- Hilt, Evann E;
- Boocock, James;
- Trejo, Marisol;
- Le, Catherine Q;
- Guo, Longhua;
- Zhang, Yi;
- Sathe, Laila;
- Arboleda, Valerie A;
- Yin, Yi;
- Bloom, Joshua S;
- Wang, Pin-Chieh;
- Elmore, Joann G;
- Kruglyak, Leonid;
- Shrestha, Lasata;
- Bakhash, Shah A Mohamed;
- Lin, Michelle;
- Xie, Hong;
- Huang, Meei-Li;
- Roychoudhury, Pavitra;
- Greninger, Alexander;
- Chandrasekaran, Sukantha;
- Yang, Shangxin;
- Garner, Omai B
Background
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused one of the worst pandemics in recent history. Few reports have revealed that SARS-CoV-2 was spreading in the United States as early as the end of January. In this study, we aimed to determine if SARS-CoV-2 had been circulating in the Los Angeles (LA) area at a time when access to diagnostic testing for coronavirus disease 2019 (COVID-19) was severely limited.Methods
We used a pooling strategy to look for SARS-CoV-2 in remnant respiratory samples submitted for regular respiratory pathogen testing from symptomatic patients from November 2019 to early March 2020. We then performed sequencing on the positive samples.Results
We detected SARS-CoV-2 in 7 specimens from 6 patients, dating back to mid-January. The earliest positive patient, with a sample collected on January 13, 2020 had no relevant travel history but did have a sibling with similar symptoms. Sequencing of these SARS-CoV-2 genomes revealed that the virus was introduced into the LA area from both domestic and international sources as early as January.Conclusions
We present strong evidence of community spread of SARS-CoV-2 in the LA area well before widespread diagnostic testing was being performed in early 2020. These genomic data demonstrate that SARS-CoV-2 was being introduced into Los Angeles County from both international and domestic sources in January 2020.