Adult immunity to influenza is very closely tied to the strains of the virus that patients were exposed to as children. This means that older adults might have better immunity against strains that were more prevalent in the ’60s and ’70s, which may be going through a resurgence. New research hopes to exploit this exposure relationship to build a universal flu vaccine.

References:

Gostic KM, Ambrose M, Worobey M, Lloyd-Smith JO. Potent protection against H5N1 and H7N9 influenza via childhood hemagglutinin imprinting. Science. 2016 Nov 11;354(6313):722-726.

Devlin H. Will you get nasty flu this year? The year you were born can predict it, says study. The Guardian website. https://www.theguardian.com/science/2016/nov/10/will-you-get-the-flu-this-year-the-year-you-were-born-can-predict-it-says-study. Published online November 10, 2016.