Health officials in Costa Rica have confirmed the presence of a new influenza A(H3N2) variant, subclade K, as cases of respiratory illnesses rise during the holiday season. The Ministry of Health reports that the virus started spreading earlier than expected this year, prompting calls for stronger protective steps among residents.
The World Health Organization indicates that influenza activity picked up in August across multiple countries, with subclade K among the strains identified. In Costa Rica, the Costa Rican Institute for Research and Teaching in Nutrition and Health analyzed samples from September to November and verified the variant’s circulation starting October 14. Seven cases have surfaced so far, each showing mild symptoms like fever, cough, and fatigue, with no need for hospital stays.
Minister of Health Mary Munive noted that while the cases remain light, seasons led by A(H3N2) strains often hit older adults harder. “No rise in serious outcomes or deaths has appeared yet,” she said, “but we must act to shield those at higher risk.”
Recent data shows a broader uptick in influenza A, with 249 cases logged in the past three weeks alone. Most involve the H3 subtype, though not all have full subtyping. This aligns with global patterns where subclade K has grown quickly in Europe and Asia, making up a large share of A(H3N2) detections without worsening illness overall.
The Pan American Health Organization stresses that the current vaccine still guards against severe effects, even with the variant’s genetic shifts. Costa Rica’s 2025 vaccination drive reached 85 percent overall, but only 32.3 percent of children aged six months to eight years got the shot. Officials push for catching up, especially for kids, seniors, and people with health conditions.
With vacations and gatherings underway, the Ministry advises simple habits to curb spread. Wash hands often, cover coughs with an elbow or tissue, and skip crowded spots if possible, particularly with young kids or elders. Keep distance from anyone showing signs of illness and choose open-air events over indoor ones.
Further tips include steering clear of self-treatment for children and seniors, avoiding smoke from cigarettes or vapes, and supporting breastfeeding for infants under six months. People with fever, cough, diarrhea, or vomiting should stay home from events. Seek care starting at local clinics if symptoms arise. These measures not only tackle flu but also cut risks from other seasonal bugs, like stomach issues.
