The investigational drug
CAVITY
The investigational drug SA58 was prepared into 2 ml prefilled sprayer (20 sprays per bottle), containing 5 mg of anti-SARS-CoV-2 mAb per ml. Placebo, only without anti-SARS-CoV-2 mAb as compared with SA58 Nasal Spray, was also prefilled into bottles with identical package that could not be easily distinguished by their appearance. The drug and placebo were self-administered by nasal sprays with a video instruction. When used, insert the sprayer nozzle into each nose nostril and press the pump to spray 0.1 ml of the nebulized solution into the nasal cavity. Each administration of the drug consisted of two sprays with one spray in each nostril, and a total of 1 mg antibody was administered into both nostrils. For an ordinary exposure day, 5–6 administrations of SA58 or placebo were recommended at an interval of 3–4 h per administration, with the last administration given before going to bed.