Study design
Patients were recruited from the COVID-19 outpatient clinic of the University Hospital of Londrina-Paraná, Brazil, from November 1, 2020, to February 1, 2021. The study was a prospective randomized triple-blinded randomized controlled trial. Participants were instructed to use nasal and oral rinsing protocols according to the following groups: Group 1, non-active mouthwash and saline nasal spray (SNS); Group 2, phthalocyanine mouthwash and SNS; and Group 3, phthalocyanine mouthwash and phthalocyanine nasal spray. They were instructed to gargle for 30 sec and rinse for 30 sec with 5 ml of the mouthwash solution and to spray two pumps of the nasal spray into each nostril five times a day for three consecutive days. Participants’ VLs were assessed using reverse-transcription polymerase chain reaction (RT-PCR) on the first and third days of using the mouthwash and nasal spray. Each participant’s adherence to the rinsing protocols was recorded.The inclusion criteria were patients aged 18 to 80 years who tested positive for SARS-CoV-2 and were diagnosed within 7 days of symptom onset. The exclusion criteria included patients with cycle threshold (Ct) values greater than 31 and patients who had contraindications to using mouthwash or nasal spray for medical reasons or because of an inability to gargle and spit. All participants received standard care (antibiotics, corticosteroids, and anticoagulants) according to the World Health Organization standard treatment guidelines [