Will COVID booster shots be available in Canada this year? Experts say yes, but not for everyone.

Janet Lang has had two doses of coronavirus vaccine, but she still wears a mask every time she leaves the house. Lang, 73, is undergoing oral chemotherapy to treat a rare blood malignancy. Although the medications have helped to hold cancer at bay, they have also suppressed her immune system, leaving her with the continual concern that even if she is fully inoculated, it is insufficient to protect her against COVID-19.

"I'm feeling rather frail," Lang said in an interview near her home in Waterloo, Ont. A booster dose, she suggested, would help calm her anxieties, especially about the delta variety.

With the rise of the more transmissible delta variant, a lack of clarity about when boosters might be required, and calls from the World Health Organization to get the world vaccinated before rich countries worry about third doses, booster shots will be one of the next big decisions for Canadian officials.

Booster shots are typically used to boost the body's antibody response to a virus after the immune system has been "primed" by the original immunization (for example, tetanus shots). Additional vaccine doses can also assist the body in fighting off different virus types (like the yearly flu shot).

Vaccine producers, such as Pfizer and Moderna, are developing and testing booster injections against Sars-CoV-2, the virus that causes COVID-19, and potential new variations. According to Canadian specialists, the current COVID-19 vaccine schedule provides great protection, including against the delta form. However, it is not yet clear how long that protection lasts in different populations and thus when or if a booster shot will be required.

Lang may yet achieve her dream in the coming months if Canada follows the lead of the United Kingdom's Joint Committee on Vaccination and Immunisation (JCVI), which has already issued recommendations on potentially commencing a booster shot campaign in around two months.

The British committee suggests that those who are immunocompromised, living in long-term care or retirement homes, persons aged 70 and older, and front-line health workers be the first to receive the third dose of COVID vaccination, also known as a booster shot.

The targeted approach to booster doses used in the United Kingdom is "perfect," according to Dr. Allison McGeer, an infectious disease expert at Mount Sinai Hospital in Toronto.

Dr. André Veillette, an immunologist at the Montreal Clinical Research Institute and a member of Canada's COVID-19 vaccine task force, believes that while vaccines are currently doing an excellent job of controlling COVID-19 in Canada, it would be prudent to offer booster shots to vulnerable populations in the fall.

Both McGeer and Veillette agree that those in long-term care, the elderly, and those with impaired immune systems should receive booster doses first.