Rollup of coronavirus contact tracing studies


Looked at setting of infection (household, hospital, public transit, workplace) and type of carrier (asymptomatic, mild, moderate, severe). It found that 10% of household contacts go the virus, compared to around ~0.1-1% for the other settings (hospital, public transit, workplace). The most infectious cases were "severe" severity, infecting 6% of contacts. Asymptomatic cases infected 1 out of 305 contacts. 391 cases, with 3140 contacts. China.


Looked at ages and househould vs. non-household transmission in S Korea. It found that about 11% of household contacts get the virus, and about 2% of non-household contacts get the virus. Older contacts are somewhat more likely to get the virus. Results are for 5,706 positive cases, and 59,073 contacts.


Looked at 2,812 cases with 6,690 community contacts. About 13% of the contacts developed symptoms. They found similar infection rates between workplace contacts, family/friends, and household (~10-15%). Italy.

tl;dr: study (1) shows low asymptomatic transmission, studies (1) and (2) show ~5-10x higher transmission rate within household vs. non-household, (3) shows similar transmission rate in household and work.