We know that immunity – whether infection-acquired, vaccine-induced, or hybrid in nature – wanes within several months. What schedule should I keep in order to maximize my immunity and ensure that I am up to date with my vaccinations?
The simple answer about what to do is: follow public health recommendations and make sure you stay up to date with vaccination.
At the moment, that means you should have had:
- four doses of a COVID-19 vaccine if you are over 60 years of age;
- three doses if you are between 18 and 59;
- two doses if you under 18; and
- five doses if you are severely immunocompromised.
Even if you are up-to-date, protection against milder infections wanes over several months, and protection against severe infection may start to wane – at least to some degree – after six to nine months. Thus, it is very likely that in the fall, public health experts will recommend that, at least, older adults, and perhaps everyone, should get another dose of vaccine.
This waning is also why experts are recommending that adults under 60 should consider a fourth dose now, if they have good reason to want to avoid infection or the risk of transmission of disease to others. Four doses (or five in the fall) may seem like a lot. It is certainly more that is usually needed to protect you from infectious diseases. However, we are living through a pandemic – these are not ordinary times, and the best solutions are not ordinary either.
Having said this, recommendations for the fall have not yet been made because the pandemic is still evolving. Public health officials won’t recommend added doses unless they are certain that they are needed. Antibody levels persist for longer after three or four doses than after two, and the combination of vaccine and infection (hybrid immunity, which is the situation for at least 40% of Canada’s population) is considerably more protective than infection or vaccine alone. Thus, additional doses may not be needed for everyone.
On the other hand, new variants may be coming which more effectively evade the immune system, making added doses necessary. Most people would like the added doses to include spike proteins from new variants, but to date vaccines containing Omicron-specific antibodies actually don’t look much better than the original vaccines. As with so much about the pandemic, the virus and our understanding of immunity continues to evolve, and we need to wait to be sure what the best course of action will be in the fall.