Unlike last year, there are no more sanitary measures in place, recalls Mr. Barbeau.
When the temperatures go down, people will be more inside, we should expect an increase in cases.
According to Marc Brisson, director of the COVID-19 Modeling Group at 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 over the coming months, including the type of variant in circulation and the maintenance of hybrid immunity, i.e. the immunity acquired by infection in a vaccinated person.
Are we protected by 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 large wave early this fall.
If the government has officially recorded less than 1,500 cases per day this summer, theINSPQ (New window) that between 3.3 million and 4.6 million Quebecers have been infected since May. About a million Quebecers were infected in August and September alone.valued
According to the report by Mr. Brisson’s team, dated 1er June (before the last summer surge), an estimated 65% of the population had hybrid immunity; 15% had natural immunity (unvaccinated, 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 reinforce one’s immunity acquired by a vaccine, but Mr. Brisson explains that it is still difficult to say with certainty for 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 hospitalizationhe recalls.
” Three months ago, hybrid immunity [observée par l’INSPQ chez des travailleurs de la santé] 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 within a short period of time are likely to be more common, Barbeau warns.
Prior to the arrival of Omicron, it was claimed that reinfection was rare before 90 days. The presence of several sub-variants means that a person can be infected several times by a different version of the virus in a short period of time.
We have seen people reinfected after four weekshe says.
In addition, many people received their 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.
If the situation seems to have stabilized for a few weeks, the number of cases and deaths remains very high compared to the same date last year, warns Mr. Barbeau. Any further upsurge could certainly have a pronounced impact, he says.
This is also what writes Patricia Hudson, scientific director of the Biological Risks Directorate at theINSPQin the report prepared with Mr. Brisson.
” Even if the new variants are less severe, the large number of cases could cause significant disruption in society and pressure on the healthcare system. »
Moreover, remember that the very high number of infections by Omicron led to a significant number of deaths. For example, from 1er August to September 15, 2022, nearly 700 Quebecers have died of COVID-19. In comparison, during this 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 the event of a loss of immunity (natural, vaccine or hybrid), an upsurge in cases and hospitalizations could occur.
If a new variant escapes hybrid immunity, the number of cases could surpass 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 throughout the world. Will one of the circulating variants become dominant? Or will we see another variant appear, as was the case with Omicron?
” What will be decisive is how different this new variant will be from BA.4 and BA.5. If these subvariants are different enough, they could lead to a fairly large new spike in infections. »
In particular, BA.4.6 is monitored. In the UK, the proportion of cases caused by this subvariant rose from 3.3% to almost 10% in one month. This same variant currently accounts for 10% of cases in the United States. In Quebec, it represents nearly 20% of new cases.
Early data shows 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 further showed that monoclonal antibody treatments appear to be less effective against BA.4.6.
Also, this week theWHO (New window) recommended no longer using two other monoclonal antibody treatments – sotrovimab and casirivimab/imdevimab – since they are no longer considered effective against the different Omicron subvariants.
Another Omicron sub-variant, the BA.2.75 (New window), is responsible for increases in infections, particularly in India, and has been detected in around 20 countries. While it has not yet spread significantly across the world, scientists are monitoring it, as it is more transmissible than BA.5 and appears to cause more reinfections.
Preparing for a strong influenza season
Each year, countries in the northern hemisphere observe the influenza 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 experienced (New window) its strongest influenza season in the past five years. The season also started earlier. It is mainly young children who have been infected. On the other hand, severe complications were observed more in the elderly. The country reports 295 influenza-related deaths and the median age of those who died was 82.
It is for this reason that the Quebec government has chosen to bring forward its influenza vaccination campaign. Seniors 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 recalls that it is possible to be infected successively by the flu and COVID-19 and that it is possible for a person to be infected at the same time by COVID-19 and by influenza. A vaccine against COVID-19 does not protect against influenza.
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 tell the two viruses apart with certainty, and self-testing remains an important tool, he says.
A study published this week in 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 almost 80%. This is what the Government of Quebec has been recommending for several months.
He recommends that people who haven’t had a dose of the COVID-19 vaccine in more than five months go get a new dose.
Mr. Barbeau reminds that anyone who has symptoms resembling the flu or COVID-19 should take precautions such as wearing a mask in public and staying at home.
It is not a question of being alarmist, but of having a conscience. We must take action to avoid being a source of transmission. The virus [de la COVID-19] is less active at the moment, but we don’t want to give it a boost that could lead us to another wave more difficult than the previous ones.
Finally, Mr. Barbeau believes that we should talk more about adapting to the virus than about
living with the virus.
The virus continues to adapt and we have to too, depending on what the virus gives ushe says, adding that one day the virus should become more stable, as it does with the flu.