A less deadly second wave?

The number of deaths from COVID-19 right now in Quebec, as the second wave begins, has nothing to do with the death toll we experienced in the first wave. Several factors explain this difference in mortality.

On April 28, when the epidemic was raging dangerously, there were 128 deaths in Quebec, while, on September 22, there were only 3. Figures that really give the impression that the infection is less ferocious than it was not in the spring.

In the majority of countries that are in the midst of the second wave, death rates appear to be lower than in the first wave again. We see it in Italy and other countries in Europe, notes Dr.r Donald Vinh, infectious disease specialist and immunologist at the McGill University Health Center (MUHC).

But to explain this phenomenon, researchers put forward several hypotheses. “Maybe the virus is weaker. This is a hypothesis which is put forward, but which is not proven. Certainly that’s probably not the main reason, “says Dr.r Vinh.

According to a known effect in epidemiology, the first wave having mostly decimated the most vulnerable people, i.e. the elderly and people already having health problems, then remain people who are less vulnerable or not very vulnerable during the second wave, he continues.

“Maybe the virus has changed slightly and this change allows it to spread more easily among young people than among seniors. In addition, the behavior of young people of course contributes to this phenomenon. The second wave could thus target more young people because of their lack of respect for instructions. However, we know that young people are less at risk of seriously suffering from the infection. This could explain why we are seeing a decrease in mortality, ”he says.

Follow the evolution of COVID-19 in Quebec

“At the moment, as we are doing a lot more screening of asymptomatic people, such as young people who have gone to parties, we detect more people who will be not very sick, because young people are usually much less sick than older people, ”adds Dr.r Marc Dionne, public health doctor at the CHU de Québec research center.

“In addition, we treat patients better. We know better when to give them oxygen, cortisone or blood thinners, a treatment we weren’t using at the start, ”he adds.

“Today we are probably providing better care for the few patients who have had to be hospitalized in recent times,” says Dr.r Matthew Oughton, microbiologist at the Jewish General Hospital, Montreal. “Six to seven months after the onset of this pandemic, we have a better understanding of what works and what does not in terms of medication and supportive care, which is probably contributing to the decline in mortality a little. At the start of the first wave, hydroxychloroquine was thought to be beneficial based on data from France; now we know that this drug absolutely is not, we don’t waste time with it anymore. We now know that dexamethasone is very effective in reducing mortality. We also know that it is best not to intubate all patients requiring intensive care, unless there are no other options. “

“As Public Health explained, not only here in Quebec, but also elsewhere in Canada, the majority of new cases that we see occur in a younger and healthy population, generally older adults. from 20 to 40 years old. However, this group has a significantly lower risk of developing serious complications and dying than most patients in the first wave, ”he recalls.

“But the big threat to our health system will come from transmission in the community by this population of young adults, because it is very likely that we will see underlying transmissions to more vulnerable groups, such as the populations of CHSLDs and nursing homes. private residences for seniors, or even socio-economically disadvantaged people, who have been identified as at risk of complications, as we saw during the first wave, ”he believes.

“Just because you have a low risk of complications doesn’t mean you aren’t infectious. The greater the number of cases in the community, the less control we have over these transmissions, the more likely it is that transmission will continue. However, there is a lot of data indicating that we are having more and more difficulty in controlling transmission in the community today. When we see the increase in the number of cases in the community, after a certain delay there will be an increase in hospitalizations, then after another delay there will be an increase in the number of complications and deaths. It will not happen tomorrow, but in the next three to four weeks, ”says Dr.r Oughton.

“The lower mortality is explained by the fact that this second phase affects a younger population. But it is only a matter of time before the most vulnerable are reached “, summarizes the Dre Cécile Tremblay, infectious disease specialist at the CHUM.

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