中国の武漢封鎖、７０万人の感染防いだ可能性　論文が指摘

【ワシントンＡＦＰ＝時事】新型コロナウイルス感染症（COVID-19）の世界的大流行の中心地となった中国・武漢を封鎖した中国当局の決断は、ウイルスの拡散を遅らせ、70万人以上の新規感染を防いだ可能性があるとする論文が3月31日、米科学誌サイエンスに発表された。（写真は資料写真）
　中国、米国、英国の共同研究チームは、感染者数の発表や公衆衛生に関する情報、携帯電話の位置情報の履歴を使ってウイルスの拡散について調査を実施。流行の最初の５０日間に中国当局が実施した大規模な移動制限により、国内の他の都市が独自の規制を策定、施行するための貴重な時間が生まれたと指摘している。
　論文の共同執筆者で英オックスフォード大学研究員のクリストファー・ダイ氏は報道発表で、「中国の制限措置は、感染の連鎖をうまく断ち切り、感染力のある人と影響を受けやすい人の間の接触を妨げることで、功を奏したとみられる」と述べている。
　中国政府が２か月以上前に武漢の封鎖に踏み切った際には劇的な措置として受け止められたが、今や外出制限の対象は世界人口の半数近くへと拡大しており、封鎖措置は急速に常態化しつつある。
　英インペリアル・カレッジ・ロンドンの研究チームは３０日に発表した論文で、厳格な外出制限措置により欧州１１か国で合わせて最大５万９０００人の命が救われた可能性があると指摘。調査対象とした国々の大半で、外出制限によりウイルスの拡散ペースが大幅に抑制された可能性が高いと結論している。
　武漢での規制が徐々に解除され、人々の生活が少しずつ正常に戻りつつある中、中国をはじめ世界各国にとっての問いは、移動制限が解除されたらどうなるのかということだ。サイエンス誌の論文の共同執筆者、北京師範大学の田懐玉副教授（疫学）は、「居住者や国外からの感染者により再び感染が拡大する可能性を、われわれは強く認識している」と述べている。【翻訳編集ＡＦＰＢＢＮｅｗｓ】
〔ＡＦＰ＝時事〕（2020/04/03-13:38）

China's decision to lock down the city of Wuhan, ground zero for the global COVID-19 pandemic, may have prevented more than 700,000 new cases by delaying the spread of the virus, researchers said Tuesday.
Drastic Chinese control measures in the first 50 days of the epidemic bought other cities across the country valuable time to prepare and install their own restrictions, according to the paper by researchers in China, the United States and the UK, published in the journal Science.
By day 50 of the epidemic -- February 19 -- there were 30,000 confirmed cases in China, said Oxford fellow Christopher Dye, one of the paper's authors.
Our analysis suggests that without the Wuhan travel ban and the national emergency response there would have been more than 700,000 confirmed COVID-19 cases outside of Wuhan by that date, he was quoted as saying in a press release.
China's control measures appear to have worked by successfully breaking the chain of transmission -- preventing contact between infectious and susceptible people.
The researchers used a combination of case reports, public health information and mobile phone location tracking to investigate the spread of the virus.
The phone tracking provided a fascinating new stream of data, said another of the report's authors, Penn State biology professor Ottar Bjornstad.
The time period they studied encompassed two of China's biggest holidays, the Spring Festival and the Lunar New Year.
The researchers were able to compare patterns of travel into and out of Wuhan during the outbreak with cell phone data from two previous spring festivals, Bjornstad said.
The analysis revealed an extraordinary reduction in movement following the travel ban of January 23, 2020. Based on this data, we could also calculate the likely reduction in Wuhan-associated cases in other cities across China.
The Wuhan shutdown delayed the arrival of the virus in other cities, their model showed, giving them time to prepare by banning public gatherings and closing entertainment venues, among other measures.
Nearly half of humanity has now been told to stay home to curb the spread of the virus, and lockdowns are rapidly becoming normalized.
But when Beijing first shut down Wuhan more than two months ago, the decision was seen as a dramatic escalation in the fight against infection.
With the restrictions in the city slowly being lifted and life inching closer to normal, the question for China -- and other countries around the globe -- is what will happen once movement resumes.
We are acutely aware that resident or imported infections could lead to a resurgence of transmission, said another of the report's authors, Huaiyu Tian, an associate professor of epidemiology at Beijing Normal University.