Table 2.
Stability of SARS‐CoV‐2 on the surface of materials at 4℃ or room temperature (RT, 22℃).
| Materials | Assay | Survived virus on the surface of the materials for days* | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 2 h** | Day 1 | Day 3 | Day 5 | Day 7 | Day 9 | Day 12 | Day 14 | ||
| Stainless steel at 4℃ | CPE*** | / | ++++ | ++++ | ++++ | ++++ | +++ | ‐ | ‐ |
|
logTCID50 **** percentage (%) |
/ | 3.50 ± 0.25 (31.62) | 3.08 ± 0.29 (12.02) | 2.83 ± 0.14 (6.76) | 2.58 ± 0.14 (3.80) | 1.50 ± 0.37 (0.32) | UD | UD | |
| Stainless steel at RT | CPE | ++++ | ++++ | ++++ | ‐ | ‐ | / | / | ‐ |
|
logTCID50 percentage (%) |
4.00 ± 0.38 | 2.25 ± 0.25 (1.78) | 1.33 ± 0.14 (0.21) | UD | UD | / | / | UD | |
| Plastic bag at 4℃ | CPE | / | ++++ | ++++ | ++++ | ++++ | ++++ | +++ | ‐ |
|
logTCID50 percentage (%) |
/ | 3.25 ± 0.43 (21.38) | 3.58 ± 0.14 (45.71) | 2.83 ± 0.38 (8.13) | 2.25 ± 0.43 (2.14) | 2.51 ± 0.29 (3.89) | 1.75 ± 0.57 (0.68) | UD | |
| Plastic bag at RT | CPE | ++++ | ++++ | ++++ | ‐ | ‐ | / | / | ‐ |
|
logTCID50 percentage (%) |
3.92 ± 0.38 | 2.50 ± 0.50 (3.80) | 2.00 ± 0.50 (1.20) | UD | UD | / | / | UD | |
| Nonwoven fabric at 4℃ | CPE | / | ++++ | ++++ | ++++ | ++ | ++ | ‐ | ‐ |
|
logTCID50 percentage (%) |
/ | 3.08 ± 0.58 (177.82) | 2.42 ± 0.58 (38.90) | 2.08 ± 0.58 (17.78) | 0.58 ± 1.01 (0.56) | 0.52 ± 0.47 (0.50) | UD | UD | |
| Nonwoven fabric at RT | CPE | ++++ | ++++ | ‐ | ‐ | ‐ | / | / | ‐ |
|
logTCID50 percentage (%) |
2.83 ± 1.13 | 1.08 ± 0.95 (1.77) | UD | UD | UD | / | / | UD | |
| Rubber gloves at 4℃ | CPE | / | ++ | ‐ | / | / | / | / | / |
|
logTCID50 percentage (%) |
/ | 0.33 ± 0.47 (12.02) | UD | / | / | / | / | / | |
| Rubber gloves at RT | CPE | ++++ | ‐ | ‐ | / | / | / | / | / |
|
logTCID50 percentage (%) |
1.25 ± 2.16 | UD | UD | / | / | / | / | / | |
Abbreviations: CPE, cytopathic effects; SARS‐CoV‐2, severe acute respiratory syndrome coronavirus 2.
The nCoV‐SH01 (4.00 log10 TCID50) in 10 µl DMEM was added on the surface of each material and placed on the biosafety cabinet to dry naturally for 30 min at 22℃. The eluting virus was detected by CPE and TCID50 at Day 1, 3, 5, 7, 9, 12, or 14. The experiments were carried out in triplicate wells for each dilution.
The virus was naturally dried at room temperature for 2 h. Then the eluted virus activity and titer were measured to calculate the elution efficiency (stainless steel: 100%, plastic bag: 83.18%, nonwoven fabric: 6.76%, rubber gloves: 0.18%).
CPE of Vero E6 cells was checked under a microscope at 48 h post infected. Degree of CPE, “++++”, >75% of cells; “+++”, 50%–75%; “++”, 25%–50%; “+”, 0–25%; “±”, not clear‐cut; “‐”, no CPE. The cytopathic effects were observed under a microscope daily for 5 days.
The titer of virus were determined for log TCID50 presented as mean ± SD, and percentage (%): viral survival rate in percentages = 10(viral titer at days)/10(viral titer at 2 h). UD: under detective level./: not done.