Fig. 2.

Determination of viral shedding by measurements of viral loads and viral titers in nasal, pharynx, and rectal swab samples. After inoculation of SARS-CoV-2, nasal (A and D), pharynx (B and E), and rectal (C and F) swab samples were collected at the indicated time points. Viral loads were determined by RT-PCR using RNA extracted from swab samples (A–C; blue: young, red: elderly). The average viral loads in the groups with the same inoculate doses are indicated by gray lines. Infectious viral titers in swab samples were determined by TCID₅₀ using VeroE6/TMPRSS2 cells (D–F; blue: young, red: elderly).