The National Advisory Committee on Immunization (NACI) released its updated guidelines on Friday on the use of COVID-19 vaccines during the upcoming fall season.
Although COVID-19 rates are currently low across the country, NACI said it anticipates a surge in activity during the fall and winter months, aligning with patterns seen in previous years and consistent with the behaviour of other respiratory viruses.
“As COVID-19 activity is expected during the upcoming fall and winter months, and COVID-19 disease can compound the impact on the health system of other fall and winter respiratory viruses, NACI continues to provide early guidance on the use of COVID-19 vaccines to facilitate planning by provinces and territories,” the guidelines state.
“An updated vaccine to replace the current XBB.1.5 vaccine may be available starting in the fall of 2024, depending on the epidemiology of SARS-CoV-2 and recommendations of international advisory groups expected in mid-spring 2024.”
Starting in the fall of 2024, NACI strongly recommends the most recent updated COVID-19 vaccines for previously vaccinated and unvaccinated individuals at increased risk of SARS-CoV-2 infection or severe COVID-19 disease as follows:
- All adults 65 years of age or older.
- Those six months of age and older who are:
- residents of long-term care homes and other congregate living
settings - individuals with underlying medical conditions that place them at
higher risk of severe COVID-19, including children with complex
health needs - individuals who are pregnant
- individuals in or from First Nations, Métis and Inuit communities
- members of racialized and other equity-deserving communities
- people who provide essential community services
- residents of long-term care homes and other congregate living
All other previously vaccinated and unvaccinated individuals (six months of age and older) who are not at increased risk for SARS-CoV-2 infection or severe COVID-19 may receive the most recently updated vaccine in the fall of 2024.
And for unvaccinated people aged five years of age and older who are moderately to severely immunocompromised, NACI recommends that two doses should be given and an additional dose (for a total of three doses) may be given, regardless of vaccine platform.
For previously vaccinated individuals, NACI recommends an interval of six months from the last dose, with a minimum interval of three months from the last dose. This minimum will ensure that those who receive a spring 2024 dose (which includes those who are most at risk for severe disease) will be eligible again for an updated fall 2024 dose when it becomes available, NACI said.
Omicron sublineages of COVID-19 continue to circulate in Canada and globally, NACI said. From sequencing data up to the week of March 10, JN.1 sublineages, are the most prevalent among all positive cases sampled across Canada.
“There is not yet sufficient data to determine the best time to start the COVID-19 vaccination program in the fall, although preliminary observations from previous seasons suggest that COVID-19 activity began to increase before fall vaccination campaigns were rolled out,” NACI said Friday. “In 2023, the national percent positivity of COVID-19 testing began to increase in mid-August.”
In August 2023, after months of low transmission of the virus, COVID-19 started to rise across the country due to two variants on the scene, EG.5, a subvariant of Omicron, and BA.2.86.
Although COVID-19 cases started to spike, the rollout of the fall 2023 boosters did not happen until around October.