Post-licensure safety data on recombinant zoster vaccine (Shingrix) is consistent with pre-licensure clinical trial data, although the CDC cautions that the immunization is still in the “early uptake period.”
The US Centers for Disease Control and Prevention (CDC) conducted post-licensure safety surveillance of recombinant zoster vaccine (RZV, Shingrix) and determined that its performance in the initial months after approval are consistent with what was observed during pre-licensure clinical trials.
The US Food and Drug Administration approved Shingrix, GlaxoSmithKline’s recombinant zoster vaccine (adjuvanted) against shingles (herpes zoster) for patients 50 and older in October 2017.
The approval was based on positive results from phase 3 trials, wherein Shingrix demonstrated greater than 90% efficacy against shingles across all age groups, as well as sustained efficacy over a follow-up period of 4 years in more than 38,000 patients, according to a GlaxoSmithKline statement.
Shingrix is administered intramuscularly and requires a 2-dose series, one received at baseline, with a follow-up vaccine in 2-6 months.
“During the first 8 months of use, when approximately 3.2 million RZV doses were distributed (GlaxoSmithKline, personal communication, 2018), [Vaccine Adverse Event Reporting System (VAERS)] received a total of 4381 reports of adverse events, 130 (3.0%) of which were classified as serious,” according to a new report by CDC investigators. “Commonly reported signs and symptoms included pyrexia (fever) (1034; 23.6%), injection site pain (985; 22.5%), and injection site erythema (880; 20.1%). No unexpected patterns were detected in reports of adverse events or serious adverse events.”
Elisabeth M. Hesse, MD, medical officer with the CDC Office of Immunization Safety and lead author of the report, said her office will continue to monitor Shingrix safety reports in both VAERS and the Vaccine Safety Datalink.
“Clinicians and their patients can be reassured by the initial post-licensure safety monitoring of the new shingles vaccine, Shingrix (recombinant zoster vaccine),” Dr. Hesse told Contagion®. “The safety findings are consistent with data from the pre-licensure clinical trials, with nothing new or unexpected. Clinicians should be advising their patients of expected adverse events following Shingrix, to include pain, swelling, and redness at the injection site, along with possible body aches, fever, and chills. Most of the reactions are self-limited and resolve in 2-3 days.”
The CDC briefing detailed 230 reports of vaccination errors, which could be contributing to described adverse events. A total of 62.2% of the vaccination errors were errors in administration, such as Shingrix being administered subcutaneously instead of intramuscularly.
There were also preparation errors reported. The vaccine comprises two vials—one containing the lyophilized antigen and the other containing the AS01B adjuvant suspension component (liquid)—which are to be mixed together before administration.
“Among 19 reports documenting product preparation errors, eight included administration of only the AS01B adjuvant; 11 reported mixing RZV lyophilized antigen with the wrong diluent, including sterile water (6), ZVL diluent (4), and an unspecified incorrect diluent (1),” the CDC report reads.
The agency is reassured by the early safety surveillance data but cautioned that Shingrix is still in the “early uptake period.”
“Understanding of the safety of RZV will advance as use increases and additional data become available from VAERS and from near real-time sequential monitoring in CDC’s Vaccine Safety Datalink,” the investigators concluded.