Mutation makes the new coronavirus spread 10 times faster? Unreliable

Experts say there is no direct relationship and the possibility of affecting the effect of the vaccine is small

　　A few days ago, there were media reports that officials from the Ministry of Health of Malaysia claimed that the spread of the new coronavirus D614G variant strain may be 10 times faster than the general strain.

　　One stone stirred up a thousand waves. Netizens expressed concern in the comment area, and some people left a message: "The spread is 10 times faster... Don't give your children this vaccine later than October..."

　　Is it true that it spreads 10 times faster? Will the D614G mutation invalidate the vaccine that has been developed? A reporter from Science and Technology Daily contacted several experts. They said that they disagreed with the statement that "mutation makes the new crown virus spread 10 times faster."

There is no direct causal relationship between D614G mutation and 10 times faster transmission

　　The D614G mutation refers to the change from D (aspartic acid) to G (glycine) in the 614th amino acid of the new coronavirus S protein.

　　"The emergence of the D614G mutant strain is not new. Judging from the new coronavirus sequencing database we monitored, the mutation at this locus appeared very early." An expert in the field of bioinformatics data said that Malaysia as early as March The D614G mutant strain has appeared.

　　The expert said that the existing information and data cannot support the conclusion that the D614G mutation makes the spread 10 times faster. If the relevant research really concludes that the spread is 10 times faster, it will not be caused by a single factor of D614G mutation, but there are other reasons that have not been paid attention to.

　　"Some opinions are unreliable and worthy of admissibility and comment. There should be a criterion, such as whether they have published academic papers." The expert reminded that papers published by journals not only have research methods and detailed data conclusions, but also have passed peers. Review, editorial review, and more credibility.

　　A reporter from Science and Technology Daily found that the paper titled "Changes in the S Protein of New Coronavirus: Evidence of D614G Enhancement of Infectivity" used by the relevant media as corroboration clearly stated that the D614G mutation may be related to the higher viral load of patients with new coronary pneumonia , But it has nothing to do with the severity of the disease, which is rarely mentioned in media reports.

Propagation 10 times faster is unlikely

　　Spread 10 times faster, how to calculate this number?

　　Surely it is impossible to count like timing sprinter Bolt.

　　Clinical and laboratory methods are used in the above article. One is based on the patient’s viral load. There is an implicit hypothesis that the patient carries more viruses and is more infectious, which is like a sack of rice. The spread area is larger when the rice goes out and a small plastic bag of rice is scattered. The other method is to verify at the cell level, by comparing the mutant strain with the new coronavirus that broke out in Wuhan, comparing infected cells with the same virus titer How much is the number.

　　Regarding the first method, an article titled "The Significance of Variation: What the D614G mutation means for the pandemic is still unclear" published online by "Cell" stated: Although this hypothesis is reasonable, it is actually true. , Some transmission may occur in the early stage (virus cannot be detected), so high viral load may not be a direct reflection of transmission potential.

　　Regarding the second method, the article does not consider the influence of other viruses or host proteins, nor does it consider the interaction of the human as a whole with pathogens.

　　"Extending from cells to people is indeed a bit far-fetched." Li Kefeng, an associate professor at the University of California, San Diego Medical Center, told a reporter from Science and Technology Daily that it is not possible to quantify the transmission power through experiments at the cell level. "It might be more credible if you use animal experiments." Li Kefeng said that cell experiments draw conclusions quickly and everyone is eager to publish them, but the reliability of the conclusions will be greatly compromised.

　　From another perspective, this conclusion can be judged to be exaggerated: the R0 value of the new coronavirus (note: the R0 value indicates the number of people who can be infected by a patient) is about 3-4. If the spread is 10 times faster, it means that the R0 value must reach 30 —40. This is almost non-existent in infectious diseases currently recognized by humans.

The mutation does exist, and the possibility of affecting the vaccine is small

　　"Analysis of the existing more than 80,000 new coronavirus sequences shows that the number of D614G mutated virus sequences reaches about 80%." Experts in the aforementioned bioinformatics data field said that excluding some sequencing but not publicly included, it can basically be concluded This type of variation has become the dominant conclusion.

　　However, the summary of the changes in the new coronavirus should be three-dimensional and should not only focus on the speed of transmission. For example, based on the data collection and analysis of the new crown pneumonia epidemic in some countries, some researchers have concluded that the child infection rate in some countries has increased sharply, and the number of severely ill patients has decreased sharply.

　　Regarding the question of whether the D614G mutation will affect the vaccine effect, the above-mentioned experts explained that although the 614 site is on the S protein (this protein is considered to be the "key" for the virus to enter the human body), it is not in the S protein vaccine target area. It can be understood that it may be on the "key handle".

　　A protein is a three-dimensional structure, and a change in a site may also cause the adjustment of the three-dimensional structure of the protein, such as "collapse", so the effect of the mutation still needs to be followed up.

　　Relevant researchers said that if the uploaded sequence can include information such as whether the patient from which the sequence originated is dead, asymptomatic infection or mildly ill, it will help researchers obtain more useful analysis closer to the real world.

　　Our reporter Zhang Jiaxing