Individuals who were infected with influenza during the 2009 H1N1 pandemic but developed no symptoms or only mild ones tended, at the start of the pandemic, to have more immune T cells that specifically recognized conserved viral proteins, report researchers from the United Kingdom (Sridhar S et al. Nat Med. doi:10.1038/nm.3350 [published online September 22, 2013]).
The prospective cohort study included 342 individuals who were recruited before the onset of the second UK pandemic wave in 2009 and studied through the 2 consecutive influenza seasons, 2009-2010 and 2010-2011. The presence of preexisting T cells in individuals who were protected against severe illness points to a potential strategy for a universal flu vaccine. The authors suggest that such a vaccine might be designed to enhance T-cell responses, in contrast to current vaccines, which induce antibody responses.
Hampton T. Cellular Immune Response May Be Key to Universal Flu Vaccine. JAMA. 2013;310(17):1785. doi:10.1001/jama.2013.281694