Will Omicron Destroy the Delta Forever?

Six weeks after Omicron was first reported in South Africa on November 24, the corona virus is deleting the delta species. Does this mean that the omicron will destroy the delta forever, or will the two sides be in circulation forever?

Evidence suggests that Omicron’s domination of the Delta is certain, and it is unlikely that Delta will be able to regain its abundant abundance even after Omicron no longer has a host to infect.

Based on analysis Assassination of BedfordIn many US states, omicrons currently make up 99% or more of coronavirus infections, according to biostatistics and biologist at the Fred Hutchinson Cancer Research Center in Seattle.

Bedford and colleagues tracked the genetic sequences collected from Covid 19 patients and found that the number of omicron infections exceeded delta infections from mid-to late December. Even in states with relatively small numbers of omicrons, this species is responsible for 80% or more of the cases.

When the omicron first appeared, researchers were concerned that both species would circulate in society. It was clear that omicron was spreading very fast; But it was not clear whether this was due to its better ability to spread or whether omicron could have escaped immunity in vaccinated or previously infected individuals.

While Omicron has been shown to escape immunity and is two to three times more transmissible than Delta, this explains why Omicron’s global dominance. Dr. Shaw PillaySaid a professor of medicine at Harvard Medical School:

If you put them in direct competition, as seen in the crowd, Omicron will win. Omicron is more likely to be infected than delta; Thus, the delta slowly disappears and the omicron dominates society.

In general, omicrons are less severe than lungs because of pre-existing immunity in the population and a preference for proliferation in the bronchi or airways. This means that overcoming it can ultimately lead to fewer deaths than when the delta is in the community.

According to experts, the huge wave of omicron infections may eventually provide some protection against future species and bring us closer to the end of the world. However, new species are likely to emerge, and a form of the virus will remain with us for the not-too-distant future.

Cross immunity

Omicron’s spike proteins vary by decades compared to delta spike proteins. Spike is an important protein that the virus uses to enter cells. This protein is also targeted by antibodies produced by Covid 19 vaccines.

Accordingly, even if a person has been previously infected or vaccinated, his or her immune system will not produce antibodies that are well compatible with Omicron. Instead, his antibodies are more suitable for targeting the spike protein of the early SARS-CoV-2 species. However, many amino acid forms are still common between the two spikes; Therefore, researchers expect that there is a level of cross-safety between the two species.

A small study of South Africa that has not yet been reviewed by experts has shown that there is cross-reactivity. This study examined the immune responses in vaccinated and unvaccinated individuals infected with omicron.

Researchers with guidance Alex Seagal Eight unvaccinated and seven unvaccinated people with post-vaccination infections were studied at the African Health Research Institute in Durban, South Africa. Three vaccinated patients received two doses of Pfizer vaccine, three received one dose of Johnson & Johnson vaccine, and one received two doses of Johnson & Johnson vaccine.

The researchers took blood samples from infected people for about four days after the disease and then two weeks later. They then exposed the corona virus in the laboratory to the blood samples and tested the body’s first line of defense, neutralizing antibodies. These antibodies bind to the virus and prevent it from entering the cells.

As expected, the ability to neutralize omicrons in blood taken two weeks after illness was 14.4 times greater than in blood taken early; But Delta neutralization also increased 4.4 times. This means that omicron infection should also increase protection against delta.

This result was not surprising for Pillay. When the body is exposed to the corona virus, the immune system produces antibodies that will detect the shape of different parts of the spike protein. Some of these areas are similar in Omicron and Delta; Therefore, some anti-omicron antibodies will also be effective against delta.

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This is the mechanism by which the booster dose of the vaccine works. A recent study with guidance Alejandro Balage, An immunologist at the Massachusetts General Hospital Ragon Institute and the Massachusetts Institute of Technology and Harvard, and published in the MedRxiv pre-published article database, It was only four to six times less responsive to the main strain of the coronavirus.

This is important given that the booster continues to provide the immune system with the primary spike protein. According to Pillay, the re-introduction of the vaccine greatly increases the level of antibodies. Some of these multiple antibodies have cross-reactivity and bind to similar protrusions on the omicron and delta. Adequate concentrations of antibodies against these common forms can still inhibit infection; Even if many of the antibodies produced are not caused by a specific omicron vaccine.

Transmission dynamics

The apparent gentleness of the omicron compared to the delta is a promising aspect of its dominance in the population. In any individual, getting omicron is probably less risky than having delta (especially for vaccinated people). The absolute number of infections after omicron vaccination is greater than the number of such infections during the delta wave; That means the next few weeks will be tough, and the massive influx of people, all of whom become infected all at once, will put pressure on health care resources.

As of Jan. 6, there have been 119,661 patients with Covid hospitalized in the United States, surpassing the Delta wave peak of 97,811 and approaching last winter’s peak of 133,268, according to Our World in Data. Has been. In the coming months, however, the Omicron wave will give people new immunity to the Corona virus; Including cross safety, which may protect them from serious consequences in the event of the emergence of another species.

A study in South Africa shows why the natural immunity of omicrons alone is not enough to protect individuals from re-infection or new species. The study showed stronger antibody responses to omicron infection in previously vaccinated individuals, and more variable responses were seen in unvaccinated individuals.

In some people, the infection elicited a strong antibody response, and in others, a relatively weak antibody response. This may be because the virus may activate proteins that turn off or inhibit the optimal immune response. Vaccination does not do this. Neutralizing antibodies from infection, like vaccine-neutralizing antibodies, decrease over time.

Finally, a combination of vaccines and omicrons can help move the world from globalization to the localization of the disease; This means that most people will be somewhat immune to the coronavirus, and the increase in infections will be less catastrophic in terms of hospitalization and serious illness and death. However, reduced immunity probably means that copies of the corona virus will remain, and people may become vulnerable to serious consequences by staying away from past infections or booster vaccines.

It is also possible for a species to emerge that can better escape safety. In the future, antiviral drugs such as Paxlovid Pfizer, which has appeared in promising clinical trials, are likely to be an important factor in reducing the damage caused by the continued circulation of SARS-CoV-2.

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