Saliva sample collection
STERILE, VIRUS
All participants received a sealed self-test kit containing 5 self-collection saliva vials (OMNIgene Oral – OME-505, DNAgenotek, Ottawa, Canada), one for each different time point, and were given instruction to refrain from eating, drinking, chewing gum or performing oral hygiene for at least 30 minutes prior saliva collection (as per manufacturer’s instructions). Participants were then asked to collect a baseline sample of non-stimulated saliva by pooling saliva in the floor of their mouth without swallowing, and then to spit into the sterile vial until the amount of liquid saliva reached the 1 ml indication. At 30 minutes, 1, 2 and 3 hours after rinsing (test groups) or no rinsing (control group) participants were requested to collect saliva following the same recommendations than at baseline. After collecting saliva, patients were instructed to place the vials inside a sealed bag containing absorbent paper in case of opening or breaking of saliva tube. Samples collection was supervised by investigator conducting the study visit.The self-collection saliva vials contained solution used to inactivate the SARS-CoV-2 virus and stabilise viral nucleic acids at room temperature. After deactivation the saliva samples were stored at room temperature and then transferred to the Blizard Institute, Queen Mary University of London within 3 weeks for viral load analysis. Subsequently, samples were stored in a − 80 °C freezer until destruction in accordance with local guidelines and following the Human Tissue Authority (HTA) Code of Practice.