Flu Vaccine Provides Weaker Protection This Season

A recent report from the Centers for Disease Control and Prevention (CDC) has estimated that this season’s flu vaccine is reducing the risk of medical visits associated with influenza by 23%.

Flu vaccine effectiveness in previous seasons ranged from 10% to 60%, placing this season’s vaccine well on the lower end of the protection spectrum.

The CDC’s findings, published online on January 16, 2015, in its Morbidity and Mortality Weekly Report, highlight the importance of taking additional measures to prevent and treat the disease this season, including the use of influenza antiviral medications when necessary.

“Physicians should be aware that all hospitalized patients and all outpatients at high risk for serious complications should be treated as soon as possible with 1 of 3 available influenza antiviral medications if influenza is suspected, regardless of a patient’s vaccination status and without waiting for confirmatory testing,” says Joe Bresee, branch chief in the CDC’s Influenza Division. “Health care providers should advise patients at high risk to call promptly if they get symptoms of influenza.”

A vaccine’s effectiveness often depends on how well the flu viruses used to produce the vaccine “match” the predominant circulating viruses. According to the CDC, about 70% of circulating H3N2 viruses have differed from the current H3N2 vaccine virus, leading to this season’s low vaccine effectiveness.

Nevertheless, the CDC recommends that patients get their flu shots; despite its reduced effectiveness, the vaccine can still provide protection against some currently circulating viruses, as well as viruses that may circulate later in the season.