The reason for the positive nucleic acid test in the vaccination environment has been found! The virus is obviously dead, why can it still show positive?

Recently, some provinces have detected positive nucleic acid of the new coronavirus in environmental samples collected and tested by new crown vaccine vaccination units.

A positive result means a "red light" when screening infected people and the environment, indicating that the new coronavirus may be present.

So, does the "red light" around the vaccine this time mean that the virus has "resurrected"? Will it bring infection?

To this end, the Chinese Center for Disease Control and Prevention conducted further research and analysis on samples and vaccine fluids, and on January 24 issued the "Technical Recommendations on Environmental Sample Monitoring in New Coronavirus Vaccination Units" (hereinafter referred to as the "Recommendations"), which stated that the cause of the positive result was the dead virus strains in the vaccine fluid.

So the question is, if the virus is dead, why can it still show positive? How can we prove that it is really dead?

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How did it die?

To prove that the virus is dead, we must first figure out how it died.

The COVID-19 vaccine currently being administered is an inactivated vaccine, which, as the name suggests, “kills” the virus.

Killing viruses is not about using "knives and guns" in the macroscopic world, but about using chemical methods to inactivate the virus's life-active molecules.

For example, β-propiolactone does not act directly on proteins, but can enter the virus and destroy its nucleic acid. This is like giving the virus arsenic, which will cause it to die.

For example, formaldehyde can destroy the amino-containing nucleotide bases (such as A, G, U) in the virus nucleic acid, and can also destroy the virus's outer shell protein. This is like pouring sulfuric acid on the virus, causing it to die "both physically and mentally."

"There are many kinds of virus inactivators." Yang Xiaoming, chairman of Sinopharm Group Sinopharm Biopharm, once told a reporter from Science and Technology Daily when he was popularizing inactivated vaccines. For inactivation alone, Sinopharm promoted the research on the inactivation effects of four or five different inactivators at the same time during the research and development. Inactivation cannot be insufficient, if there are still live viruses, it will cause infection, and it cannot be "overdone", if the inactivation destroys the antigens on the surface of the virus, the vaccine will be less effective.

Inactivation is like "eradicating the weeds on tofu", you have to not break the tofu and you have to eradicate the weeds.

In order to determine whether the drug is "completely dead" and whether it is still effective, the researchers conducted a large amount of experimental verification during the research and development process, and explored the optimal type of inactivation agent, and the parameters such as the inactivation time, temperature, and dosage control for production.

It's really dead.

After production and before the vaccine arrives at the above-mentioned vaccination units, it still needs to be inspected. A basic requirement for passing the test is to verify that the virus is indeed dead.

my country implements a strict vaccine batch release system. At a press conference held by the Joint Prevention and Control Mechanism of the State Council on December 31, Chen Shifei, deputy director of the National Medical Products Administration, said that the drug regulatory authorities will issue batch releases for each batch of COVID-19 vaccines shipped out of the factory. At present, the drug regulatory and inspection agencies in Beijing and Hubei Province have been authorized to undertake the batch release of COVID-19 vaccines.

That is to say, every vaccine that enters the vaccination process has undergone rigorous data review and laboratory testing for the same batch of vaccines.

On December 25, 2020, staff members inspected the product packaging quality in the sub-packaging workshop of the inactivated COVID-19 vaccine at the Beijing Institute of Biological Products of Sinopharm Group. Photo by Xinhua News Agency reporter Zhang Yuwei

A paper titled "Key Points in the Production Process of Inactivated Virus Vaccines" written by researchers from the Center for Drug Evaluation of the National Medical Products Administration shows the stringent requirements for virus inactivation testing: detailed information on virus inactivation verification must be provided, and sensitive cells can be blindly propagated for three generations, with each generation of cells tested. The most sensitive detection method should be used to verify the absence of live viruses. The method should have sufficient sensitivity and repeatability, and duplicate samples should be taken at each sampling point...

In summary, the inactivated vaccine must be repeatable, with double-sample verification, and ensure that there is no live virus in the third generation. Some verifications also need to be assisted by animal testing to prove from multiple angles and levels that the virus in the inactivated vaccine is indeed dead.

As long as "pairing" can show Yang

So, since the viruses in the inactivated vaccine are completely dead, why do nucleic acid tests on environmental samples still show a “red light”?

The principle of nucleic acid testing can be imagined as two small insects chewing on willow leaves on both sides. As long as the willow leaf is "to their taste", the small insects will move back and forth on both sides of the willow leaf, and each time they move, they will copy the same nucleic acid as the edge pattern of the willow leaf.

"Matching tastes" is the key. As long as the "bumps and bumps" on the "little bug" match the "bumps and bumps" of the willow leaf edge patterns, they can play the role of "primers" to guide the PCR reaction and amplify many identical sequences on the nucleic acid sequence with specific "edge patterns", thereby showing positive.

If the primer cannot find a "matching" sequence and cannot amplify, the result will be negative.

During the inactivation process of the vaccine, the virus is completely dead, but the "appearance" of the nucleic acid may not be completely destroyed. To make an inappropriate analogy, facial recognition of a dead person is likely to be a successful match.

In this regard, the Chinese Center for Disease Control and Prevention stated in the above-mentioned "Recommendations" that it is not recommended to routinely collect environmental specimens and conduct nucleic acid testing on vaccination units. If monitoring has been carried out and found to be positive, or if the viral nucleic acid test of environmental samples collected near the vaccination site is positive, it is recommended to use the whole genome sequencing of the virus to clarify whether the nucleic acid is the vaccine strain. That is, a more comprehensive sequencing method is used to further verify whether the "red light" is a true alarm.

◎ Science and Technology Daily reporter Zhang Jiaxing

Source: Science and Technology Daily

Editor: Zhang Qiqi

Review: Julie

Final judge: Leng Wensheng