Figure 1. Viral Load and Plaque-Forming Units of SARS-CoV-2 Infection by Virus Lineage, Vaccination Status, and COVID-19 Characteristics.

Viral load was measured by quantitative reverse transcriptase–polymerase chain reaction assay to assess viral shedding. Plaque-forming units were quantified on Vero cells ectopically expressing transmembrane serine protease 3 and human angiotensin converting enzyme 2 to assess virus viability.

^aMean difference and 95% CIs were estimated using linear regression controlling for time from index to swab collection, number of daily medications reported, and race/ethnicity. Hours of missed work is additionally adjusted for occupation.