As an H5N1 pandemic looms over us, the CDC is strongly recommending flu shots while urging farmworkers to get vaccinated. This year’s shot is trivalent, meaning it contains vital proteins from Flu A strains H1N1, H3N2, and one Flu B virus. In the past, they’ve used a quadrivalent vaccine, but this year they excluded a Flu B strain they believe to have been essentially eradicated (because of enhanced protection measures like masking and clean air). All of this made me wonder how well a seasonal flu vaccine protects against a novel strain. The CDC’s official answer is that it doesn’t. However, there’s a big but they won’t say…
Studies suggest otherwise.
Normally, your immune system only develops a memory of specific antigens. Your immunity to one virus doesn’t transfer to others. However, in the case of flu viruses, cross-protection can happen. In fact, recent research covered in Nature stresses the need for universal flu vaccines that generate mucosal im…