Incidence data

Incidence data for seasonal influenza viruses A/H3N2, A/H1N1, B/Vic and B/Yam. Each row represents a USA winter influenza season. The column "flu" gives the frequency of influenza positive isolates from all isolates tested. The columns "typeA" and "typeB" give the relative frequencies of influenza A and influenza B in samples that tested positive. The columns "subtypeH3", "subtypeH1", "subtypeH1pdm" give the relative frequencies of A/H3N2, A/H1N1 and pandemic A/H1N1 among type A samples. The columns "subtypeVic" and "subtypeYam" give the relative frequencies of B/Vic and B/Yam among type B samples. The column "ili" gives the influenza-like illness (ILI) frequency over the same season.