US CDC - vaccinated people have the same viral load of Delta strain if infected

Recently CNN.co.jp reported the following:

デルタ株、感染したらワクチン接種者でも同じウイルス量　米ＣＤＣ

2021.07.31 Sat posted at 10:26 JST

 （ＣＮＮ） 米疾病対策センター（ＣＤＣ）は３０日、新型コロナウイルスの変異株「デルタ株」に感染した場合、ワクチン接種者の体内でも未接種者とほぼ同量のウイルスを生み出すことを示す研究結果を公表した。

米連邦政府は今週、接種完了者にも屋内でのマスク着用を推奨する指針を出しており、ＣＤＣはこの判断の主な動機となったデータを公表した形だ。

専門家によると、ワクチン接種によりそもそも新型コロナに感染する可能性は低減できるものの、感染者となった場合、接種者であっても未接種者と同様にウイルスを拡散する可能性があることが示唆されている。

ＣＤＣのワレンスキー所長は声明で、「ウイルス量の多さは感染リスクの高さを示唆する。他の変異株とは異なり、デルタ株に感染したワクチン接種者はこのウイルスを他人に感染させる懸念がある」としている。

研究では、７月にマサチューセッツ州バーンスタブル郡で感染した同州の住民４６９人を分析した。この中で死者は報告されていない。

約７４％に当たる３４６人はワクチン接種を完了しており、このうち７９％が症状を訴えた。遺伝子解析の結果、デルタ株が主な要因だったことが判明した。

ウイルス量については、接種完了者１２７人とその他の８４人（未接種者や接種が完了していない人、あるいは接種状況が不明な人）の間でほぼ同様なことが判明した。ウイルス量は、他人にウイルスをうつす可能性がどの程度あるかを示す代用データとなる。

ワレンスキー氏は２７日、感染リスクが「高い」または「相当高い」地域で屋内のマスク着用を再開すべきとの指針を発表した際、こうした研究結果に言及していた。現在、米国民の７５％超がこうした地域に居住する。

ワレンスキー氏の３０日の声明によると、ＣＤＣが指針改定に踏み切った背景には、デルタ株はワクチン接種者の間でも同様のウイルス量を生み出すというこうした「重要な発見」があったという。

Translation

(CNN) The US Centers for Disease Control and Prevention (CDC) announced on the 30th a research result which showed that when infected with the new coronavirus mutant "Delta strain”, about the same amount of virus were produced in the body of vaccinated people as in the unvaccinated people.

This week, the U.S. federal government issued guidelines to encourage those who had completed vaccination to wear masks indoors. It was in a form of publishing the data that became the main motivation for CDC to make such a decision.

Experts said that vaccination could reduce the chance of getting the new corona in the first place, but if you become infected, it was suggested that even those who had been vaccinated could spread the virus same as those who had not.

CDC Director Walensky said in a statement that "the high amount of virus suggests a high risk of infection; unlike other mutant strains, there is a concern that vaccinated people infected with delta strains can infect others with this virus”.

A study was done in July to analyze 469 residents of Barnstable County, Massachusetts who all had been infected. No deaths was reported in this group.

Among them, 346 people or about 74% had completed vaccination, of which 79% had complaints of the symptoms. As a result of genetic analysis, it was found that the Delta strain was the main factor.

It was found that the viral load was almost the same between one group of 127 people who had completed vaccination and 84 other people (people who had not been vaccinated, those who had not finish vaccinated, or those whose vaccination status was unknown). The viral load served as a substitute data to indicate how likely it was that the virus could be transmitted to another person.

Walensky mentioned these findings when she released guidelines on the 27th to suggest that indoor masks should be resumed in areas where the risk of infection was "high" or "significantly high." Currently, over 75% of Americans lived in these areas.

According to Walensky 's statement on the 30th, the CDC's decision to revise the guidelines was due to the "important findings" that the Delta strain produced similar viral load among vaccinated people.

              So, according to CDC Director Walensky there is a concern that vaccinated people infected with Delta strains can also infect others. A study shows that the viral load of Delta strain is almost at the same level between two groups people, one group has completed vaccination while the other with unknown vaccination status. I think globally, people have to learn to co-live with this virus in the years to come. Apart from getting vaccinated, to wear masks, to frequently wash hands, to keep social distancing; and to stay away from poorly ventilated and overcrowded environments are the new ways of life.