Table 3. Titer calculation for HCoV-229E, HCoV-NL63, and HCoV-OC43.

Virus	Plaque assay titration results	Plaque counting	Viral titer (PFU/mL)
HCoV-229E	Figure 6A	10-4 well: 12	(12×104/0.5+80×103/0.5)/2=2×105
		10-3 well: 80
HCoV-NL63	Figure 7A	10-6 well: 4	(4×106/0.5+32×105/0.5)/2=7.2×106
		10-5 well: 32
HCoV-OC43	Figure 8A	10-5 well: 8	(8×105/0.5+58×104/0.5)/2=1.38×106
		10-4 well: 58