Mass contamination: call for caution in major events

Mass contamination: caution in major events


While the Festival d'été de Québec is in full swing and big events are happening, COVID is playing spoilsport. Infections are on the rise and sanitary measures are minimal or even completely absent in some cases. How to protect yourself to limit the spread without sulking your pleasure? The Journal put the question to Kevin L'Espérance, epidemiologist.

Q: Sanitary measures are rather rare in events this summer. How to protect yourself?

A: Covid-19 is transmitted mainly by aerosol. My main recommendation is, if possible, to wear the mask. This is the best measure we have at our disposal to protect ourselves individually and collectively. This drastically reduces transmission and infection in crowds. It is also necessary to encourage external events and have an up-to-date vaccination.

Q: Is it premature to hold major events without sanitary measures?

A: From an epidemiological point of view, it certainly worries me. But the social isolation that comes with overly restrictive health measures is not good for our psychological and physical health either. You have to try to balance things out, but I think that during major mass events, like the Festival d'été de Québec, we should stay as much as possible with the group we arrived with, encourage distancing and wear the mask as much as possible, especially for indoor and poorly ventilated events. Outside, the risk of transmission remains relatively low, but not zero.

Q: Could mass contamination, such as that observed this summer, be beneficial for the herd immunity, in a context where the population is mainly vaccinated?

A: The strategy of relying on natural immunity can be dangerous. Hypothetically speaking, if we are in a context where there are zero sanitary measures and we tell everyone to go and catch COVID, there is a risk of infection booms, as at the moment, and we will suffer the repercussions, such as deaths and severe forms. There are still many uncertainties about the virus and the medium and long-term repercussions. On the other hand, contracting COVID-19 confers some immunity. But natural immunity is difficult to study. Not many things are known, such as how long it lasts and how strong it is. However, we know that it is more variable than so-called artificial immunity [vaccine].

Q: So, despite the high rate of vaccination, natural immunity is not a weapon. to adequately protect the population?

A: The effectiveness of the vaccination has been diminished over time, so it is important to have the updated doses. We can have the impression that vaccines are ineffective, because we have a lot of cases and we see an increase in severe forms of the disease. It is normal to observe this. In absolute numbers, it is directly linked to transmission, so the more transmission increases, despite the vaccine [the more we observe] an increase in severe cases. Without sanitary measures to reduce transmission, we see these increases occur.

Q: Can we hope that these mass contaminations will avoid another wave in the fall?

A: It's very hard to say. The last two summers, the contamination was less, because we were more outside and there were still measures in place. There are almost no measurements here. We did not expect such a wave this summer, but it is probably because there are no favorable conditions to decrease transmission. I have the impression that in the fall, we will have to be careful [back to school and return from vacation]. If there are no measurements, I think the peak will continue beyond the summer.