SARS-CoV-2 infection: the environmental endurance of the virus can be influenced by the increase of temperature

Objectives: To evaluate whether the increase of temperature can influence the environmental endurance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Methods: Virus was inoculated on a plastic surface and harvested at predefined time-points in parallel at 20°C-25°C (room temperature; RT) and at 28°C (June temperature; JT). Samples were tested by TCID₅₀ titres on Vero cells.

Results: Our results confirm that fomite transmission of the emerging SARS-CoV-2 is possible: the virus reserved its ability to infect cells for up to 84 hours at both RT and JT on a plastic surface, with TCID₅₀ viral titres of 0.67 and 0.25 log₁₀, respectively. At RT, an important reduction in the viral titre, from 4 log₁₀ to 3 log₁₀ TCID₅₀, was observed during the first 24-36 hours. At JT, the same decay was observed more rapidly (between 8 and 12 hours), The rate of viral inactivation by D-value was 24.74 hours at RT and 12.21 hours at JT.

Conclusions: This remarkable difference between the two temperatures suggests that virus vitality can be influenced by the environmental temperature and that the hot season could reduce the probability of COVID-19 transmission.