Influenza surveillance 1972-75. By the Public Health Laboratory Service Standing Advisory Committee on Influenza.

The surveillance programme described in an earlier report was used to monitor outbreaks of influenza in three successive winters. Influenza virus A was active in all of them, but the only major outbreak of influenza B was in 1973--4. The highest incidence of influenza A was in the 0--4 age group in all three winters, but schoolchildren bore the brunt of infections by influenza virus B.