For the first time in Japan, it was found that two people were infected with the mutant virus "Mu strain" of the new coronavirus.
Mutant virus that appears one after another.
We have summarized what types have been reported so far and what their characteristics are.
What is "Mu stock"?
WHO = World Health Organization has positioned the mutant virus "Mu strain" of the new coronavirus as "VOI = notable mutant strain" on August 30, 2021.
This time, the Greek letter "Lambda" was followed by "Mu stock".
According to WHO, Mu strains have been confirmed to be infected in South America and Europe since they were first confirmed in Colombia in South America in January 2021, and are increasing especially in Colombia and Ecuador.
According to the website "GISAID" that registers the gene sequence of the new coronavirus, it has been reported in 42 countries and regions as of September 2.
In addition, according to the website of a research institution that collects information on mutant viruses, the mu strain contains a mutation called "N501Y" in the gene of the virus "spike protein" and a mutation called "E484K" that escapes from antibody attack. These two mutations have been confirmed in South Africa and are also found in the "beta" strain, which WHO has positioned as a "VOC = Variant of Concern".
According to WHO, preliminary data reports that the immune function obtained with vaccines etc. is reduced as with the "beta strain", but further research is needed to determine the detailed properties. ..
For this reason, WHO will pay close attention to the situation of mu stocks, especially when it becomes popular at the same time as "delta stocks".
WHO = World Health Organization
▽ infection force becomes stronger
▽ infected severity is increased when was
effect falls of ▽ vaccine
a mutant virus that changes in properties such as is believed to have occurred as a "concern is a mutant strain = VOC" We are calling for international vigilance.
▽ mutant viruses that may affect infectivity and vaccine effects, and
that have been found across countries and regions are
defined as "mutant strains to be careful = VOI".
WHO advocates calling the mutant virus in Greek letters to prevent discriminatory treatment in certain countries.
As of September 2, 2021, nine types of mutant viruses are listed as "VOC" and "VOI".
4 types of "variant of concern = VOC"
There are four types of mutant viruses that WHO calls "VOC".
The "alpha strain" of the mutant virus found in the United Kingdom was first reported in early December 2020 and has since spread worldwide.
It is known that this virus has a mutation called "N501Y" in "spike protein".
This means that the 501st amino acid of "spike protein" has been replaced by tyrosine (abbreviation Y) from asparagine (abbreviation N).
According to information compiled by WHO, this mutant virus is more infectious than traditional viruses and has a higher risk of hospitalization, severe illness and death.
On the other hand, Pfizer, Moderna, and AstraZeneca vaccines do not have a significant effect on the effectiveness of the vaccine.
The first mutant virus found in South Africa is called the "beta strain".
It was alleged to have occurred in May 2020, and most analyzes performed in South Africa in mid-November suggest that it was the mutant virus.
In addition to the "N501Y" mutation, there is also a "E484K" mutation that escapes antibody attack, so there are concerns about its effect on the effectiveness of the vaccine.
According to the WHO summary, the effects of Pfizer and Moderna vaccines range from "minimal" to "significantly reduced" studies.
The mutant virus that spread in Brazil is called the "gamma strain".
It was first detected in people arriving in Japan from Brazil on January 6, 2021.
In Brazil, it was confirmed in the sample in November 2020, and according to WHO, as of March / April 2021, it was 83% of the samples whose genes were examined in detail in Brazil.
Similar to the "beta strain" confirmed in South Africa, it is known that there is a mutation of "E484K" that escapes antibody attack in addition to "N501Y".
According to the WHO summary, Pfizer, Moderna, and AstraZeneca vaccines have been reported to have "low" to "moderate" effects.
Of the three types of mutant viruses found in India that contain the mutation "L452R", the type with the most widespread infection is called the "delta strain" and is called VOC.
It is said that the infectivity is increasing, and it has been pointed out that the risk of hospitalization may increase if infected.
Regarding the effectiveness of the vaccine, the WHO summary shows that Pfizer's vaccine had little or no effect on the effect of neutralizing the virus.
5 types of "Mutant strains to be careful = VOI"
There are five types of mutant viruses that WHO positions as "VOI", including "Mu strain".
▽ "Eta strain" This
is the first mutant virus confirmed in the United Kingdom in December 2020.
▽ "Iota strain" It
is a mutant virus found in New York, USA.
▽ "Kappa strain"
A mutant virus found in India has a mutation of "L452R" as well as "Delta strain".
▽ "Lambda strain" This
is the first mutant virus reported in Peru, and according to WHO, it has been reported from 29 countries and regions as of June 15, 2021, especially in South America such as Peru and Chile. It means that there is.
It means that the infectivity and the effect on the effect of the vaccine are not well understood yet.
Other mutant viruses
Each country independently decides a mutant virus that becomes "VOC" or "VOI" according to the actual situation in each region.
In Japan as well, the National Institute of Infectious Diseases has designated all four types of mutant viruses that are WHO "VOCs" as "VOCs" as of September 2, 2021 and also designated "Kappa strains" as "VOIs". It is specified.
All are believed to have come from overseas, but the detailed origin is unknown and it is believed that their infectivity remains unchanged.
In addition, although it is unlikely that these mutant viruses will completely nullify the effect of the vaccine, it is necessary to pay close attention to the infection situation considering the possibility of reducing the effect.
In the world, the gene sequences of the new coronavirus are published in the database, and new mutant viruses are being reported one after another.
WHO wants each country to continue to strengthen its countermeasures through investigations to see the spread of the virus, strategic tests, and genome analysis.Keywords: