Khaberni - The World Health Organization has warned of the "K" (K) subtype of the H3N2 influenza virus variants, with its spread to 34 countries around the world.
According to the organization, seasonal influenza activity has seen a global increase over the recent months, with type (A) influenza viruses diagnosed in the majority of recorded cases.
The World Health Organization reported that the monitoring of this strain has seen a rapid increase since August 2025, based on genetic sequencing data shared through the "GISAID" platform (Global Initiative on Sharing All Influenza Data).
The organization added that the currently available epidemiological data does not indicate an increase in the severity of disease associated with this strain, although its spread reflects the ongoing evolution of seasonal influenza viruses.
The "K" Subtype
The World Health Organization considers the "K" subtype a genetically distinct group of type (A) influenza viruses.
These viruses have undergone genetic changes compared to the related J.2.4 viruses, including several changes in the amino acids of the hemagglutinin protein, which is responsible for the virus's attachment to human cells.
Influenza viruses typically undergo such changes over time, and global monitoring systems track them to assess their potential impact on transmission speed, disease severity, and vaccine effectiveness.
More than 34 Countries
The World Health Organization announced monitoring the "K" subtype since the beginning of August 2025, especially in Australia and New Zealand.
Since then, the organization has detected the same strain in more than 34 countries over the past six months, including the United States.
According to the organization, most regions of the world are seeing an increase in the detection of this strain, except for South America so far, with waves appearing in some European and Asian countries.
Prominent Symptoms
The World Health Organization confirmed that there is no evidence that infections with the "K" subtype cause symptoms different or more severe than those caused by other seasonal type A(H3N2) influenza viruses.
Common symptoms of seasonal influenza include fever, cough, sore throat, runny or stuffy nose, muscle or body aches, headache, and fatigue.
The severity and duration of symptoms vary depending on age, overall health condition, and the strength of each person's immune system.
Influenza Vaccines
The World Health Organization indicated that initial estimates confirm that seasonal influenza vaccines continue to provide protection against severe cases and hospitalizations in children and adults.
The organization added that even if there are genetic differences between the circulating viruses and vaccine strains, vaccination may reduce the risk of serious complications.
Monitoring Influenza Activity
On the other hand, the World Health Organization stated that it continues to monitor global influenza activity and virus evolution, alongside supporting countries in monitoring efforts and updating guidelines as new data emerge.
Health experts noted that changes in circulating influenza viruses are expected each season, and they are regularly assessed through international monitoring systems.
