"More contagious than Delta", Omicron threatens Europe

"More contagious than Delta", Omicron threatens Europe

For lack of hindsight, it is difficult to establish the virulence of the omicron variant for the moment.But in all cases, it represents a certain threat to its very strong contagiousness (from 30 to 50% more transmissible than the Delta variant), explains Gérard Schockmel, doctor consultant in infectious diseases at Robert Schuman hospitals (HRS).Its numerous mutations decrease the protection conferred by vaccination, even if a third dose makes it possible to enhance protection again, whether against infections or serious forms.

The COVVI-19 will not in any case disappear, and other variants will appear.But the vaccination and successive waves of infections make it possible to eventually hope for immune protection of the population, reducing the risks of serious forms.

With the hindsight that we now have, what do we know about the omicron variant?

Gérard Schockmel.- "What we can say with certainty is that the omicron variant is more contagious.It is 30 to 50% more transmissible than the Delta variant, who was already the champion in the matter.Thus, in South Africa, the United Kingdom or Denmark, the number of cases doubles every two to three days.

The current problem remains the Delta variant.But we will see with what speed omicron will replace Delta.In Europe, the omicron variant should become dominant in a few weeks - even if it remains an extrapolation.

But is this omicron varying more likely to cause serious forms?

"Complications take some time to develop, so we do not have enough perspective - only three weeks in South Africa.In addition, in this country, the population is young and benefits from a certain immunity, because many among them have already been infected or vaccinated.So it can give the impression that the virus is less virulent.

But, in absolute terms, it is more complicated, because it would be necessary to compare groups of infected non -vaccinated people, in one case, by Delta, and, in the other, by omicron.However, we no longer have such cases, because many people within a community are now immune to vaccination or infection.

Il y aura un plus grand nombre de cas, et par conséquent un plus grand nombre de personnes avec des complications.

Gérard Schockmel,&nbspHRS

But the current trend seems to lean towards a less strong virulence of the omicron variant ...

"If we assume that the omicron variant is less virulent, it remains very transmitted.There will therefore be a greater number of cases, and therefore a greater number of people with complications.The question is who will be concerned.

The most vulnerable people are those not vaccinated.Many non -vaccinated people will have complications, even if the variant is less virulent.So they have an interest in being vaccinated.There is also the group of people who have been infected with COVVID.At home too, antibodies fade over time, and for them too, the recommendation is to be vaccinated.

«Plus contagieux que Delta»», Omicron menace l’Europe

What about vaccinated people?The many mutations in the omicron variant seem to affect the effectiveness of vaccines ...

"For people vaccinated with two doses, immunity is indeed lower against Omicron.In the United Kingdom, current figures indicate a protection of 40% against infections a few months after the second dose and 70% against serious forms.

But the good news is that with a third dose, protection against infections dates back 80%.And everything suggests that protection also increases against serious forms-even if it remains difficult to measure-and that it lasts longer.

Avec une 3e dose, la protection contre les infections remonte à 80%. Et tout porte à croire que la protection augmente également contre les formes graves.

Gérard Schockmel,&nbspHRS

Protection against serious forms remains important.What is the reason?

"There are two lines of defense: the first, which is called humoral immunity, is conferred by antibodies and is effective against infections.This immunity fades quickly over time.

Then, a second line of defense: cellular immunity, which is effective against serious forms.It works mainly with T lymphocytes, which are part of the "killer cells".Once an infected person is infected, antibodies are no longer so effective, because it is the killer cells that will destroy infected cells.However, this immunity does not fade as quickly.

Thus, at present, a person who has received two vaccine doses benefits from 40% infection protection by antibodies, but it remains 70% protected against serious complications through cellular immunity.

Les première et deuxième doses étaient très rapprochées – trop rapprochées pour créer une mémoire immunologique à long terme. Mais l’objectif était alors de procurer une immunité maximale sur un temps court.

Gérard Schockmel,&nbspHRS

In addition, the omicron variant is characterized by many mutations.But these changes mainly concern antibodies attachment sites.However, the killer cells do not necessarily attach in the same place, so they are less affected by these mutations.

The government recently lowered the period to access the third dose of six to five months after vaccination.And this one should spend four months at the start of the year.What delay offers maximum efficiency in the third dose?

"More time between the first two doses would have conferred better immunity and better immunological memory.At the start of the vaccination campaign, the first and second doses were very close - too close to create a long -term immunological memory.But the objective was then to provide maximum immunity over a short time because, when infections are soaring, there is an emergency.

Regarding the timing of the third dose, the European Medicines Agency (EMA) has already discussed three months.I would recommend flexibility.But it is important not to lose sight of the most vulnerable people, who must remain a priority.

Le virus ne va pas disparaître.But we are going to get out of it collectively, because immunity is created from wave in wave.

Gérard Schockmel,&nbspHRS

Are the side effects of the third dose not stronger?

"It's variable.People reacted more strongly in the third dose.Others have tolerated it better than the first and second doses.There is no uniform rule.

Will a fourth dose be necessary?And, if so, what maturity?

"For the moment, we don't know.Cellular immunity has a large longevity in general.But what will be its effectiveness in the face of new variants?In all probability, the fourth dose will be done with already suitable and tailor -made vaccines for new variants.But these new vaccines will not be available for a few months.It will therefore not be necessary to wait for the third dose.

The appearance of this new omicron varying seems to worsen a situation which was already very precarious.Other variants will appear.Is an exit from the crisis possible?

"The virus is not going to disappear.But we are going to get out of it collectively, because immunity is created from wave in wave.The new variants will therefore circulate within populations which have already acquired partial immunity.In absolute terms, they will not be less virulent.But their effects will gradually be less and less important at the level of the community taken as a whole.

Si une obligation vaccinale avait été appliquée dès le printemps, nous ne serions pas dans une situation de crise cet hiver.

Gérard Schockmel,&nbspHRS

The number of cases explodes in Europe, while the holiday season - a sensitive moment, since people come together - approach.What advice seems useful to you?

"The emergency is that unvaccinated people are vaccinating.That those who are eligible to receive their third dose.And that previously infected people are also vaccinated, as more and more studies show that a complete vaccination scheme is necessary for them too.

Do the government's health measures seem to you adapted to the situation?

"If a vaccination obligation had been applied in the spring, we would not be in a crisis situation this winter.Political calculation has been clear: avoid the vaccination obligation so as not to make unpopular.But it doesn't work.On the contrary, this created the division within the company, between vaccinated and non-vaccinés.On the contrary, vaccination obligation is an egalitarian measure for civil and social equality.But our rulers still do not have the necessary courage.It is an endless procrastination.»»

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