Question: what are the 2019 flu strains?
Answer: Two flu strains, peaking at different times At the start of the 2018-2019 flu season, the dominant circulating strain of virus was A(H1N1), and the flu vaccine was well matched to it. The more virulent strain, A(H3N2), was present at a low level until mid-January, when its incidence started sharply increasing.