This paper has more information: https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6909e1-H.pdf https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6909e1-H.pdf TLDR: "S

This paper has more information: https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6909e1-H.pdf https://www.cdc.gov/mmwr/volumes/69/wr/pdfs/mm6909e1-H.pdf TLDR: "Since February 28, an increasing number of newly diagnosed confirmed and presumptive COVID-19 cases have been in patients with neither a relevant travel history nor clear epidemiologic links to other confirmed COVID-19 patients. However, despite intensive follow-up, no sustained person-to-person transmission of symptomatic SARS-CoV-2 was observed in the United States among the close contacts of the first 10 persons with diagnosed travel-related COVID-19." They tracked the first 10 people in the US with travel-related confirmed COVID-19, and followed up with 445 people who had close contact with them. Over 14 days, 54 of those 445 people developed new or worsening symptoms and were tested for COVID-19. Of the 54 people, only 2 tested positive for COVID-19. Both were household members of originally infected people. "Both persons with confirmed secondary transmission had close contact with the respective source patient before COVID-19 was confirmed and were isolated from the source patient after the patient’s COVID-19 diagnosis." "No other close contacts who were tested for SARS-CoV-2 had a positive test, including the five household members who were continuously exposed during the period of isolation of their household member with confirmed COVID-19. An additional 146 persons exposed to the two patients with secondary COVID-19 transmission underwent 14 days of active monitoring. Among these, 18 (12%) developed symptoms compatible with COVID-19 and were considered PUIs. All tested negative, and no further symptomatic COVID-19 cases (representing tertiary transmission) have been identified."