A new type of mutated coronavirus "E484K" that is different from the one that spread in England and South Africa.

This type has been pointed out as having the potential to reduce the effects of immunity and vaccines.



A research group at Tokyo Medical and Dental University Hospital, which was detected in one-third of the confirmed cases of infection, said that the mutant virus may have replaced the conventional virus in Tokyo.

What is the "E484K" mutation?

"E484K" is one of the mutations of the new coronavirus and means that the 484th amino acid of the "spike protein" amino acid has changed.



It is thought that this mutation has the property of escaping the attack of antibodies, and it has been pointed out that it may be easier to re-infect and the vaccine may be less effective.



It is known that the mutant virus confirmed in South Africa and the mutant virus spread in Brazil have this mutation in addition to the mutation called "N501Y" which is said to enhance infectivity.



This time, it is a mutant virus that does not have "N501Y" but has "E484K".



According to the National Institute of Infectious Diseases, two cases of the same virus were found in the quarantine at the airport by the 3rd of last month, and 394 cases were found in Japan. Reported that there were cases in which it appeared to have mutated in Japan.



The nature of this mutant virus is not yet known in detail, but so far no changes have been reported, such as markedly increased infectivity or increased symptoms.



In addition, the screening of mutant strains currently conducted in local governments nationwide finds mutations in "N501Y", and in order to find "E484K", it is necessary to analyze the genetic information in detail.



The National Institute of Infectious Diseases will continue to analyze and monitor the genetic information of this mutant virus to understand the actual situation.

What is "E484K"?

The mutation called "E484K" means that the 484th amino acid of "spike protein" has been replaced from glutamic acid (abbreviation E) to lysine (abbreviation K).

What is "N501Y"?

The mutation called "N501Y" means that the 501st amino acid of "spike protein" has been replaced from asparagine (abbreviation N) to tyrosine (abbreviation Y).

Mutant viruses are categorized in detail according to which part of the genetic information the mutation occurs in.



Of these, the WHO = World Health Organization currently lists the following three types as "mutant strains of concern = VOCs".

Mutant virus found in the United Kingdom

It is a mutant virus that was found in the United Kingdom last December and has since spread around the world.



It is the most frequently reported mutant virus in Japan and is officially named "VOC-202012 / 01".



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 from asparagine (abbreviation N) to tyrosine (abbreviation Y).



According to the WHO summary, the infectivity is 36% to 75% higher than that of conventional viruses, and if infected, there is a possibility that there is an increased risk of hospitalization, serious illness, and death.

Mutant virus spread in Brazil

The other is a mutant virus found in South Africa.



It is officially called "501Y.V2".



This mutant virus has the same "N501Y" mutation as the mutant virus found in the United Kingdom.



Furthermore, it is known that a mutation called "E484K" is also occurring.



This means that the 484th amino acid of "spike protein" has been replaced from glutamic acid (abbreviation E) to lysine (abbreviation K).



According to the WHO summary, South Africa reports that the infectivity is 50% higher and the hospital mortality rate is 20% higher than the conventional virus.

Mutant virus spread in Brazil

And the other is a mutant virus that has spread in Brazil.



It was first found in airport quarantine for people from Brazil to Japan.



This is the same mutation virus found in South Africa, with both "N501Y" and "E484K" mutations.



According to the WHO summary, it seems to be more infectious than conventional viruses, but the severity of infection is being investigated, but the impact is limited.