Summary of NACI statement of March 13, 2025: Updated guidance on respiratory syncytial virus (RSV) vaccines for older adults including the expanded use of RSVPreF3 for individuals 50 to 59 years of age and use of the new mRNA-1345 vaccine

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• Overview
• What you need to know

Overview

• On March 13, 2025, the Public Health Agency of Canada (PHAC) released the National Advisory Committee on Immunization's (NACI) Updated guidance on RSV vaccines for older adults including the expanded use of RSVPreF3 for individuals 50 to 59 years of age and the use of the new mRNA-1345 vaccine. This guidance is based on current evidence and NACI expert opinion.
• There are now three vaccines available to protect older adults from RSV in Canada:
  • RSVPreF3 (AREXVY, GSK) was authorized on August 4, 2023, to protect adults 60 years of age and older with a recently expanded age indication on November 1, 2024, for adults 50 to 59 years of age at high risk of RSV disease.
  • RSVpreF (ABRYSVO^TM, Pfizer) was authorized on December 21, 2023, to protect adults 60 years of age and older. This formulation is also authorized for pregnant women and pregnant people who are 32 to 36 weeks pregnant to protect infants from RSV.
  • mRNA-1345 (mRESVIA^®, Moderna) was authorized on November 6, 2024, to protect adults 60 years of age and older.

Following a thorough review of the evidence, NACI makes the following recommendations for public health program decision-making (i.e., provinces/territories making decisions for publicly funded immunization programs):

• NACI continues to strongly recommend RSV immunization programs for adults 75 years of age and older, particularly for older adults who are at increased risk of severe RSV disease.
  • One dose of either RSVpreF, RSVPreF3 or mRNA-1345 can be used. While all vaccines work well, there is less information available for mRNA-1345 than for RSVpreF or RSVPreF3.
• NACI continues to strongly recommend RSV immunization programs for adults 60 years of age and older who are residents of nursing homes and other chronic care facilities.
  • People living in nursing homes and other chronic care facilities are more likely to have severe RSV outcomes than those with other living situations.

For individuals who may seek vaccination outside of a public health program, NACI makes the following recommendation for individual level decision-making (i.e., healthcare providers advising individual clients):

• NACI recommends that an RSV vaccine may be considered as an individual decision by adults 50 to 74 years of age in consultation with their health care provider.
  • For adults 60 to 74 years of age, RSVpreF, RSVPreF3, or mRNA-1345 can be used as a single dose schedule.
  • Only RSVPreF3 is authorized for use in adults 50 to 59 years of age, administered as a single dose schedule.
  • NACI has identified clinically significant chronic health conditions that place individuals at increased risk of severe RSV disease. Vaccination against RSV is more beneficial for these individuals. See the full NACI statement for more details.

NACI will continue to review emerging evidence and update guidance as needed.

To receive a PDF copy of the full NACI statement, please email naci.publications-ccni@phac-aspc.gc.ca. A fully accessible version of the statement will be available online on the NACI web page and updates to the RSV chapter will be published in the Canadian Immunization Guide (CIG) as soon as possible.

What you need to know

• Respiratory syncytial virus (RSV) is a common respiratory virus that can have serious complications for older adults and adults with certain medical conditions, including hospitalization, intensive care unit admission, and death.
• RSV vaccines work best when given just before or during the RSV season, which is typically November to April in Canada.
• In this latest update, NACI has provided advice that expands the ages where the GSK vaccine RSVPreF3 may be used, in line with clinical trial evidence and the recent Health Canada changes to age groups in the product label.
• NACI is also now recommending that a new RSV vaccine from Moderna (mRNA-1345) may be considered as one of the vaccine options for provincial and territorial RSV vaccine programs and for older adults at increased risk of disease.
• While the GSK RSVPreF3 RSV vaccine may now be used in adults aged 50 and older, the other RSV vaccines may be used in adults aged 60 and older.
• NACI continues to strongly recommend vaccine programs for adults 75 years and older, or adults 60 years of age and older who are residents of nursing homes and other chronic care facilities.
• RSV vaccines can be given at the same time as, or at any time before or after, other adult vaccines. If possible, RSV vaccines should be given at least six weeks before or after non-seasonal vaccines, for example, shingles or diphtheria-tetanus vaccines. This is to avoid inadvertently attributing an adverse event from another vaccine to the RSV vaccine or vice versa.
• Preliminary data suggests that RSVpreF and RSVPreF3 might increase the risk of Guillain-Barré Syndrome (GBS). Additional studies are anticipated in the short term.
• Although there is still uncertainty about how long protection against RSV will last, available evidence demonstrates that a single dose of RSV vaccine provides protection from RSV disease for at least two years. It is not yet known if the responses for these vaccines can be boosted with further doses. As a result, healthy adults may wish to defer vaccination until a time when they are at greater risk.
• Provinces and territories determine their vaccination programs and policies, including those for RSV, based on their unique circumstances, including local epidemiology. Individuals are encouraged to consult a trusted health care provider to see which options are available.
• NACI will continue to monitor the evolving evidence and will update guidance as needed and as new products or indications for RSV vaccines are authorized by Health Canada.

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