Omicron begins to reveal its secrets. The fifth “variant of concern” identified so far by the World Health Organization (WHO) monopolizes the efforts of a multitude of scientists, and certain trends emerge from their research. State of play with experts, whose comments were collected by Jean-Louis Bordeleau.
How fast does Omicron spread?
A lot of uncertainties hover around Omicron, but one thing is certain: this variant is spreading very quickly. Its transmission rate (Rt) is 4.01 according to Ontario health authorities, while the UK estimates it at 3.7. In other words, each individual infected with Omicron will in turn infect between three and four other people. This rate of spread is equivalent to that observed at the very beginning of the pandemic.
These data are “credible”, confirms virologist Benoit Barbeau. Omicron “is transmitted extremely actively, even in a population that is relatively well vaccinated”.
People who have already contracted COVID-19 are also at greater risk of falling ill a second time. “We are talking about twice the chances of reinfection with Omicron compared with the Wuhan strain”, notes the DD Judith Fafard, medical director of the Laboratoire de santé publique du Québec.
We talk about twice the chances of reinfection with Omicron compared with the Wuhan strain
Omicron has been detected in 77 countries so far, according to the WHO.
Do vaccines protect against this variant?
Omicron reduces the effectiveness of vaccines “significantly”, according to the bosses of Pfizer-BioNTech and Moderna.
The double dose of Pfizer-BioNTech’s vaccine prevents 70% of hospitalizations linked to Omicron, according to a South African study presented on Tuesday. The vaccine was previously 93% effective against severe cases. Moderna’s data has yet to be made public.
A third dose “neutralizes” the Omicron variant, recently specified the boss of BioNTech, Uğur Şahin. This booster dose achieves a level of protection of 95% efficacy “against any level of severity of the disease”.
In Quebec, this third dose is only recommended for people who are immunocompromised, those aged 60 and over, residents of CHSLDs, people who have received two doses of AstraZeneca, pregnant women, and those suffering from a chronic disease. as well as health workers in contact with users.
Omicron also reduces the ability of vaccines to prevent infections, according to preliminary laboratory data. “For some patients, the neutralization potential of vaccines is 23 times less effective for Omicron”, observes DD Judith Fafard.
Does Omicron cause more severe symptoms?
Many scientists are looking at the question. Symptoms appear “mild to moderate and less severe than Delta” in both southern Africa and Europe, according to the WHO.
“It’s quite risky to transpose that here”, nuance Alain Lamarre, specialist in immunology and virology for the National Institute of Scientific Research. The populations studied are younger, less vaccinated and were more infected in the past than in Quebec. “At the moment, I don’t think Omicron looks more virulent. But from there to saying that it is less, we will have to wait a little longer for other studies to come out. “
Reliable data from Britain is expected to be released “within days”.
How can we protect ourselves otherwise?
As with the other variants, wearing “good masks”, teleworking and rapid tests make it possible to “control” the pandemic, underlines Benoit Barbeau. “There are also interventions to be done in terms of ventilation, air purification. “
In addition, health professionals have an arsenal of treatments to fight against COVID-19. Pfizer confirmed on Tuesday that its anti-COVID pill reduced hospitalizations and deaths among those at risk by nearly 90%.
However, the epidemic surge seems inevitable, according to Alain Lamarre. “Is that going to completely avoid a wave?” I do not think so. We see that the cases are increasing, and it is probably still only Delta, or in majority. We will not escape it. “
How worried should we be about this variant?
Omicron is coming “at the wrong time”, specialists agree. The holiday season and its share of encounters are conducive to contagion. “This is the time to keep our measures and to make the population a little aware by telling ourselves that it is not because we have the right that we are obliged to make a decision. party 20 people, ”advises Mr. Lamarre.
“Even if Omicron is not more severe, because of an explosion of cases, it risks giving more hospitalizations and putting further stress on the health system, warns the DD Judith Fafard. From the point of view of individual risk, it is not the end of the world, but it is the accumulation of all these cases that worries. “
The actual impact of Omicron will therefore depend on the hospitalization rate and the size of the number of infections.