Peru Confirms First Cases of Influenza A H3N2 Subclade K, Declares National Alert
Peru’s Ministry of Health has confirmed the detection of the first cases of influenza A H3N2 subclade K within the country, identifying the virus in two minors residing in Lima. The discovery prompted the immediate activation of surveillance, diagnosis, and monitoring protocols as preventative measures.
A senior official explained that the infections are considered seasonal influenza and were registered in the capital city, which accounts for approximately one-third of Peru’s total population. This confirmation followed the declaration of a national epidemiological alert issued the previous day.
“Both cases are currently being managed at home and have not presented with any major health risks,” the official stated, emphasizing the importance of protecting the nation’s most vulnerable populations.
According to César Munayco, director of the National Center for Epidemiology, Prevention and Disease Control (CDC Peru), the virus subclade originated in the United States and Australia and is currently circulating in at least 32 countries globally. Recent data indicates an increase in circulation, particularly in Europe and several East Asian nations.
The Pan American Health Organization (PAHO) and the World Health Organization (WHO) released an information note detailing the evolving situation. The organizations reported that influenza activity in Europe began earlier than usual, with subclade K accounting for nearly half of the viral sequences reported between May and November 2025. Importantly, to date, no significant changes in the clinical severity of the virus – including hospitalization rates, intensive care admissions, or deaths – have been documented.
PAHO and WHO are urging member states to prioritize several key actions. These include close monitoring of the virus’s evolution through genomic surveillance, maintaining high vaccination coverage rates, ensuring timely treatment for cases, and preparing for potentially earlier or more intense influenza activity during the 2025-26 influenza season.
The emergence of this new subclade underscores the ongoing need for vigilance and proactive public health measures to mitigate the spread of influenza and protect communities worldwide.
