: Wash hands frequently with soap and water or an alcohol-based sanitizer.Wearing Masks in Crowded Places: Wearing a mask in crowded or poorly ventilated public spaces can reduce the risk of infection-2.Ensuring Indoor Ventilation: Regularly open windows for ventilation.Staying Home When Sick: If you develop flu-like symptoms, seek medical advice, wear a mask, and self-isolate at home to prevent spreading the virus to others.Treatment and Common MisconceptionsIf you or a family member contracts the flu, it is important to seek medical care promptly. For high-risk groups, initiating antiviral medication (like Oseltamivir) within 48 hours of symptom onset is most effective.

Experts also warn against a widespread misconception: using antibiotics to treat the flu is ineffective.

"Common 'anti-inflammatory drugs' like amoxicillin and cephalosporins are antibacterial agents," explained Dr. Song Rui, Chief Physician at Beijing Ditan Hospital. "They are effective against bacterial infections but do not work on viruses. The common cold and influenza are primarily caused by viruses, for which rest, hydration, and symptomatic treatment are the mainstays of care. Antibiotics should only be used under a doctor's guidance when a clear bacterial co-infection is present".Stay Informed, Stay Protected

As flu activity is expected to rise further in the coming weeks, adopting these protective measures is crucial for safeguarding personal and public health. For the latest updates, follow official health advisories from the China CDC and local health departments.