One hundred and ninety-two patients received an expired injectable inactivated influenza vaccine between July 11, 2018, and March 29, 2019, according to the CDC.
Five things to know:
1. The reports were collected by the Vaccine Adverse Event Reporting System, a spontaneous reporting surveillance system. A total of 169.1 million doses of seasonal influenza vaccine were administered during the time period covered by the reports.
2. IIVs have an annual expiration date of June 30 for the pending influenza season, which is July 1 to June 30 of the following year.
3. Expired vaccines may be less effective against influenza, because the vaccine often includes different virus strains each year. Vaccine potency may also decrease with time.
4. Just 3.2 percent of reported expired vaccine injections resulted in adverse events, none of which were serious. The VAERS findings also indicate the expired IIV poses no added risks beyond those of the seasonal vaccine.
5. The CDC believes VAERS probably records only a small number of expired IIV injections, which means such errors may be more common than the data suggest.