Unlike last year, there are no more sanitary measures in place, Barbeau recalls. As temperatures drop, people will be more indoors, we should expect an increase in cases.
According to Marc Brisson, director of the COVID-19 Modeling Group at the Université Laval and the Institut national de santé publique du Québec (INSPQ), who recently published hypothetical scenarios (New window) evolution of the epidemic, several factors will determine the extent to which COVID-19 will have an impact in the coming months, including the type of variant in circulation and the maintenance of hybrid immunity, that is, immunity acquired by infection in a person vaccinated.
Are we protected from this latest wave?
Mr. Barbeau believes that the fact that so many people have been infected and vaccinated in recent months reduces the risk of a new big wave early this fall.
If the government officially registered fewer than 1,500 cases a day this summer, theINSPQ appreciated (New window) that between 3.3 million and 4.6 million Quebecs have been infected since May. About one million Quebecers were infected in August and September alone.
According to Mr. Brisson’s team report, dated 1is June (before the last summer wave), it is estimated that 65% of the population had hybrid immunity; 15% had natural immunity (unvaccinated and infected population); and 15% had vaccine immunity (vaccinated, uninfected population). Less than 5% of the population has never been vaccinated or infected.
An infection makes it possible to strengthen their acquired immunity from a vaccine, but Mr. Brisson explains that it is still difficult to say for sure how long these people are really protected by this hybrid immunity.especially against infection and the risk of hospitalization “,” text “:” This protection decreases over time, especially against infection and the risk of hospitalization “}}”>This protection decreases over time, especially in the face of infection and the risk of hospitalizationremember.
” Three months ago, hybrid immunity [observée par l’INSPQ chez des travailleurs de la santé] it was very strong. Have we had a gradual decline since then? This element needs to be monitored. “
As people’s immunity wanes, cases of reinfection over a short period of time are likely to be more common, Barbeau warns.
Before Omicron’s arrival, reinfection was claimed to be rare before 90 days. The presence of different sub-variants means that a person can be infected multiple times with a different version of the virus in a short period of time. We have seen people reinfected after four weeks
he says.
Furthermore, many people received the last dose of the vaccine more than five months ago, which could have an impact on the evolution of the pandemic. Only 23% of Quebecers currently have up-to-date COVID vaccination coverage, according to the Ministry of Health and Social Services.
In Quebec, you can get one free box of self-tests per month at a pharmacy.
Photo: The Canadian Press / Jeff McIntosh
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If the situation appears to have stabilized for a few weeks, the number of cases and deaths remains very high compared to the same date last year, warns Barbeau. Any further increases could certainly have a pronounced impact, she says.
This is also what Patricia Hudson, scientific director of the Biological Risks Directorate at theINSPQin the report prepared with Mr. Brisson.
” Although the new variants are less severe, the high number of cases could cause significant societal disruption and pressures on the health system. “
We also remember that the very high number of infections by Omicron has led to a significant number of deaths. For example, from 1is From August to September 15, 2022, nearly 700 Quebecers died of COVID-19. By comparison, during the same period, there were 84 deaths in 2020 and 49 in 2021.
In the scenarios studied by M. Brisson, if hybrid immunity is maintained, the impact of a new wave caused by a variant similar to BA.4 and BA.5 could be limited.
In case of loss of immunity (natural, vaccine or hybrid), there could be an increase in cases and hospitalizations.
If a new variant escapes hybrid immunity, the number of cases could exceed that of the Omicron wave and lead to a significant number of hospitalizations.
Variants to watch out for
For now it is still difficult to say with certainty which variant will take the place of the BA.4 and BA.5 which currently dominate the world over. Will one of the circulating variants become dominant? Or will we see another variant appear, as happened with Omicron?
” What will be decisive is how different this new variant will be from BA.4 and BA.5. If these subvariants are sufficiently different, they could lead to a new infection spike that is large enough. “
In particular, BA.4.6 is monitored. In the UK, the percentage of cases caused by this sub-variant has risen from 3.3% to nearly 10% in one month. This same variant currently accounts for 10% of cases in the United States. In Quebec it accounts for nearly 20% of new cases.
Early data show that BA.4.6 is no more severe than BA.4 or BA.5, but is still more transmissible and more adept at evading immune protection.
A preliminary study (New window) which has not yet been peer-reviewed, has also shown that monoclonal antibody treatments appear to be less effective against BA.4.6.
Also, this week theWHO (New window) recommended no longer to use two other monoclonal antibody treatments – sotrovimab and casirivimab / imdevimab – as they are no longer considered effective against the different Omicron sub-variants.
Another sub-variant of Omicron, the BA.2.75 (New window), is responsible for the increase in infections, particularly in India, and has been detected in about 20 countries. Although it has not yet spread significantly around the world, scientists are monitoring it, as it is more transmissible than BA.5 and appears to cause more reinfections.
Prepare for a strong flu season
Each year, countries in the Northern Hemisphere observe flu season in the Southern Hemisphere to get a better idea of what lies ahead and to match vaccines to circulating strains.
This year, Australia has experimented (New window) the strongest flu season of the past five years. The season also started earlier. It is mainly young children who have been infected. On the other hand, serious complications were observed more in the elderly. The country reports 295 flu-related deaths, and the average age of those who died was 82.
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Number of influenza cases in Australia. The red line represents the year 2022.
Photo: Australian Department of Health
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It is for this reason that the Quebec government has chosen to carry out its flu vaccination campaign. Elderly and vulnerable people are strongly recommended to receive a vaccine. It is possible to get a COVID-19 vaccine at the same time as the flu shot.
Mr. Barbeau points out that it is possible to later be infected with the flu and COVID-19, and that it is possible for a person to be infected with COVID-19 and the flu at the same time. A COVID-19 vaccine does not protect against the flu.
Can the two viruses be distinguished?
Yes, both viruses cause similar symptoms, Barbeau says, but it’s still important to test for COVID-19. This is the only way to distinguish the two viruses with certainty, and self-testing remains an important tool, she says.
A study published this week on the British medical journal (New window) shows that the efficiency of self-tests for COVID-19 decreases from about 80% to about 70% for the Omicron variant. However, people who take a sample not only from the nose, but also from the throat and cheeks, see the effectiveness of the self-test return to nearly 80%. This is what the Quebec government has been recommending for several months.
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To increase the chances of detecting the virus, it is recommended to rub the inside of each cheek for at least 5 seconds before taking the sample from both nostrils.
Photo: AFP / PATRICK T. FALLON
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It recommends people who have not received a dose of the COVID-19 vaccine for more than five months to take a new dose.
Mr. Barbeau points out that anyone with flu or COVID-19-like symptoms should take precautions such as wearing a mask in public and staying at home.
It is not a question of being alarmists, but of having a conscience. We must act to avoid being a source of transmission. The virus [de la COVID-19] he is less active at the moment, but we don’t want to give him a push that could lead us to another wave that is more difficult than the previous ones.
Finally, Mr. Barbeau believes that we should talk more about adaptation to the virus than about live with the virus
.
The virus continues to adapt and so must we, depending on what the virus offers us
he says, adding that someday the virus should become more stable, as it does with the flu.
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