"1.78 times" of the conventional new coronavirus.
This is the analysis result of the domestic infectivity of the most widespread "Delta strain" among the mutant viruses of the new coronavirus confirmed in India.
Experts caution that "future measures need to assume high infectivity (of Delta strains)."
In 74 countries / regions around the world
On the 31st of last month, the WHO = World Health Organization encouraged governments and others to use Greek alphabetic designations for major mutant viruses to prevent discriminatory treatment of certain countries.
According to it,
▼ the first confirmed mutant virus in the United Kingdom was "alpha",
▼ the one confirmed in South Africa was "beta",
▼ the one spread in Brazil was "gamma",
and
▼ the one confirmed in India. , The most expanding one is "Delta".
According to WHO, the number of countries and regions where the mutant virus "Delta strain" confirmed in India was reported was 74 as of the 8th of this month, an increase of 12 from the previous week.
In addition, according to the Ministry of Health, Labor and Welfare, it was reported that in Japan, a total of 34 people were infected with the mutant virus confirmed in India from 8 prefectures in the week until the 7th of this month.
It is 10 more than the number confirmed in the previous week.
Tokyo inspection "Delta stock" more than 30%
On the other hand, in the screening test conducted by a research institute in Tokyo during the week leading up to the 6th of this month, the mutant virus "Delta strain" confirmed in India accounted for more than 30%, the highest number ever.
The Tokyo Metropolitan Institute of Health and Safety has analyzed a total of 38 samples in a screening test that examines samples extracted from some of the newly positive individuals in the week leading up to the 6th of this month.
As a result, the mutant virus "Delta strain" confirmed in India was detected in 12 cases, which is 31.6%.
Eleven of the twelve are clusters that have occurred in junior high school, which have been confirmed since the 8th.
Infections in junior high school students and their families have been confirmed one after another.
In addition, 19 cases, which is 50%, were detected by the mutant virus "Alpha strain" found in the United Kingdom, and the remaining 7 cases were detected by the conventional virus.
Mitsuo Kaku, a specially appointed professor at Tohoku Medical and Pharmaceutical University, who chairs the "Expert Board" in Tokyo, said that "Delta stock" accounted for more than 30%. It cannot be judged from this number alone that it has spread throughout the city. However, since "Delta strain" is 1.5 times more infectious than "Alpha strain", it is highly possible that it will be replaced in the future. I was talking.
In addition, the city has announced that it will switch the screening test that was checking whether it is an "alpha strain" to a "delta strain", saying that the virus in Tokyo has almost replaced the "alpha strain".
Infectivity is 1.78 times that of conventional viruses
What is the infectivity of this mutant virus?
The results of an analysis conducted by a group of Professor Kojin Ito of Hokkaido University and Professor Hiroshi Nishiura of Kyoto University were presented at an expert meeting of the Ministry of Health, Labor and Welfare on the 9th.
The group uses an international database of new coronaviruses to analyze changes in the number of mutant viruses registered from within Japan.
As a result, it was found that the infectivity of the mutant virus "Delta strain" confirmed in India in Japan may be "1.78 times" that of the conventional virus.
In addition, although it is a trial calculation from the data so far, it is predicted that the proportion of this mutant virus in the total new coronavirus in Japan will exceed half of the total by the middle of next month.
Professor Nishiura said, "It is necessary to update the analysis with the latest information, but the high infectivity of" Delta strain "has been found from the data in Japan. We need to make assumptions. "
“The medical system is tight at once”
At the Tokyo Metropolitan Medical Association's monitoring meeting held on the 10th, Vice Chairman Masataka Inoguchi of the Tokyo Metropolitan Medical Association said, "When the infection of'Delta strain' spreads, the medical care provision system will be tightened at once. I have been driven out and I really have no spare capacity. I would like to ask for your cooperation so as not to spread the infection. "
Does the vaccine work?
Although the WHO reports are still limited on the effectiveness of the vaccine against this mutant virus,
▼ the effect of reducing the effect of preventing the onset
is "almost nonexistent" with
the
Pfizer vaccine and the AstraZeneca vaccine, and
▼ The amount of neutralizing antibody that suppresses the action of the virus is also
said to be sufficient, although it decreases to some extent with
the
Pfizer vaccine and the Modelna vaccine.
Of these, according to a report issued by the British government on May 22, 2021 regarding the effect of preventing the onset,
93% of
the mutant virus "alpha strain" confirmed in
the
United Kingdom was
vaccinated twice with Pfizer's vaccine. ,
▽ the vaccine of AstraZeneca 66 percent in after inoculated twice
against was the,
for confirmed mutant virus "delta strain" in India,
▽ Pfizer's vaccine 88 Pasento
▽ AstraZeneca of vaccine Is 60%, and
"two inoculations are sufficient".