Omicron strain "XBB.1.5" tends to be highly infectious in the US - WHO initial survey

Recently NHK News on-line reported the following:

オミクロン株「XBB.1.5」 米では感染力が強い傾向 WHO初期調査

2023年1月12日 18時06分

 WHO＝世界保健機関は11日、アメリカで急速に感染が広がっている新型コロナウイルスのオミクロン株の1つ「XBB.1.5」の特徴やリスクについて、専門家による初期調査の結果を公表しました。

それによりますと、アメリカでは比較的、感染力が強い傾向が見られたほか、過去の感染やワクチン接種で得た免疫から逃れる性質もこれまでの変異株の中で、最も強い部類に入るとみられるということです。

一方で、重症化のしやすさや、現在のワクチンによって重症化や死亡率を下げる効果については、現時点では十分なデータはないということです。

こうしたことから、「XBB.1.5」について「世界的な感染者数の拡大につながる可能性があるが、感染力の強さの推定はアメリカ1か国のみのデータに基づいているため、全体的な信頼度は低い」としていて、今後もデータの収集を続け、評価を行うことにしています。

CDC＝アメリカ疾病対策センターによりますと、アメリカで今月7日までの1週間に新型コロナに新たに感染した人のうち、推計で27.6％が「XBB.1.5」で、先月3日の時点の推計2.3％から急速に広がっています。

WHOによりますと「XBB.1.5」は、去年10月22日から今月11日までの間にこれまで38か国から報告されていて、その8割以上がアメリカからだということです。

「XBB.1.5」日本国内の状況は

オミクロン株の1つ「XBB.1.5」は、複数のタイプの新型コロナウイルスが組み合わさった変異ウイルスです。

去年春ごろから日本国内でも広がったオミクロン株の「BA.2」の2つのタイプが組み合わさった変異ウイルス「XBB」に、さらに変異が加わっています。

12日に開かれた東京都のモニタリング会議では、先月1日に初めて都内で確認されて以降、これまでに15例確認されていると報告されました。

厚生労働省の専門家会合は、WHO＝世界保健機関などで感染者数の増加につながっている可能性が指摘されているものの、感染性や重症度に関する疫学や臨床の知見はないとしていて、諸外国の状況などを分析するとともに、ゲノム解析による監視を続けることが必要だとしています。

「XBB.1.5」について東京医科大学の濱田篤郎特任教授は「免疫から逃れる性質だけでなく感染力がさらに強まっている可能性が指摘されている。このウイルスの流入で今の第8波が長引くことも懸念される」と話しています。

Translation

WHO = The World Health Organization announced on the 11th the results of an initial survey by experts on the characteristics and risks of `` XBB.1.5 '', one of the Omicron strains of the new coronavirus, that is rapidly spreading in the United States.

According to this survey, in the United States, in addition to the tendency to be relatively infectious, the ability to escape immunity obtained from past infections and vaccinations were considered to be among the strongest category of the mutation strains so far.

On the other hand, there was not enough data at this time on the susceptibility to severe disease, and the effectiveness of current vaccines in reducing severe disease and mortality.

For these reasons, about "XBB.1.5", as “it may lead to an increase in the number of infected people worldwide, but the estimation of its strength of infection is based on data from only one country, the United States”, so collecting data and conducting evaluations would continue.

According to the CDC = U.S. Centers for Disease Control and Prevention, an estimated 27.6% of the people newly infected with the new corona in the United States in the week ending on the 7th of this month were "XBB.1.5", and because as of the 3rd of last month the estimate was 2.3. %, so, it was spreading rapidly.

According to the WHO, "XBB.1.5" had been reported from 38 countries between October 22nd and 11th of this year, more than 80% of which were from the United States.

The situation of "XBB.1.5" in Japan

One of the Omicron strains, “XBB.1.5,” was a mutated virus that combined multiple types of new coronaviruses.

Further mutations had been added to the mutated virus "XBB", which was a combination of two types of the Omicron strain "BA.2" that was spreading in Japan since last spring.

At a monitoring meeting held in Tokyo on the 12th, it was reported that since the first confirmation in Tokyo on the 1st of last month, 15 cases had been confirmed so far.

An expert meeting of the Ministry of Health, Labor and Welfare, it noted that although the WHO = World Health Organization had pointed out that it might lead to an increase in the number of infected people, there was no epidemiological or clinical knowledge regarding infectivity and severity, so it was necessary to analyze the situation in other countries and continue monitoring through genome analysis.

Regarding "XBB.1.5", Atsuro Hamada (濱田篤郎), a specially appointed professor at Tokyo Medical University, said, "It has been pointed out that there is a possibility that not only the nature of escaping immunity, but also the ability to infect is further enhanced. There are concerns that the current 8th wave will be prolonged due to the arrival of this virus.”

              So, WHO has announced the results of an initial survey on the characteristics and risks of XBB.1.5 that is rapidly spreading in the United States. In Japan there are concerns that its current 8th wave of coronavirus pandemic will be prolonged due to the influx of this virus. It seems that the pandemic is far from over globally.