Summary of NACI statement of May 14, 2025: Updated recommendations on herpes zoster vaccination for adults who are immunocompromised

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• Overview
• What you need to know

Overview

• On May 14, 2025, the Public Health Agency of Canada (PHAC) released the National Advisory Committee on Immunization's (NACI) Updated recommendations on Herpes Zoster vaccination for adults who are immunocompromised. This guidance is based on current evidence and NACI expert opinion.
• Globally and in Canada, herpes zoster (HZ; shingles) is a significant public health problem. HZ is common, with the lifetime risk estimated to be as high as 30% in the general population. Advanced age and immunosuppression are the most important risk factors for developing HZ.
• On November 24, 2021, Health Canada authorized recombinant zoster vaccine (RZV, Shingrix^®) for adults 18 years of age or older who are or will be at increased risk of HZ due to immunodeficiency or immunosuppression caused by a known disease or therapy.
• Following a thorough review of the evidence on the risk of HZ in immunocompromised populations and the use of RZV in immunocompromised populations, NACI makes the following recommendations to inform RZV immunization programs for Canadian provinces and territories:
  • NACI now strongly recommends that individuals 18 years of age and older who are or will be immunocompromised should receive two doses of RZV to prevent herpes zoster and its associated complications.
    • A range of factors can impact the relative degree of immune suppression. Immunocompromising medical conditions and immunosuppressive drugs included in this list include primary immunodeficiencies, hematopoietic stem cell transplant, solid organ transplant, hematologic malignancies, solid tumor malignancies on immunosuppressive treatment, HIV infection, and chronic or ongoing immunosuppressive therapy. Please see the full NACI statement for more details.
• NACI will continue to monitor the evolving evidence and will update guidance as needed.

A PDF version of the Statement is available online on the NACI website and updates to the Herpes zoster (shingles) vaccine chapter will be published in the Canadian Immunization Guide (CIG) as soon as possible.

What you need to know

• HZ is a reactivation of varicella zoster (chicken pox) virus which causes a unilateral vesicular skin eruption but can be associated with more systemic complications including serious outcomes like postherpetic neuralgia and ophthalmological complications that can lead to blindness. HZ is more common among older adults and persons who are immunocompromised, and these groups are also more prone to severe disease and complications.
• Since 2018, NACI has strongly recommended that all immunocompetent adults 50 years of age and older should be offered the recombinant zoster vaccine (RZV) to prevent HZ.
• In 2021, Health Canada authorized RZV for adults 18 years of age or older who are or will be at increased risk of HZ due to immunodeficiency or immunosuppression caused by known disease or therapy.
• With this latest update from NACI, the committee is expanding the recommended populations to include younger age groups at high risk of shingles due to immunocompromising medical conditions.NACI now strongly recommends that individuals 18 years of age and older who are or will be immunocompromised should receive two doses of RZV to prevent HZ and associated complications.
• RZV is administered as a 2-dose schedule at a recommended interval of 2 to 6 months apart. However, if needed, for individuals who will be at increased risk of HZ due to immunodeficiency or immunosuppression (for example, individuals who are about to start immunosuppressive therapy), the second dose can be administered at a minimum interval of at least 4 weeks after the first dose, as these individuals will benefit from completing the series before being immunosuppressed. For optimal immune response, the 2-dose RZV series is recommended to be completed at least 14 days before the start of immunosuppressive therapy.
• RZV has been shown to be safe and effective in adults who are immunocompromised. Precaution should be used if considering use of RZV in pregnancy or breastfeeding given the absence of data on its safety for these groups.
• RZV can be given concurrently (i.e., same day) or at any time before or after other live or non-live vaccines.

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