Cross-sectional assessment of SARS-CoV-2 viral load by symptom status in Massachusetts congregate living facilities

ABSTRACT

Transmission of COVID-19 from people without symptoms confounds societal mitigation strategies. From April to June 2020, we tested nasopharyngeal swabs by RT-qPCR from 15,514 staff and 16,966 residents of nursing homes and assisted living facilities in Massachusetts. Cycle threshold (Ct) distributions were very similar between populations with (N = 739) and without (N = 2179) symptoms at the time of sampling (mean Ct 25.7 versus 26.4, ranges 12-38). However, as local cases waned, those without symptoms shifted towards higher Ct. With such similar viral load distributions, existing testing modalities should perform comparably regardless of symptoms, contingent upon time since infection.