Montmorillonite powder is out of stock! The new strain XBB mainly attacks the gastrointestinal tract? Rumor! Don’t believe it!

At the beginning of 2023, we saw various hot searches about the XBB strain on the Internet, including some rumors, such as the rumor that the XBB strain mainly attacks the gastrointestinal tract and causes diarrhea. So many people started to stock up on montmorillonite powder and rehydration salts.

Image source: Internet

In fact, since the outbreak, many rumors have appeared on the Internet. After the old rumors are dispelled and everyone knows the truth, new rumors will emerge again, and every time a new rumor appears, everyone will feel at a loss. In the face of the new coronavirus epidemic and the rumors that come with it, what should we do? And what everyone is most concerned about is why it is said that "XBB strain mainly attacks the gastrointestinal tract" is a rumor? I believe that after reading this article, everyone will be able to distinguish such rumors.

01

What exactly is XBB.1.5?

XBB.1.5 was recently separated from XBB by the U.S. Centers for Disease Control and Prevention. Because most XBB in the United States is actually XBB.1.5, XBB.1.5 is currently the most prevalent virus strain in the United States.

Image source: Internet

So are there any special symptoms for XBB.1.5?

No. Why can XBB.1.5 become the mainstream mutant strain in the United States? Because it has a strong immune escape ability. Many people in the United States have been infected with the new coronavirus, and many have been infected with various substrains of Omicron (BA.1, BA.2, BA.5 and BQ.1, etc.) after receiving the highly effective vaccine, which has laid a very strong immune foundation. Only strains with stronger immune escape can establish an advantage in the United States, and XBB.1.5 has gained an advantage in the competition with BQ.1 and BA.5 because of its stronger immune escape ability, accounting for a larger proportion of new infections.

02

What exactly is “immune escape”?

The human body's immune protection against the new coronavirus mainly comes from the immune recognition of the new coronavirus spike protein, and the immune protection against infection mainly relies on neutralizing antibodies against the spike protein - this has a scientific basis. The new coronavirus infects human cells by binding to the spike protein and the human ACE2 receptor. Neutralizing antibodies block this process, thereby naturally blocking the infection.

We say that XBB.1.5 and other Omicron mutants have strong immune escape because they have accumulated new mutations on the spike protein, which has better immune escape from neutralizing antibodies. Such mutations do not need to be particularly large in number. In many cases, only a few key amino acid sites need to change to significantly enhance immune escape. This is the case with XBB.1.5. Don’t be fooled by the fact that the names of the mutants are much more complicated now. The actual location and number of mutations have not changed so drastically.

Why can a small number of mutations on the spike protein have a greater impact on neutralizing antibodies? Because the sites recognized by antibodies, where they bind to the spike protein, are limited (the location of neutralizing antibodies is even more limited, and they must just block the spike protein from binding to the ACE2 receptor, similar to the positioning in basketball, where you can't just stand anywhere on the court to successfully position yourself). Mutations at sites where neutralizing antibodies are highly concentrated naturally produce results that are like a small effort to achieve a great result.

03

Knowing this, rumors will be dispelled

The above content is the basic concept introduction when we introduce the immune escape of the new coronavirus, and XBB.1.5 is no exception. Knowing this, let's look at the rumor that XBB.1.5 specifically attacks the cardiovascular and intestinal tract. This mutant strain has become mainstream in the United States because the mutation on the spike protein has reduced the effectiveness of neutralizing antibodies and is prone to breakthrough infection or secondary infection. Does it have anything to do with which organs are attacked?

Copyright image, no permission to reprint

How does the novel coronavirus invade human cells? As mentioned earlier, the spike protein binds to the human ACE2 receptor. The same is true for XBB.1.5. The organs it invades also depend on the distribution of ACE2 receptors. Like previous virus strains, it will mainly attack the respiratory tract. How come it specifically attacks the cardiovascular and intestinal tract?

Therefore, do not believe or spread the rumor that XBB.1.5 specifically attacks the cardiovascular and cerebrovascular systems and the intestines, and do not blindly follow the trend and stock up. If it is replaced with another mutant strain in the future, and it is said that it specifically attacks a certain area, has special symptoms, and requires special drugs, do not believe it.

The immune escape of Omicron virus strains, including XBB.1.5, is mainly immune escape from infection. Prevention of severe disease is less dependent on the existing neutralizing antibodies in the human body and is less affected. Vaccination and past infection can therefore reduce the risk of severe disease.

Therefore, learning to discern information, referring to reliable sources of information, and not being misled by online rumors is also an important means for us to fight the new coronavirus. It can help us better understand the new coronavirus as an enemy, and it can also help us have a better mentality when we are infected with the new coronavirus.

Let us start with ourselves, do not believe in rumors, do not spread rumors, and pass on correct and scientific information to our friends and family. Do not get information from unreliable places, and recommend reliable information sources to people around you.

I wish you all success in defeating the virus!

Author: Y Bo

Review | Jin Dong, Associate Researcher, Institute of Infectious Diseases, Chinese Center for Disease Control and Prevention

If you have questions about the coronavirus

Especially those who hope to get analysis and answers to rumors and rumors related to the epidemic

Please leave us a message

The cover image and the images in this article are from the copyright library

Reproduction of image content is not authorized