The Effect of Large-Scale Anti-Contagion Policies on the Coronavirus (COVID-19) Pandemic

Solomon Hsiang; Daniel Allen; Sebastien Annan-Phan; Kendon Bell; Ian Bolliger; Trinetta Chong; Hannah Druckenmiller; Andrew Hultgren; Luna Yue Huang; Emma Krasovich; Peiley Lau; Jaecheol Lee; Esther Rolf; Jeanette Tseng; Tiffany Wu

The second testing regime change occurred on February 4, 2020, when the KCDC announced that people who had had any "routine contacts" with confirmed cases were required to self quarantine for a 14-day period. The agency defines two categories of contacts: close contacts and routine contacts. The former is defined as a person who has been within two meters of, in the same room as, or exposed to any respiratory secretions of an infected individual. The latter refers to whether the individual conducted any activity in the same place and time as the infected person. Prior to this regime change, KCDC separated those two cases and applied different quarantine policies; starting February 4, 2020, any routine contacts were also required to be self-quarantined. 43 Shortly thereafter, South Korea aggressively expanded the scope of their testing. Starting February 7, 2020, the KCDC broadened the definition of suspected cases to 1) anyone who developed a fever or respiratory symptoms within 14 days after returning from China, 2) anyone who developed a fever or respiratory symptoms within 14 days after being in close contact with a confirmed case, and 3) anyone suspected of contracting COVID-19 based on their travel history to affected countries and their clinical symptoms. Moreover,the KCDC announced that the test would be free for all suspected cases and 44 40 https://www.cdc.go.kr/board/board.es?mid=a20501000000&bid=0015&list_no=365654&act=view 41 https://www.cdc.go.kr/board/board.es?mid=a20501000000&bid=0015&list_no=365874&act=view 42 NB: The KCDC English website explains the testing regime change in a more condensed format: "Any citizens identified with a fever or respiratory symptoms and have visited Wuhan will be isolated and tested at a nationally designated isolation hospital, and any foreigners staying in Korea will be conducted in cooperation with police." https://www.cdc.go.kr/board/board.es?mid=a30402000000&bid=0030&act=view&list_no=365888&tag=&n Page=1 43 http://www.mohw.go.kr/react/al/sal0301vw.jsp?PAR_MENU_ID=04&MENU_ID=0403&page=1&CONT_S EQ=352662 44 https://www.cdc.go.kr/board/board.es?mid=a30402000000&bid=0030&act=view&list_no=366114&tag=&n Page=1 NB: The date of this press release is February 8, 2020, but the definition of "suspected cases" was effective starting from February 7, 2020.