a For samples with multiple viruses detected, the virus with highest concentration is listed, as indicated by real-time PCR Ct value.
b Directly quantified or spiked in human negative-testing sputum.
c 1 × 105 RNA copies/mL, determined by specific real-time RT-PCR. Isolated from human airway epithelial culture.
d 1 × 1010 RNA copies/mL, determined by specific real-time RT-PCR of one isolate. The other isolate was not quantified but spiked in human negative-testing sputum.
e 4 × 109 RNA copies/mL, determined by specific real-time RT-PCR.
f 3 × 109 RNA copies/mL, determined by specific real-time RT-PCR of one isolate. The other isolate was not quantified spiked in human negative-testing sputum.
g 1 × 108 RNA copies/mL, determined by specific real-time RT-PCR.