We extracted aliquots of collected surface samples by using the QIAGEN QIAamp Viral RNA Mini Kit (QIAGEN, ) and analyzed them for the presence of viral RNA by using a quantitative reverse transcription PCR assay targeting the E gene ( 4). We collected samples at specified timepoints and analyzed them for infectious virus by using endpoint titration. We assessed stability under 3 environmental conditions: 4☌/40% relative humidity (RH), 21☌/40% RH, and 27☌/85% RH (RH applies only to exposed surface samples). We aliquoted 50 μL of each fluid containing 1 × 10 5 50% tissue culture infective dose/mL SARS-CoV-2 into sealed tubes (liquid setting) or onto polypropylene disks (surface setting), as previously described ( 3). We acquired pooled human nasal mucus and sputum commercially (Lee BioSolutions Inc., ) and mixed it with SARS-CoV-2 (SARS-CoV-2/human/USA/USA-WA1/2020) ( 2). We describe SARS-CoV-2 stability in human nasal mucus and sputum under different environmental conditions. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is shed predominantly in upper and lower airway secretions ( 1), and transmission likely occurs predominantly through respiratory droplets, and potentially through direct contact and fomites.
