COVID-19 Omicron variant is really more terrible than Delta variant?

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COVID-19 Omicron variant is really more terrible than Delta variant?

The emergence of various mutations is almost inevitable when the global COVID-19 epidemic does not subside.

In nearly a year, we have seen Alpha come out, Beta and Gamma dominate one side, and witnessed Delta staged a global COVID-19 virus strain with a thundering trend, almost becoming the only virus strain in the world.

We see the profound effects that too many mutations can bring, and we naturally worry about the next more terrifying mutation. Recently, a mutant strain B.1.1.529 in southern Africa has become the next mutation that many people worry about.

The World Health Organization even convened an emergency meeting on November 26 to directly upgrade it to a “Variant of Concern” (VOC), code-named Omicron, equal to Delta.

1. Omicron is more terrible than Delta?

Delta’s impact on the global epidemic is profound and extensive.

It is not the virus strain with the most serious immune escape: Existing vaccines are still highly effective against it, but a certain amount of immune escape coupled with extremely fast transmission speed makes the difficulty of prevention exponentially increased .

The spread is too fast, and a large number of unvaccinated people are unable to fight back, causing a large number of infections in many countries; sudden large numbers of cases have caused a sharp increase in the amount of virus in the “environment” where all people live, even if they are vaccinated People who have been vaccinated are constantly being “attacked” by the virus, making it difficult to be safe; rapid replication makes the peak infection load similar to that of unvaccinated cases, further increasing the difficulty of blocking the spread of the virus.

The combination of these factors has caused the world to sink into the Delta quagmire. It is also because of the power of Delta that we see a mutant strain called “the next Delta” or “more Delta than Delta” from time to time.

However, most of these have hype elements, such as Lambda and Delta+, which are “big thunder and little rain”. After basically causing a certain impact in a region, it was marketed by the media and then disappeared.

Why does this happen? The reason is that these virus strains have not shown the ability to replace Delta. For any mutant strain to gain a foothold, it must be able to compete with Delta, which has an absolute advantage in the world .

If a mutant strain has no advantage over Delta—especially an advantage in spreading speed, it is likely to be directly competed by Delta.

This is the case with Lambda. After it appeared in some areas, it could not spread. In places where Delta was also present, it was suppressed by the latter.

Why do some scientists sigh that “the more terrible vairant is really coming”? A big reason is that South Africa did a good job tracking mutant strains.

For example, Tulio de Oliveira, an epidemiologist in South Africa, said that the rapid growth of B.1.1.529 in the area is worrying.

Figure: Detection and tracking of mutants in South Africa. Twitter from Tulio de Oliveira

It can be seen that since November, in the South African virus genome test, the proportion of B.1.1.529 has risen rapidly and has surpassed Delta.

A few weeks ago, the number of new cases per day in South Africa was only a few hundred, but now it has suddenly increased to more than two thousand.

Guateng Province, including the large city of Johannesburg, has more than 1,000 new cases per day, of which more than 90% are estimated to be B.1.1.529 mutants, and the positive detection rate has soared from 1% to 30% within three weeks.

This has to make people worry about whether B.1.1.529 is more competitive than Delta .

If it is indeed more competitive than Delta, it will naturally pose a great threat to epidemic prevention.

Compared with Lambda and Delta+, B.1.1.529 is more like a real wolf.

2. The number of mutations is worrying

But B.1.1.529 has caused such alarm that its proliferation in South Africa and other places is only a factor.

It should be noted that the recent Delta epidemic in South Africa is going downwards, and the cases are not at the peak.

In this case, the number of B.1.1.529 cases exceeds Delta and causes the epidemic to fluctuate, which is not enough to show that it is really faster than Delta.

The more worrying thing about B.1.1.529 is that this mutant strain has too many mutations .

The most interesting mutation of the COVID-19 mutation is the mutation on the spike protein (Spike).

The spike protein is the key to the virus entering the human body.

The mutation on it may allow the virus to better integrate with human cells-corresponding to faster transmission, or it may be established by the body against the original virus strain (including vaccines based on the original virus strain) Decreased immune memory effect-corresponding to immune escape, that is, more secondary infections and decreased vaccine effectiveness.

B.1.1.529 There are as many as 35 changes in the known amino acid sequence of the spike protein.

The mutation is in the binding region (RBD) of the spike protein and the human ACE2 receptor, which is also the key part of the neutralizing antibody.

The number reached 15. In contrast, Delta has 10 mutations on the spike protein and 2 RBD mutations.

COVID-19 Omicron variant is really more terrible than Delta variant?

Figure: The mutation on B.1.1.529, the whole green is the spike protein, and the red is the RBD. Twitter from Tulio de Oliveira

Among so many mutations, some we have observed in other mutant strains and know what kind of trouble it may cause.

For example, T478K and P681H are on Delta. The former contributes part of Delta’s immune escape, and the latter is The key to the rapid spread of Delta. N501Y is one of the reasons that makes Alpha more transmissible than the original virus strain.

Beta is the virus strain with the most serious immune escape so far, the E484K mutation is indispensable, and the E484A mutation is in the same position on B.1.1.529.

In addition to a collection of mutations that we know are not fuel efficient, B.1.1.529 has many mutations that we don’t know what to do.

Therefore, it is not yet possible to accurately assess the characteristics of this mutant strain in terms of transmission speed and immune escape .

However, after so many mutations have accumulated on the spike protein, we have to worry about whether the spike protein of this mutant strain has been too different from the original virus strain.

The human body’s immune protection against the COVID-19, whether it is natural infection or vaccination, comes from the memory of the spike protein.

When the spike protein has accumulated so many mutations, we have to worry that the immune system can still recognize this unrecognizable Is it a new strain?

It can be said that although we do not know whether the large number of mutations make B.1.1529 faster and stronger, or how fast and strong, but only with so many mutations and the expansion in South Africa and other places, we can say yes. Mountain rain cannot be overemphasized.

This is also the main reason why the WHO directly upgraded it to a “worrying mutant” (VOC).

3. How to deal with it?

First of all, our knowledge of B.1.1.529 is still very limited. Yes, there are so many mutations that are worrying, but to say that this mutation must be more spread than Delta, has made the vaccine ineffective, and it is suspected of grandstanding.

Scientists also need time to do relevant research and collect evidence. Even if there may be immune escape, it should be seen that according to previous studies of mutant strains, the effectiveness of vaccines for mild cases has decreased, and the more critical protection against severe cases is not affected much. So there is no need to create panic for no reason .

Of course, analysis of existing vaccines and therapeutic drugs, especially monoclonal antibody drugs, will be extremely critical to the effectiveness of B.1.1.529.

However, it is relatively easy to modify mRNA vaccines and adenovirus vaccines based on mutations. Both Pfizer/BioNTech and Moderna have indicated that they can provide a replacement vaccine against a mutant strain within 3 months .

Monoclonal antibody drugs are indeed very challenging to face the multiple mutations on the spike protein, especially RBD, but B.1.1.529 has not yet spread globally.

Like the nearly 100,000 Delta infected people in the United States every day, there is really no need to worry about antibodies.

The medicine is ineffective. As for oral antiviral drugs, the target of action is different from antibody drugs, and they are less likely to be affected by immune escape mutations, and they are not drugs used on a large scale. It is too early to worry about them.

Second, the focus of attention should be the virus itself. I have seen some articles commenting on South Africa’s “Gu”.

That is very absurd and extremely ignorant. South Africa has been doing very well in monitoring mutant strains.

The timely detection of Beta strains was also due to monitoring efforts.

As a country with relatively limited resources, it is not easy to keep trying to track changes in the viral genome in the country, and to adhere to the principle of disclosure after discovering new mutations, and to publish them in a timely manner even if they may suffer discriminatory treatment.

In the face of a potentially threatening mutant strain, we may indeed need to impose restrictions on international navigation, but these measures should be based on respect and understanding, cooperation and mutual assistance, and should not be out of indifference and selfishness.

In particular, South Africa has found so many cases of B.1.1.529. One prerequisite is that they have been carefully monitored.

Some of the viral genome national long-term monitoring can not keep up the rhythm of the investigation do not think they did anything to it complacent.

In the end, gain a wisdom from eating. The emergence of B.1.1.529 must make the world (especially developed countries) reflect on the current epidemic prevention strategies, especially the issue of vaccine distribution .

Why do B.1.1.529 virus strains with many mutations appear? It must come from the continuous replication of the virus.

In particular, immune-suppressed people have weak ability to eliminate viruses and are more likely to accumulate mutations.

It cannot be ruled out that B.1.1.529 has such an origin. South Africa’s current vaccination rate is less than 25%, and a large number of young people are not vaccinated.

Many cases of B.1.1.529 are concentrated in local young people. In the entire African continent, South Africa has a high vaccination rate, and the overall vaccination rate in Africa is between 7-8%.

There are still a large number of HIV infections in Africa, which means that there are many immunosuppressed people, which further increases the potential risk of virus mutation.

At a time when the world’s full vaccination rate is close to 43%, it is shameful to have an inoculation rate of less than 10% on one continent.

In particular, some developed countries are hoarding vaccines and rushing to promote booster injections, which is ethically and scientifically absurd.

When some countries proposed that the mRNA vaccine should be boosted by the whole people, I made it clear that this is very short-sighted .

The use of a large amount of vaccine resources on boosters that have limited effects on the improvement of the epidemic will make it more difficult for many developing countries to vaccinate.

When the virus continues to spread, replicate, and mutate in countries with low vaccination rates, it is very likely that a more harmful mutant strain will appear.

At that time, let alone a booster shot, you will get 7 shots and 8 shots in vain.

The emergence of B.1.1.529 brings such a threat. Previously, media reported that the United States had stockpiled nearly 300 million doses of vaccines and 200 million in Europe.

If it is really because of B.1.1.529, a new vaccine must be made, and it is not the vaccine that is stored, but the waste product.

If you distribute these vaccines that you can’t use more to the countries and regions in need, maybe B.1.1.529 won’t have a chance to appear.

It’s never too late to make up for it. To overcome the epidemic, we must view the epidemic from a global perspective.

The behavior of some countries in the distribution of vaccines and medicines urgently needs to be changed .

Otherwise, even if B.1.1.529 is not the “wolf” that can let previous vaccination efforts be abandoned, we It was just waiting for the attack of the next beast.

Finally, no matter how the virus mutates, masks and social distance are absolutely resistant to mutations.

The scientific epidemic prevention policy itself must be comprehensive, and testing, drugs, and non-drugs must be considered, so that it will not be easily broken down by a mutant strain.

Reference:
https://www.who.int/news/item/26-11-2021-classification-of-Omicron-(b.1.1.529)-sars-cov-2-variant-of-concern

COVID-19 Omicron variant is really more terrible than Delta variant?

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