Serious Shingrix Side Effects Are Rare

More than a year after its introduction in the United States, Shingrix is living up to its clinical trial data that showed it to be safe. That’s the conclusion of just-released postlicensure safety surveillance report from the CDC.

The recombinant zoster vaccine (RZV) was approved by the FDA in October 2017. It received a preferred recommendation from the CDC’s Advisory Committee on Immunization Practices due to its reported efficacy rate of over 90%. Shingrix is recommended for adults age 50 and older, and is administered intramuscularly in two doses with an interval of two to six months between shots.

During prelicensure clinical trials, side effects of Shingrix were common. For example, 85% of 6,773 vaccinated study participants reported local or systemic reactions after receiving it; approximately 17% experienced a grade 3 reaction. However, the episodes were reported to be self-limited and resolved within a few days.

Serious adverse events-hospitalization or prolongation of existing hospitalization, life-threatening illness, permanent disability, congenital anomaly or birth defect, or death-were similar in both the RZV and placebo-control groups.

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Once Shingrix was licensed, the CDC and FDA began monitoring its safety in the Vaccine Adverse Event Reporting System (VAERS). During the first eight months of use, the manufacturer reports that approximately 3.2 million RZV doses were distributed. VAERS received a total of 4,381 reports of adverse events, or a rate of 136 reports per 100,000 doses distributed. Just 130 of the total reports were classified as serious. No unexpected patterns were detected.

The reported signs and symptoms were similar whether RZV was administered alone or in combination with other vaccines. The median interval between vaccination and the onset of side effects was one day.

Recipients aged 50 to 69 years reported a high proportion of systemic issues including fever, chills, and headache. Recipients over the age of 70 reported a high frequency of local symptoms such as erythema and pain at the injection site.

“Providers should expect such reactions in many of their patients and counsel them accordingly,” the study advises, adding that the effectiveness of a single dose of RZV has not been studied.

Additionally, there were 230 reports of vaccination errors, with 62% classified as errors of administration. In this group, three-quarters of the errors were described as incorrect route of administration, with the vaccine given subcutaneously rather than intramuscularly.

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The study’s authors conclude that the overall implications of RZV for public health practice are positive. “Healthcare providers and patients can be reassured by RZV’s initial post-licensure safety data,” they conclude. “Counseling patients to expect self-limited adverse reactions such as pain, swelling, and redness at the injection site, fever, chills, and body aches might ease concerns and encourage completion of the two-dose RZV series.”

The CDC and FDA continue to closely monitor the safety of RZV as its use increases and additional data become available from VAERS and from near real-time sequential monitoring in the CDC’s Vaccine Safety Datalink.

The report was published in the Feb. 1 issue of Morbidity and Mortality Weekly Report.