Omicron Infections Are Contagious for at Least 6 Days

By Reuters Staff

March 18, 2022

(Reuters) - Patients infected with the Omicron variant of SARS-CoV-2 remain contagious for just as long as patients infected with earlier variants, according to a small study.

Researchers took blood samples from 56 newly diagnosed patients, including 37 with Delta infections and 19 with Omicron infections. All were mildly ill, such as with flu-like symptoms, but none were hospitalized. Regardless of which variant or whether or not they had been vaccinated or boosted, study participants "shed live virus for, on average, about 6 days after symptoms (began), and... about one in four people shed live virus for over 8 days," said Dr. Amy Barczak of the Massachusetts General Hospital in Boston, who coauthored a report posted on medRxiv ahead of peer review.

"Although it is unknown exactly how much live virus is needed to spread the disease to others, we take these data to suggest that people with mild COVID-19 infection may be contagious on average for 6 days, and sometimes longer," Barczak said. "Decisions about isolation and masking should take such information into account, regardless of variant or prior vaccination status."

SOURCE: medRxiv, online March 2, 2022.