Transient increased risk of shingles post Shingrix vaccination: Self-controlled case series analysis.

Following the introduction of a funded recombinant shingles (RZV, Shingrix®) vaccination program in ≥65 years in Australia, clinician reports of shingles presentations shortly after vaccination emerged. We investigated whether there was an increase in shingles risk immediately post RZV vaccination in South-eastern Australia. Two independent datasets- a general practice dataset and a statewide linked dataset- were analysed separately using self-controlled case series analyses (SCCS) with 21-days post-vaccination as the risk window. The observation period was 1 January 2023 to 30 April 2025. Adults ≥18 years old were included, with analyses stratified by age (<65 and ≥65 years) and sex. We calculated the rate of incident shingles in time periods relative to vaccination, along with attributable risk and the risk of postherpetic neuralgia (PHN). The primary care SCCS analysis found an 11-fold increase (Risk Incidence [RI] 10·96, 95% CI 10.34, 11.62, p <0·0001) in shingles presentations within 21 days post-dose 1 of RZV vaccination in adults ≥65 in the general practice dataset only. No increase was detected in younger adults. Following dose two the risk of shingles presentations was reduced in all age groups. Vaccine recipients had an 73% reduction in shingles following 2 doses. PHN risk was not increased. There is a transient increase in shingles presentations shortly after dose one of RZV vaccination in adults ≥65 years of age; however, these cases are likely to be mild and there is clear evidence of vaccine effectiveness after the completion of two doses.