[Newsship] Why is Omicron's breakthrough infection better? Scientific facts known so far

Omicron mutations in the COVID-19 virus have thrown the world into chaos this week.

It was on November 25th that the genetic information of this mutation was released by South African scientists.

The first suspected case of omicron mutation was discovered in early November in Botswana, South Africa.

Since the end of November, the world has started to restrict travel and entry, but the opinion of many experts is that the omicron mutant virus has already entered each country before that.

Even before Omicron, the corona virus afflicted humans by showing various mutants.

Among them, like the lambda mutation, there are those that seemed to threaten the world, but were pushed back without much impact.

The reason why this Omicron surprised the world is that the modification of genetic information was much more severe than that of Delta, and the propagation speed was faster.

Symptoms are not known to be severe.

Dry cough, fever, severe fatigue, and headache appeared, but there were no reports of dyspnea, loss of taste, or loss of smell due to the delta mutation corona.

Nevertheless, the initial confusion was heightened by the fact that "you don't know" what will happen when a virus with many mutations, different from the previous coronavirus, enters the human body.

It also raised people's alertness that people who have received conventional vaccines, even booster shots, can become infected with Omicron.

The European Center for Disease Control and Prevention (ECDC) predicted that by the spring of next year, Omicron will become the dominant species among the corona mutations in Europe.

If so, how does the ohmic mutation look different from the delta mutation, so it has more propagation power?

Now, let's learn the physiology of the virus step by step.

1. Why do mutations occur?

- Basic explanation to understand Omicron

Viruses cannot be numbered by replicating themselves while standing alone.

It can reproduce itself only by penetrating into living cells.

Since cells don't just come in and open the door, the virus needs something to do with it too.

On the surface of the virus, things called 'spike proteins' sprout.

This serves as the key that unlocks the door to the cell.

Human cells have something called 'receptors'.

It is easy to think of it as a lock on the door of a cell.

When a virus approaches a cell and pushes a spike protein that matches its receptor, the door opens, allowing the virus to enter human cells and replicate itself.

The cloned viruses come out and infect other cells again, repeating this process.

When these infected cells multiply, our body causes symptoms and becomes ill.

However, the process by which a virus replicates itself and makes countless copies is not as precise as the process of dividing human cells.

Because I make a lot of rough copies quickly, errors are increasing in the process of repeating the genetic information copy.

Think of a game of telling a story.

It is similar to saying that the words are similar at first, but when they reach the end of the line, they become completely absurd.

When these errors accumulate, they become 'mutations'.

The problem is, these mutations can fool the body's immune system.

When a virus attacks cells in our body, our immune system produces 'neutralizing antibodies' to neutralize the virus.

Neutralizing antibodies are customized for each virus.

(The neutralizing antibody to neutralize the hepatitis virus and the neutralizing antibody to neutralize the cold virus are made differently.) The neutralizing antibody overwrites the key (spike protein) of the virus, preventing the virus from opening the door to our cells.

However, the mutant virus has a spike protein that can open the door to our cells by deceiving the existing neutralizing antibody.

Let's think about it this way.

The automatic crime prevention system says, "The robber is the robber with the blindfold masked. Catch it."

The crime prevention system may not recognize this intruder as a 'robber' and let it pass through.

Similar things happen in our bodies.

When the delta mutation first appeared, there was controversy that the existing vaccine was not effective, and that is why.

Viruses invade cells in our body and then destroy those cells, turning them into a virus replication factory.

So what should our immune system do?

The factory must be destroyed to prevent further deterioration.

Immune cells come forward and protect our body by killing virus-infected cells.

The body's immune system fights the virus at several stages.

The first defense is to make antibodies to prevent the virus from opening the door to our cells, but even if the first defense is breached, the immune system of the second and third lines works.

Vaccines also have the effect of strengthening these various immune functions.

Pharmaceutical companies have updated their vaccines to properly identify delta mutations and create new antibodies for them.

It is known that m-RNA vaccines are relatively easy to do this.

2. Why Omicron Mutations Better Trick Antibodies

The problem, however, is that omicron mutations have far more mutations than deltas.

The figure below is a comparison of the spike protein of Omicron and the spike protein of Delta by researchers at Bambino Jesu (Baby Jesus) Hospital in Rome, Italy.

(Spike protein is like a bump on the surface of a virus, and it plays a key role in unlocking the door to human cells. See the previous picture)

Delta on the left and omron on the right, visualization to give you a feeling without any medical knowledge has been

More than 30 of Omicron's more than 50 mutations are contained in the spike protein.

Even in the spike protein attached to the surface of the virus, there is a part called the 'receptor binding domain (RBD)' at the end.

It is a region in direct contact with receptors in human cells.

Omicron has many toxic mutations in this region.

In the case of delta, with only three mutations in RBD, it tricked the antibody in the human body and spread rapidly around the world, but Omicron has 15 mutations in RBD alone.

Then what will happen?

The possibility that Omicron can deceive and open the door to human cells increases with the antibody that was able to neutralize the delta-mutated spike protein.

Therefore, Omicron spreads faster than Delta, and there are more cases of breakthrough infection among those who completed vaccination.

3. Omicron has weak symptoms?

Fortunately, "it is easy to infect" and "does more damage to the body" are not synonymous. So far, it is known that people infected with Omicron usually have mild symptoms. As of the 2nd, 4 out of 5 confirmed cases of Omicron in Korea showed no symptoms, the quarantine authorities said. It was asymptomatic from the beginning, or showed some symptoms such as mild fever, headache, neck pain, etc., but the condition improved and showed no symptoms.

Internationally, there have been no cases of serious illness or death due to Omicron. Even in South Africa, where Omicron has already become the dominant species and is rapidly spreading, mild symptoms are predominant.

Looking at the latest indicators for South Africa, something interesting stands out. From the end of September until recently, the number of new cases per million people in South Africa increased by more than 31%, while the number of new deaths decreased by 79% during the same period.

If you look at the graph of the situation in South Africa after November, the graph of new cases rapidly moves upward. This seems to be due to the spread of omicron mutations, and the death graph for that period shows a stagnant state.

Currently, the trend of new deaths per 1 million people in South Africa is the lowest level since the COVID-19 pandemic in South Africa, and it is lower than that of Korea.

However, it is unknown whether this situation will continue in the future.

This is because not enough time has passed since the Omicron infection started.

SBS Washington Correspondent Kim Soo-hyung interviewed South Africa's Angelique Kuche, who was the first to inform the world about the mutation of Omicron, through an online video.

In this interview, Dr. Kuche was wary of excessive optimism, saying that European media responded only to the first part of his statement, "there were more cases with less symptoms."

In the case of the delta mutation, young and relatively healthy people often pass without severe symptoms, but the elderly, obesity, and people with underlying diseases are doing great damage.

For this reason, as the case of Omicron spreads to Europe and the United States, there is a cautious theory that if people with many risk factors such as the old age, obesity, and underlying diseases are infected, what kind of problem will appear only by observing it.

4. The clash of optimism and prudence

Nevertheless, optimism is starting to emerge. One of the most powerful proponents of optimism is Professor Karl Rottbach, a German infectious disease scientist and member of the National Assembly. According to foreign media reports, Dr. Rotbach, a strong candidate for Germany's next health minister, said, "If Omicron causes relatively less severe symptoms, as South African doctors said, it could be a 'Christmas gift' that can hasten the end of the COVID-19 pandemic. there," he said. Viruses cannot replicate themselves when their host dies, so they tend to evolve in the direction of increasing transmission and weakening toxicity.

If Omicron displaces Delta and establishes itself as the dominant species, humans will be able to escape the fear of COVID-19 to some extent.

However, for Dr. Rotorbach's optimistic outlook to become a reality, there are many things that need to be verified, such as confirming that Omicron does not lead to serious illness, and that people with Omicron must not be reinfected with Delta.

There are many voices who are wary of such optimism.

Professor Neil Ferguson, head of the disease outbreak analysis and modeling group at Imperial College London, UK, said in a parliamentary advisory board: "It should not be concluded that the omicron mutation could have evolved into a mild disease."

"Some viruses in the past have evolved in a way that symptoms diminish over time, but not all viruses have always been that way," he said.

Professor Ferguson added that the coronavirus is only interested in getting back out of the respiratory tract, and it doesn't matter if the host dies after ten days or more.

Professor Ferguson also emphasized that "preemptive and strong measures must be taken early on to limit the spread of radio waves."

Michael Mina, a professor at Harvard Medical School, also voiced this prudence in an interview with the Financial Times.

It is said that we need to spend more time and information to know how this mutated virus will affect the human body.

5. Existing vaccine, should it be correct?

Omicron mutations have many mutations at the tip that bind to receptors on human cells, increasing the likelihood that they can trick the antibody into entering human cells.

One of the main functions of vaccines is to generate antibodies, which have evolved to be more likely to evade.

Let's look at the picture again.

As a result, breakthrough infections often occur in people who have completed vaccination.

In Israel, two doctors who even received the Pfizer vaccine booster shot (3rd dose) were infected with Omicron.

(Of course, it was only mild symptoms.) The

general public reading these articles, especially those who have not yet received the vaccine, may think like this.

"What, is it useless? Shouldn't it be right? Should I wait until it is updated with an Omicron antivirus?"

However, experts say you shouldn't think so.

For now, delta mutations are still rampant.

It is not yet known whether Omicron really causes only mild symptoms or whether Omicron will enter Korea and become the dominant species within this winter.

If you get delta without being vaccinated, your chances of getting serious are much higher than if you get the vaccine.

Therefore, it is beneficial to complete the vaccination even now.

In addition, the vaccine promotes the formation of antibodies, but is also involved in various other immune functions.

A person who has received a vaccine has a higher chance of overcoming the disease as other immune functions work in the second and third lines, even if the cells are infected with the coronavirus.

Dr. Kuche, president of the Medical Association of South Africa, also said he had this experience while seeing patients.

Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, the head of the U.S. quarantine authorities, also said that the existing vaccine will provide some degree of protection against Omicron, and recommended that you not wait for a customized Omicron vaccine to be released and get a booster shot now.

At a press conference at the White House, Fauci said at a press conference at the White House that even if the vaccine was not designed specifically for the new mutation, it could have some effect on the new mutation if it sufficiently enhances the immune response of the body.

This was also the case when delta emerged as the dominant species.

According to a study by the Public Health Department of England published in May, the existing vaccines used up to that time showed a 60-80% prevention rate of symptoms even for the delta mutation, which has begun to rise again.

Fauci said pharmaceutical companies are studying whether they should modify their vaccine designs to be omicron-ready, and that such "modified booster shots may not be necessary," he said.

(So, get it right now.)

WHO chief scientist Sumya Swaminatan also said at the WHO's video press briefing on the 2nd, premised that there is not enough information yet, but said, "We believe that the (current Corona 19) vaccine

as it did with other mutations.

think the

” he said.

6. Will the existing treatment, Omicron work?

If so, will the existing treatment work if the symptoms of Omicron infection become severe?

On October 2, 2020, then-President Trump was infected with COVID-19.

It was a concern around the world what his elderly health would be like. At that time, he received a monoclonal antibody treatment called 'REGN-COV2' and recovered and returned to work within a week.

It was a drug that analyzed and evaluated antibodies in the blood of a person who had recovered from Corona, selected only antibodies that could neutralize the virus, and then used it as a treatment.

This antibody therapy has no effect on patients who are already severely ill who are receiving high-concentration oxygen therapy, so it was urgently approved for use only in the pre-severe transition stage.

Regeneron, a biotechnology company that made this antibody treatment, said that its treatment may have a lower therapeutic effect on Omicron mutations.

This is because antibody therapeutics are the mechanism by which the antibody binds to a specific antigen and neutralizes the virus, so if there is a mutation in the spike, the binding site, the effectiveness cannot be guaranteed.

Molnupiravir, an edible drug developed by pharmaceutical company Merck, works by inhibiting the replication of the virus.

Currently, the external advisory committee of the US Food and Drug Administration (FDA) recommended the FDA for emergency approval, saying that the efficacy of preventing hospitalization and death of this drug is not satisfactory at about 30%, but it is better than not using it.

Professor Paul Hunter of the University of East Anglia, UK, said that if you use these drugs a lot, it may cause a mutation in the virus and result in a decrease in effectiveness, but he does not think Omicron will show resistance to these drugs at this stage.

Currently, high-concentration oxygen therapy or steroid preparations for relieving inflammation are often used for the treatment of severe coronavirus patients.

Such treatment appears to be effective regardless of the type of mutation.

This is because it is not about attacking the virus itself, but about the body's response to the virus.

Dexamethasone, which has been used as an anti-inflammatory drug for about 60 years, has the advantage of being cheap as its patent has expired.

7. What is the most important thing at this stage?

'Delta' response is more urgent

Experts believe that Omicron's spread is so fast that it is impossible to keep up with the spread by only following the path of confirmation and blocking it.

He also said that as Omicron spreads in the future, it is necessary to focus on reducing the severe damage of high-risk groups rather than exhausting limited quarantine resources to track and isolate all confirmed patients.

In summary, the booster shot of the existing vaccine has a greater benefit from inoculation even when both delta mutation and omicron are taken into account.

Omicron mutation will have to take some time and wait for more research results, but it doesn't seem like a panic problem.

In writing this article, words such as 'shock', 'fear' and 'helpless' were intentionally excluded.

(Composition: Senior Correspondent Lee Hyun-sik, Reporter Jang Seon-i / Designer: Myung Ha-eun, Park Jeong-ha)