Review of the initial post-marketing safety surveillance for the recombinant zoster vaccine

Background: The adjuvanted recombinant zoster vaccine (RZV) received its first marketing authorization in October 2017, for prevention of herpes zoster in individuals aged ≥50 years.

Methods: We summarized safety information, following RZV administration, received by GSK via spontaneous adverse event (AE) reports submitted by healthcare providers, vaccine recipients and other reporters. Observed-to-expected (O/E) analyses were performed for selected outcomes: reports of death, Guillain-Barré syndrome and Bell's palsy. Standard case definitions were used to assess individual case reports. Data mining, using proportional reporting ratio and time-to-onset signal detection methods, was employed to identify RZV-AE pairs with disproportionate reporting or unexpected time-to-onset distribution.

Results: Between October 13, 2017 and February 10, 2019, an estimated 9.3 million doses were distributed and GSK received 15,638 spontaneous AE reports involving RZV. Most reports were classified as non-serious (95.3%) and originated from the United States (81.7%), where the majority of doses were distributed. Among reports with age or sex reported, individuals were mainly 50-69-year-olds (62.1%) and female (66.7%). Of all reports, 3,579 (22.9%) described vaccination errors, of which 82.7% were without associated symptoms. Of all vaccination error reports, most described errors of vaccine preparation and reconstitution (29.7%), inappropriate schedule or incomplete course of administration (26.7%), incorrect route of administration (16.4%), and storage errors (12.9%). The most commonly reported symptoms were consistent with the known RZV reactogenicity profile observed in clinical trials, including injection site reactions, pyrexia, chills, fatigue, headache. O/E analyses for selected outcomes and data mining analyses for all reported AEs did not identify any unexpected patterns.

Conclusions: Review of the initial data from the post-marketing safety surveillance showed that the safety profile of RZV is consistent with that previously observed in pre-licensure clinical trials. Other studies are ongoing and planned, to continue generating real-world safety data and further characterize RZV.