Healthcare providers may be confusing administration and storage procedures for the newly approved recombinant zoster vaccine (RZV; Shingrix, GlaxoSmithKline) and the live attenuated zoster vaccine (ZVL; Zostavax; Merck), according to the latest Morbidity and Mortality Weekly Report.
Between October 20, 2017 and February 20, 2018, the Vaccine Adverse Event Reporting System (VAERS) received 155 reports involving RZV, with 13 (8%) involving an administrative error. Nine documented the vaccine being delivered subcutaneously rather than the approved intramuscular route; 8 of these errors led to injection site reactions. Two individuals were given information relating to ZVL instead of RZV, meaning they were unaware of the need to return for the second RZV dose.
RZV is approved by the Food and Drug Administration (FDA) and is preferentially recommended by the Centers for Disease Control and Prevention (CDC)’s Advisory Committee on Immunization Practices (ACIP) for the prevention of herpes zoster in adults ≥50 years, although the report did include two cases of individuals under 50 receiving the vaccine. The other cases included administration of RZV after incorrect frozen storage, administration of only the adjuvant component without reconstitution with the vaccine antigen, and administration of RZV instead of an intended varicella vaccine (Varivax; Merck).
“Early monitoring indicates that vaccine providers might confuse administration procedures and storage requirements of the older ZVL and the newer RZV,” concluded the authors.
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