Vaccination in adults at-increased risk of herpes zoster in Canada: insights from a multidisciplinary panel consensus.

Background: Risk of herpes zoster (HZ) increases with age (notably at ≥50 years), with greater risk also apparent in immunocompromised populations. The use of the recombinant zoster vaccine (RZV) in adults aged ≥50 years is established in Canada. However, while licensed RZV use was expanded in 2021 to include individuals ≥18 years of age who are or will be at increased risk of HZ due to immunodeficiency or immunosuppression caused by known disease or therapy, there remains some uncertainty for clinicians regarding which patients should be offered vaccination.

Research design and methods: To assist decision-making, a Canadian multidisciplinary panel was convened to develop guidance on the use of RZV in at-risk adults aged ≥18 years through a consensus approach, defined as ≥75% of the experts rating their agreement.

Results: The panel concluded that RZV should be offered to all at-risk individuals aged ≥18 years who are or will be at increased risk of HZ due to disease or therapy, in line with the licensed indication. This includes those with chronic medical conditions at greater risk of HZ (e.g. COPD, diabetes). Decisions should be individualized based upon patient assessment and shared clinical decision-making. Where possible, the two-dose vaccine series should be given at the earliest opportunity.

Conclusions: Findings from this expert consensus provide guidance on the use of RZV in individuals ≥18 years at increased risk of HZ. Our views complement updated national recommendations for immunocompromised patients issued in May 2025.