Flu vaccines are formulated each year to be effective against the flu strains most expected to hit that season. But this year, state health department epidemiologist Jessica Rigler says the H3N2 strain is mutating, making the vaccine ineffective against it about 50 percent of the time.
“Typically in years when we have H3N2 viruses circulating we do see a higher number of hospitalizations and an increased mortality,” Rigler said.
Rigler says even though the vaccine is not 100 percent effective, it is still the best protection you have against the flu. Fortunately, she says there is no sign of the H3N2 strain in Arizona so far.