Booster shots are being provided to a variety of vulnerable groups starting this week.

Those eligible for a booster shot include adults in seniors homes and other congregate living facilities, adults 70 years and older, people who have only received two doses of the AstraZeneca vaccine, those who have only received one dose of the Janssen vaccine, Indigenous residents or those who live in an Indigenous community, and frontline healthcare workers who have direct in-person contact with patients.

Those looking for a booster shot will need to wait 6 months since their previous COVID vaccines.

Memorial University researcher and Professor of Immunology, Dr. Michael Grant says the most vulnerable are those in long-term care.

The older a person is, the weaker the initial response is to the vaccine, and the faster the response might wane says Grant.

The need for a booster is different for those who have an autoimmune disease or who are a cancer survivor.

In those cases says Grant, the person may not have responded very well, or at all to the original vaccination regimen. That means a third shot is required to push their immune response to that that will provide adequate protection.