「発症２日前」「１メートル内」「１５分以上」　濃厚接触者の定義変更―感染研

　国立感染症研究所は２１日までに、新型コロナウイルス患者の濃厚接触者の定義を変更した。患者への接触時期について、従来は「発症日以降」だったが「発症２日前」に早めた。一方、患者との距離については「手で触れる、または対面で会話することが可能な距離（目安２メートル）」を「手で触れることのできる距離（目安１メートル）」と短くした。
　これまで明示してこなかった患者との接触時間については、「（マスクなどの）必要な感染予防策なしで１５分以上の接触があった者」と定めた。
　各地の保健所が濃厚接触者を追跡調査する際の基準とする「積極的疫学調査実施要領」を２０日付で改定し、ホームページで公開。その中で、定義変更を明らかにした。海外の最新知見を基にしたとみられ、感染研が発症２日前から感染の危険性があることを公に認めた格好だ。（2020/04/21-15:28）

Japan's National Institute of Infectious Diseases has changed the definition of people who had close contact with patients of the COVID-19 disease, caused by the novel coronavirus.
   According to the new definition, people who were at a distance of one meter, enough to touch by hand, from an infected person for 15 minutes or more without taking infection prevention measures, such as wearing a face mask, two days before the person started to display symptoms or later are regarded as those with close contact with the patient.
   The institute had previously defined people who were at a distance of 2 meters, enough to touch by hand or talk face to face, from a COVID-19 patient on the day he or she began to show symptoms or later as those with close contact. The old definition did not include a duration of contact.
   On Monday, the institute released on its website revised guidelines used by public health centers for tracking down people who had close contact with infected people. The new definition, apparently based on the up-to-the-minute data and knowledge from abroad, is included in the revised guidelines.
   On Tuesday, the health ministry issued a notification calling on local governments to advance their activities to track and identify people who had close contact with COVID-19 patients using the new definition.