Earlier this month, the National Advisory Committee on Immunization (NACI) said that people facing high risk of severe illness should get another COVID-19 booster in the spring.
With the latest messages targeting specific groups and COVID-19 cases seemingly stable across the country, many Canadians may be wondering if or when they should schedule their next booster shot.
Here is a summary of NACI’s current COVID-19 vaccination guidelines, both for children and adults who are at increased risk of severe illness and those who are not.
PRIMARY VACCINE SERIES
Other than a very small number of people with legitimate medical exemptions, NACI says that all Canadians five years of age and older should be vaccinated against COVID-19 with a full series of primary vaccinations. The number of doses considered to form a complete series depends on the vaccine and the person vaccinated.
For people of most ages receiving the Pfizer-BioNTech Comirnaty or Moderna Spikevax vaccine, and who do not have moderate or severe immunosuppression, a complete series consists of two doses eight weeks apart.
For children between the ages of six months and four years who receive the three microgram pediatric formulation of the Pfizer-BioNTech Comirnaty vaccine, a complete series consists of three doses, eight weeks apart.
For children six months and older receiving the original Moderna Spikevax vaccine, the full series still consists of two doses, eight weeks apart.
NACI’s guidance for children six months to less than five years of age is that they “may be immunized with a primary series of a licensed mRNA vaccine,” which the organization calls a “discretionary recommendation.”
For adults 18 years and older receiving the Janssen Jcovden vaccine, a complete series is one dose.
What constitutes a full primary vaccine series for moderately to severely immunocompromised people looks a bit different, with the NACI recommending more doses and shorter dosing intervals of between four and eight weeks.
Children receiving the three microgram pediatric formulation of the Pfizer-BioNTech Comirnaty vaccine should receive four doses.
For all other immunocompromised individuals receiving the original Pfizer-BioNTech Comirnaty vaccine or the original Moderna Spikevax vaccine, a full course is three doses.
A full course of the Novavax Nuvaxovid vaccine or the Medicago Covifenz vaccine is two to three doses. A full course of the AstraZeneca Vaxzevria vaccine consists of two doses, plus one dose of an mRNA vaccine, and a full course of the Janssen Jcovden vaccine is one dose, plus one dose of an mRNA vaccine.
BOOSTER DOSE
Because vaccine protection wanes over time, and because the COVID-19 Omicron variant and its subvariants continue to circulate in Canada and around the world, NACI and Health Canada recommend booster dose six months after the last dose of a primary course for all persons five years and older.
“It remains important to stay up-to-date with your COVID-19 vaccinations, including recommended booster doses, given the continued circulation of SARS-CoV-2 virus variants in Canada and elsewhere,” said Dr. Theresa Tam, Director of public health of Canada, said in a press release on March 3. “Booster doses help rebuild protection against severe disease that wanes over time after vaccination or COVID-19 infections.”
Specifically, NACI and Health Canada recommend bivalent COVID-19 mRNA vaccines containing Omicron as the “preferred booster” for fully vaccinated persons five years of age and older.
according to the current canadian vaccination guide regardless of previous booster doses, adults 65 years and older who have received all immunizations should have received a booster dose since early fall.
The same recommendation applies to adolescents and adults between the ages of 12 and 64 who are at increased risk of severe illness from COVID-19, including those who are immunocompromised.
All fully vaccinated adults between the ages of 18 and 64 who are not at increased risk of severe disease should have received at least one booster dose since their primary series, as long as six months have passed since their last primary dose. If someone received a booster dose before the beginning of fall 2022 and it has been at least six months since their last dose, they are now eligible for another booster dose.
Children between the ages of five and 11 with an underlying medical condition that places them at high risk of severe illness from COVID-19 should also receive support, NACI says.
There are no authorized COVID-19 vaccine boosters for children under five years of age.