Summary of NACI statement of October 27, 2023: Updated guidance on the use of COVID-19 vaccines in individuals who have not previously been vaccinated against COVID-19

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Organization: Public Health Agency of Canada

Date published: 2023-10-27

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Updated guidance

Going forward, XBB.1.5 vaccines are the recommended products for those previously unvaccinated and previously vaccinated.

For primary series COVID-19 vaccine in those who were not previously vaccinated, NACI recommends that:

For those previously vaccinated but who did not receive an XBB.1.5 vaccine, a dose of XBB.1.5 is recommended 6 months following previous vaccination or SARS-CoV-2 infection (whichever is later). Shorter intervals (i.e., 3 months to less than 6 months) following previous vaccination or infection have also not been shown to pose a safety risk.

The NACI Statement also provides guidance for those who started a primary series with earlier (non-XBB.1.5) COVID-19 vaccines but did not complete the series.

NACI will continue to monitor the evolving evidence and will update guidance as needed.

For the full Statement, including supporting evidence and rationale, as well as comprehensive dosing schedules, please see NACI's Updated guidance on the use of COVID-19 vaccines in individuals who have not previously been vaccinated against COVID-19.

What you need to know

For more information on NACI's recommendations on the use of COVID-19 vaccines, please refer to the COVID-19 vaccine chapter in the Canadian Immunization Guide (CIG), as well as additional statements on the NACI web page.


"The COVID-19 vaccine schedule has become more complex for Canadians over time, as more vaccines and boosters have been approved. Following the authorization of the XBB.1.5 COVID-19 vaccines, NACI has worked to simplify the guidance for those who have not been previously vaccinated, including all age groups and for those with and without immunocompromising conditions. Most people 5 years of age and over need only one dose of XBB.1.5 COVID-19 vaccine this fall, regardless of whether or not they have been previously vaccinated. NACI continues to encourage Canadians to receive a dose of XBB.1.5 this fall to help protect themselves against the most prevalent strains. This is especially important for those most at risk of severe illness. NACI's recommendations are grounded in the best available scientific evidence. We will keep monitoring the situation and update our guidance accordingly."

Dr. Shelley Deeks, NACI Chair

"I want to express my gratitude to NACI for their updated guidance on COVID-19 vaccination. NACI has simplified its recommendations on providing COVID-19 vaccines to anyone 6 months or older who has not previously been vaccinated against COVID-19. One dose of the updated XBB.1.5 vaccine is recommended for most people 5 years of age and older who are previously unvaccinated. As we enter the fall and winter seasons, protection against SARS-CoV-2 and other respiratory viruses can be increased by getting vaccinated along with the use of personal protective measures."

Dr. Theresa Tam, Canada's Chief Public Health Officer

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