Laboratory correlates of immunity to influenza

For some 30 years it has been a rule of thumb that antibody to influenza haemagglutinin, induced by natural infection or vaccination, is a universal and useful marker of immunity to influenza. It now seems important to re-examine this hypothesis. Knowledge of the mechanisms of acquired influenza immunity and correlations with measurable laboratory parameters is clearly of importance in understanding influenza epidemiology and vaccine-induced immunity. While immunity is certainly multi-factorial, involving both B and T cell responses, any comprehensive assessment is complicated by the capacity of the virus to undergo extensive and frequent antigenic variation. The aim of this workshop was