Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1

A novel human coronavirus, now named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, referred to as HCoV-19 here) that emerged in Wuhan, China in late 2019 is now causing a pandemic1. Here, we analyze the aerosol and surface stability of HCoV-19 and compare it with SARS-CoV-1, the most closely related human coronavirus.2 We evaluated the stability of HCoV-19 and SARS-CoV-1 in aerosols and on different surfaces and estimated their decay rates using a Bayesian regression model (see Supplementary Appendix). All experimental measurements are reported as mean across 3 replicates.

This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi. org/10.1101org/10. /2020 Abstract 32  has caused >88,000 reported illnesses with a current case-fatality ratio of ~2%. Here, 33 we investigate the stability of viable HCoV-19 on surfaces and in aerosols in comparison with SARS-34 CoV-1. Overall, stability is very similar between HCoV-19 and SARS-CoV-1. We found that viable virus This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available author/funder, who has granted medRxiv a license to display the preprint in perpetuity.  This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

96
HCoV-19 remained viable in aerosols throughout the duration of our experiment (180 minutes) 97 with a reduction in infectious titer 3 hours post-aerosolization from 10 3.5 to 10 2.7 CID 50 /L (mean across 98 three replicates). This reduction in viable virus titer is relatively similar to the reduction observed in 99 aerosols containing SARS-CoV-1, from 10 4.3 to 10 3.5 TCID 50 /mL (mean across three replicates) ( Figure   100 1A).  Table 1). HCoV-19 and SARS-CoV exhibited similar half-lives in aerosols, 114 with median estimates around 2.7 hours, and 95% credible intervals (2.5%-97.5% quantile range) of 115 (1.65, 7.24 hours) for 5.45 hours) for SARS-CoV-1 (Table 1). Half-lives on copper 116 were also similar between the two viruses. On cardboard, HCoV-19 showed a considerably longer half-117 life than SARS-CoV-1. Both viruses showed markedly longer viability on stainless steel and 118 polypropylene: the median half-life estimate for HCoV-19 was roughly 13 hours on steel and 16 hours on 119 polypropylene. In general, there was no statistically discernable difference in half-life between the two 120 for use under a CC0 license. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available author/funder, who has granted medRxiv a license to display the preprint in perpetuity.

124
HCoV-19 has caused many more cases of illness and resulted in more deaths than SARS-CoV-1 125 and is proving more difficult to contain. Our results indicate that the greater transmissibility observed for 126 HCoV-19 is unlikely to be due to greater environmental viability of this virus compared to SARS-CoV-1. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint (which was not peer-reviewed) is the . https://doi.org/10.1101/2020.03.09.20033217 doi: medRxiv preprint more likely to die out by chance, but when outbreaks do occur they are explosive and can overwhelm 147 hospital and public health capacity. 24 A number of hypothesized super-spreading events have been 148 reported for HCoV-19. Given that SARS-CoV-1 superspreading events were linked to aerosol and fomite 149 transmission, 6-11 our finding that HCoV-19 has viability in the environment comparable to that of SARS-150 CoV-1 lends credence to the hypothesis that it too may be associated with superspreading.

151
We found that the half-life of HCoV-19 on cardboard is longer than the half-life of SARS-CoV-1.

152
It should be noted that individual replicate data were noticeably noisier for this surface than the other 153 surfaces tested ( Figures S1-S5), so we advise caution in interpreting this result.