This text is taken from our newsletter “Coronavirus Mail” of May 2, 2022. To subscribe, click here.
Fatigue, headaches, breathing difficulties: some people feel the effects of COVID-19 months after the acute phase of their infection. Do vaccines protect against these ailments? Interview with Dr. Emilia Liana Falcone, who directs the Post-COVID-19 Research Clinic at the Montreal Clinical Research Institute (IRCM).
What do large epidemiological studies say about the protective effect of long-lasting COVID vaccines?
Most of the studies on this have yet to be peer-reviewed, but there’s definitely the notion that there may be a protective effect, says Dr. Falcone. According to some studies, vaccination would reduce the risk of developing long-term COVID by around 50%.
From a biological point of view, what can we deduce about the protective mechanism?
Part of the protection is explained by the fact that vaccination reduces the risk of having a serious infection. We know that there is a link between a very serious disease and the risk of developing long-term sequelae.
One of the hypotheses to explain long COVID is that inflammation occurring during the acute phase causes long-term sequelae. If the infection is a little more controlled [grâce au vaccin], it would not cause such significant dysregulation of the immune system. That said, these issues are being actively explored.
Do we know if the situation is the same with the Omicron and BA.2 variants?
We don’t have the answer yet. What I can tell you is that, certainly, we have cases of long COVID that arrive after Omicron infections. For BA.2, it’s still too early to tell. Will the post-COVID-19 syndrome be as severe, and will the proportion of long COVID be as large? That remains to be determined.
My hope — and my inference, given the protective effect of vaccination — is that the proportion of infected people who develop long-lasting COVID will decrease. However, since these variants are more contagious, the absolute number of people affected is still likely to be high.
If COVID-19 becomes endemic, what do you think will happen to long-lasting COVID?
I feel like there always will be. Because we know that long COVID can occur even if the disease is less serious. The difference is that we may be able to identify it better, characterize it better, take care of it better: we will know more what to expect.
In addition, several ongoing studies are looking at the impact of interventions during the acute phase, to see if they alter the risks of long-term COVID. It will be really interesting to see, by the time more people have received Paxlovid in the acute phase of their disease, if this will reduce the risk of having long-lasting COVID. It is an important issue.