Right now, the main strain causing flu in many places is an influenza A H3N2 variant, often referred to as the “subclade K” strain, which has been driving earlier and sometimes more intense flu activity this season.
Current dominant flu type
Most current surveillance reports describe influenza A, particularly the H3N2 subtype, as the predominant virus, with a specific offshoot called subclade K making up a large share of recent samples. Other flu viruses such as A(H1N1)pdm09 and influenza B are still circulating but at lower levels compared with H3N2 in many regions.
Why it matters
Seasons dominated by H3N2 have historically been associated with more severe illness and higher hospitalization rates in older adults and other vulnerable groups. Early analyses suggest this subclade K variant is somewhat different from the H3N2 strain in the current flu vaccine, but related enough that vaccination is still expected to provide at least partial protection and is still strongly recommended.
Local variation
The exact “flu going around” can differ by country, state, or even city, since some areas may see more H1N1 or influenza B than others at a given moment. Checking your local public health department or healthcare provider’s updates will give the most accurate picture for your specific area.