Whereas adaptive immunity is thought to be a response to specific bacteria, viruses, fungi and parasites, innate immunity has always been seen as the body's general response to all threats of disease.

Analyses of infection rates in modern seasonal flu epidemics suggest that with age comes a subtle buildup of immunity to flu viruses in general.

Now a team of researchers from the Ragon Institute of Massachusetts General Hospital, MIT and Harvard has revealed a new effect that contributes to this gene’s ability to confer immunity.