Characteristics and Timing of Initial Virus Shedding in Severe Acute Respiratory Syndrome Coronavirus 2, Utah, USA

Lewis, Nathaniel M.; Duca, Lindsey M.; Marcenac, Perrine; Dietrich, Elizabeth A.; Gregory, Christopher J.; Fields, Victoria L.; Banks, Michelle M.; Rispens, Jared R.; Hall, Aron; Harcourt, Jennifer L.; Tamin, Azaibi; Willardson, Sarah; Kiphibane, Tair; Christensen, Kimberly; Dunn, Angela C.; Tate, Jacqueline E.; Nabity, Scott; Matanock, Almea M.; Kirking, Hannah L.

Virus shedding in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can occur before onset of symptoms; less is known about symptom progression or infectiousness associated with initiation of viral shedding. We investigated household transmission in 5 households with daily specimen collection for 5 consecutive days starting a median of 4 days after symptom onset in index patients. Seven contacts across 2 households implementing no precautionary measures were infected. Of these 7, 2 tested positive for SARS-CoV-2 by reverse transcription PCR on day 3 of 5. Both had mild, nonspecific symptoms for 1–3 days preceding the first positive test. SARS-CoV-2 was cultured from the fourth-day specimen in 1 patient and from the fourth- and fifth-day specimens in the other. We also describe infection control measures taken in the households that had no transmission. Persons exposed to SARS-CoV-2 should self-isolate, including from household contacts, wear a mask, practice hand hygiene, and seek testing promptly.