with an evolution over the pandemic period that mirrored the 70 epidemiological observations of SARS-CoV-2 infection in Switzerland [8] (Fig. 1B) . The first cases 71 occurred early March with a peak of the COVID-19 epidemic mid-March followed by a 2 weeks 72 stationary phase before a slow decrease. Interestingly, the median viral load was higher in the first 73 phase of the outbreak as compared to the following period.
. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted July 16, 2020. . https://doi.org/10.1101/2020.07.15.20154518 doi: medRxiv preprint
The initial viral load of SARS-CoV-2 was compared to 6'050 RT-PCR of 14 other respiratory viruses [9] 75 and showed comparable median values ( Fig. 2A) . We then investigated SARS-Cov-2 viral loads 76 stratified by gender, samples type, age, and hospital units. A higher number of tests was achieved in 77 women than in men (35% of difference); however the rate of positive results was similar for both sex 78 ( Fig. S1A and B) and both genders showed comparable viral load distribution (Fig. 2B) . Stratification of 79 positive samples by age groups showed that older individuals, when tested, were likely to be is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. . https://doi.org/10.1101/2020.07.15.20154518 doi: medRxiv preprint viral load appears to be a poor predictor of disease outcome. Indeed neither the initial nor the highest 127 viral load of patients latter admitted to the ICU was significantly higher than the specimens from 128 patient treated in a SU. This absence of correlation with the clinical outcome is also supported (i) by . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
The copyright holder for this preprint this version posted July 16, 2020. . CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted July 16, 2020. . https://doi.org/10.1101/2020.07.15.20154518 doi: medRxiv preprint