More infection, less severity: Omigron’s portrait gradually emerges

Very contagious, undoubtedly less malignant: a month after being identified in South Africa, we begin to better understand the Omigran variant, which could not tell us how much it will change the face of the COVID-19 epidemic.

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What do we know about him?

Compared to the delta variant, “its prevalence is very high and its intensity may be low, but we do not know to what extent,” Jean-Fran்கois Delphrasi, chairman of the Science Council, which leads the French government, said briefly on Thursday.

Omigron is progressing dramatically in many countries, and cases are doubling every two to three days, with previous variations unheard of.

This is already the majority in Denmark or the United Kingdom, where we have over 100,000 cases daily and are preparing to do so in other countries, including France. Thus he uses it more favorably than the delta he previously dominated.

At the same time, preliminary studies this week from South Africa, Scotland and the UK show that fewer are hospitalized than the Omicron Delta.

According to these data, more incomplete and should be handled with caution, the Omicron may be 35% to 80% lower than the delta.

Important point: It is not known whether this low severity came from the intrinsic characteristics of the variant or whether it affects people who are already somewhat immunocompromised (vaccinated or previously infected).

Hospital effects?

This is the big question that remains unanswered.

The equation depends on two unknowns: will the decrease in the intensity of the omigran be sufficient to compensate for the fact that it is highly contagious?

WHO (World Health Organization) Director-General Tetros recently warned that “although Omicron causes less severe symptoms, the number of patients could again overwhelm unprepared health systems.” Adhanom Ghebreyesus.

In South Africa, this impact seems to be limited, but this finding cannot be extended to countries in the Northern Hemisphere where the population is high.

Since this country on the European continent was first hit by the Omigron wave, scientists expect a lot from hospital data coming out of the UK in the coming days.

“It’s very important to see what happens in London next week. It will teach a lot about the severity of the disease caused by Omigran, said Professor Arnaud Fontaine, a member of the French Science Council, on Thursday.

What about vaccines?

Mutations in omigran allow the antibody to reduce immunity to the virus. Effect: It can contaminate a large number of vaccines (and re-infect those previously infected with the virus).

Numerous laboratory studies have shown that the antibody level of Omicron in the face of those vaccinated by the Chinese vaccine AstraZeneca or Sinovac used in Pfizer / BioNTech, Moderna and fifty other countries is declining.

As a stimulant, a booster dose can significantly boost antibody immunity. After Pfizer / Bioendech, Moderna made the announcement on Monday, and AstroZeneca on Thursday. But there is one important information: we do not know how long this effect will last.

Conversely, a study by Hong Kong researchers published on Thursday shows that even with a booster, Sinovac does not produce enough antibodies.

Finally, we do not know the answer to the fifth novovax vaccine approved in the European Union on Monday. This was actually tested in clinical trials when alpha and beta variants were more common.

But all this does not mean that vaccines are no longer effective. Because antibodies are only part of the immune response, they contain cells called lymphocytes. It is very difficult to measure, and this “cellular immunity” plays a very important role, especially against severe disease forms.

Therefore, a study presented in South Africa in mid-December suggests that Pfizer-BioNTech may be effective against extreme forms caused by Omicron, before the booster (so maybe more).

Confused?

Although the Omicron wave did not drown the hospital, this variant could still wreak havoc in many countries.

Its unprecedented epidemic could actually lead to an explosion of “non-existent” by isolated activities, so “disruption” of many sectors (supermarkets, transport, hospital, school …), the French Science Council warned on Thursday.

“This is really new data that we do not have with other waves, which is linked to the diffusion speed of Omigron,” said Professor Olivier Currin, a member of the organization.

To control this anomaly, it may be necessary to relax the isolation rules, considering that Omicron appears to cause less intense covid forms.

This is exactly what the British government did on Wednesday, reducing the period of isolation in the UK for those vaccinated against COVID-19 from ten to seven days.

Tito in South Africa, a scientific council there, recommended that the isolation period for symptomatic patients be reduced from ten to seven days.

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