Omicron, what could happen with the Covid variant (not necessarily bad news) – Corriere.it

Omicron, what could happen with the Covid variant (not necessarily bad news) – Corriere.it
Omicron, what could happen with the Covid variant (not necessarily bad news) – Corriere.it
from Cristina Marrone

A highly contagious new variant could have dire consequences. But if it were also to be less aggressive than Delta, it could lead to a peaceful coexistence with the virus, which would effectively mark the end of the pandemic.

The arrival of Omicron, the new variant of coronavirus identified for the first time in Botswana and South Africa and now present in Europe (including Italy), in the United States and in many other countries of the world has been greeted with great anxiety and fear. Many nations have closed their borders, preventing the landing of flights from South Africa and other African regions, a choice disputed by many scientists (and by the WHO) because the closing attitude does not encourage countries to communicate the new variants quickly if they are then punished with isolation. The World Health Organization quickly identified Omicron as variant of concern and today the question still without a clear answer: will vaccines also defend us from Omicron?

The effect of Omicron on the pandemic

The truth is that it is not said that Omicron’s arrival is indeed bad news. The effect of Omicron on the course of the pandemic will depend on three of its characteristics: his transmissibility, his ability to evade the immune defenses induced by vaccines and his virulence, that is, whether it will cause a more serious disease.

If Omicron were to be found to be easily transmitted from host to host, evading neutralizing antibodies and causing severe disease then the situation would indeed be complex and the consequences could be dire.

But if Omicron turns out to be a super contagious variant but causes mild symptoms, then it could also be good news, just in time for Christmas. Rachel Gutman su The Atlantic.

Because we will live with Covid

now the opinion of many that living with the coronavirus is now inevitable. Vaccinating the whole of humanity does not seem like something easily feasible. Even rich countries that have had large quantities of vaccines available have not managed to immunize 100% of the population, given the large number of people who refuse the vaccine out of fear or ideological reasons.

I Commercial vaccines are unfortunately not sterilizing: still reduce the risk of hospitalization, serious illness or death (albeit with lower percentages compared to the Alpha variant), but they do not completely prevent transmission. Plus theirs effectiveness is reduced in considerably shorter times (3-4 months) compared to the time needed to vaccinate the population, making it practically impossible to always have the right timing between high percentages of immunized people in coincidence with a high incidence of the virus.

Finally, even if every human on Earth gains vaccine or infection immunity, the virus could retreat into one of its animal hosts and then return to mutated humans, in what scientists call reverse zoonosis.

Unable to eradicate the virus

Many scientists have got their hands on the future of the pandemic. No one now believes that eradicating Covid is a realistic goal.

Also Anthony Fauci, immunologist advisor to the White House at the beginning of October had declared: It will be very difficult, at least in the near future and perhaps never, to eliminate this highly transmissible virus. Since this enemy cannot be defeated, we would all have a better chance of survival if he were armed with a slingshot rather than a cannon. The Atlantic.

What happens in South Africa

The very first data arrived from South Africa on the Omicron infection reported cases with mild and less severe symptoms of Delta (although it should be remembered that the African population is decidedly younger than the European average and therefore could be less susceptible to complications caused by Covid).

However, the spread of the Omicron variant in South Africa is causing a exponential increase in infections. The latest bulletin speaks of 11,535 infections and 44 deaths, with increasing hospitalizations (274 more patients in hospital in one day) and an increase in infections of 365% compared to last week. Cases of reinfection are also reported. S.

According to a preliminary study, the risk of reinfection in this Omicron wave appears to be 2.4 times higher than the first wave, but it is not yet known whether the immune leak also involves the vaccinated and we will have to wait for the neutralization tests in progress. In Europe so far there have been no serious cases or deaths from the Omicron variant – although there are only about sixty confirmed cases.

Hope: milder and more transmissible

If Omicron really turns out milder than Delta would certainly be good news. But if it turned out to be both milder and more transmissible it might even be great news.

When two variants circulate, the one that infects more people and more quickly tends to dominate.

Omicron could also mark the end of the pandemic fear – he comments Arnaldo Caruso, president of the Italian Society of Virology – and become the beginning of the phase awaited by the scientific community around the world: a peaceful relationship between man and coronavirus. If the new variant proves to be truly more transmissible, but less aggressive, it could be thereadaptation of Sars-CoV-2 that we were waiting for.

Immune escape

Omicron may prevail either because it replicates faster in its human hosts and spreads more effectively among them, so it becomes more contagious or because it more skillfully evades acquired immunity, infection or vaccine, explains to The Atlantic. Samuel Scarpino, del Pandemic Prevention Institute della Rockefeller Foundation.

Speaking of immune runaway may sound alarming: the idea of ​​starting over after two years of hard struggle against the virus does not seem very reassuring. No one after getting vaccinated would want to be told that they are still susceptible. For a variant that causes reinfection but does not lead to severe disease that requires ventilatory assistance, it may not be as bad. If we find that Omicron bypasses vaccines but ultimately causes minor disease, we are probably heading in the right direction, he says Elizabeth Halloran, biostatistica del Fred Hutchinson Cancer Research Center.

The goal of the virus: coexistence

The goal of viruses, especially respiratory viruses such as Sars-CoV-2, is to infect as many hosts as possible, exploiting the organism to multiply and continue to circulate. It is not convenient for the virus to eliminate the host by behaving aggressively (he would die too): it is better to look for one domestic partnership that allows him to survive. Fewer symptoms or even no symptoms – points out Arnaldo Caruso, who is also full professor of microbiology and clinical microbiology at the University of Brescia – plus a virus has the possibility of transmitting itself, of continuing its course and of prevailing in its most contagious form. , faster but milder, on all other variants. this is perhaps happening, even if to date the available data are few and all still to be verified and understood.

Will we lose acquired immunity?

It is possible that with a super contagious and at the same time super mild Omicron those who become infected do not develop sufficient immunity to defend themselves from a subsequent infection. Mild cases of Covid may not stimulate the immune system to produce as many antibodies as would develop against severe disease.

Studies on the subject have not been univocal and there are studies in which it is shown that a mild infection does not necessarily preclude a robust immune response and instead, T cells may come into play that can fight the invader the next time it arises.

Coronavirus like a cold

The hypothesis that the coronavirus could turn into a cold over the years, becoming an endemic disease has been put forward several times by researchers. Last January an article published in Science based on the study of other human coronaviruses predicted that Sars-CoV-2 would one day become endemic. If SarsCoV2 followed in the footsteps of other coronaviruses responsible for the common cold – the researchers concluded – the infection could significantly diminish: according to forecasts, it could strike for the first time within 3-5 years of age with modest symptoms, and then recur in adulthood, but even more lightly. In other words the coronavirus has all the characteristics to become endemic: that is, it will be a pathogen that it circulates at low levels and will only rarely cause serious illness.

Waiting for the data

To date, Delta has proved to be an ideal variant: transmissible enough to dominate the more dangerous variants such as Beta and Gamma but generally its virulence can still be controlled by vaccination.

Only in the next few weeks will it be possible to find out if Omicron will have its load of positivity (and it would be a nice Christmas present) or if it will prove to be an immune escape variant capable, among other things, of causing more serious diseases.

December 4, 2021 (change December 4, 2021 | 17:34)

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