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New mutant viruses are reported one after another in the world. We have summarized the prevalence and characteristics of the mu strain from Colombia and the lambda strain from Peru, which are currently attracting attention.

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Global situation of new coronavirus infectious disease-Situation of mutant strains

The World Health Organization (WHO) has identified three variants of the new coronavirus in order of risk: ``Variants of Concern (VOC)'', ``Variants of Interest (VOI)'', and ``Mutants to Continue Surveillance''. are classified into The four most dangerous VOCs are the delta strain from India, which is currently prevalent in the world, the alpha strain from the UK, the beta strain from South Africa, and the gamma strain from Brazil. Five types of VOI are designated, including mu strains and lambda strains. Furthermore, 12 types of mutant strains have been designated to continue monitoring (as of September 2nd).

The mu strain was designated as a VOI by WHO on August 30, 2018. In January 2021, it was first found in Colombia, South America, and the infection has been confirmed in Europe. According to WHO, the prevalence of mu strains was less than 0.1% globally at the end of August, but is rising to 39% in Colombia and 13% in Ecuador. As of September 13, it has been reported in 48 countries including Japan. In Japan, mu strain was detected in two people who entered Japan in June and July this year.

The mu strain has 21 mutations, including the 'N501Y' and 'E484K' mutations in the spike protein gene, which is the protruding part of the virus. Both the N501Y and E484K mutations are mutations carried by beta and gamma strains. It has been pointed out that mutants with the N501Y mutation are more infectious than conventional strains, and mutants with the E484K mutation may reduce the effects of immunity and vaccines more than conventional strains. In addition, a mutation of P681H has also been confirmed, and it is thought that it may be easier to infect than the conventional strain.

When a research team such as the Institute of Medical Science of the University of Tokyo examined the effect of antibodies against mutant strains using the blood of Pfizer vaccine recipients and those infected with conventional strains, it was found that against mu strains, vaccine recipients The antibody effect was reduced to 1/7 or less than the conventional strain.

On the other hand, the lambda strain was found in Japan from an Olympic official who had a history of staying in Peru in July this year. It was first reported in Peru in South America in August 2020, and has spread to about 30 countries around the world, mainly in South America. WHO designated this variant as a VOI in June this year. In South America, more than 20% of new Covid-19 infections are now attributed to the Lambda strain.

The lambda strain has mutations such as ``F490S'' and ``L452Q'' in the spike protein gene, and it has been pointed out that the virus may be more infectious than conventional strains, alpha strains, and gamma strains. Studies have also shown that mRNA vaccines can attenuate the effects of neutralizing antibodies produced in the body.

There is a risk that new mutated strains of the new corona will emerge in the future, but the appearance of mu and lambda strains may increase the infectivity of the new corona or reduce the effectiveness of vaccines. You can say that it is a close-up of something.