New advice to wait 3 months after COVID-19 infection before booster comes amid mixed messages, lack of tests
Any vaccinated Canadian who gets infected with SARS-CoV-2 should wait three months before getting a COVID-19 booster shot, Canada's National Advisory Committee on Immunization (NACI) now recommends.
The new guidance comes as millions of Canadians have become infected in mere weeks, thanks to the fast-spreading, immune-evasive Omicron variant — and amid a patchwork of provincial recommendations and lower access to testing that can confirm whether people even had COVID-19.
In the Canada-wide recommendations, released on Friday, the NACI team said a longer interval between infection and vaccination "may result in a better immune response as this allows time for this response to mature in breadth and strength, and for circulating antibodies to decrease, thus avoiding immune interference when the vaccine is administered."
At this point, there is "insufficient clinical or real-world data" to inform guidance on the ideal interval between infection and vaccination, NACI noted, with the advisory body instead relying on available data and the basic principles of vaccinology and immunology.
For vaccinated individuals aged 12 and up who are eligible for a third dose, the recommendations suggest waiting three months after the onset of symptoms, or following a positive test for anyone who was asymptomatic — while also being at least six months out from a second dose.
Those who experienced SARS-CoV-2 infection before starting or completing their primary COVID-19 vaccine series may receive their next dose eight weeks after symptoms started or after testing positive, according to the guidelines.