Study Design:~This is a 2 arms, Randomized, double blind, placebo controlled clinical trial.~Study population:~Subjects who, were not diagnosed with COVID-19 previously to their best knowledge and according to COVID-19 antibody test.~Were not vaccinated yet against COVID-19 and will not be vaccinated during their participating in the study.~Up to 1000(500 per study arm) will be enrolled for the purpose of this study.~Study treatment:~TaffiX™ will be used daily (up to 3 times a day, every 5 hours) in addition to the protective measures instructed by the Ministry of Health The control group will be administrated with Placebo- lactose powder for nasal application~Participation duration:~Up to 6 weeks~Concomitant therpay:~Allowed- no restriction for Concomitant Medications~Planned interim analyses:~When no less than 150 subjects have completed the study, an interim analysis for Efficacy and safety will be conducted by an independent biostatistician.~After no less than 500 subjects, additional interim analysis for Efficacy and safety will be conducted by an independent biostatistician.~Serious adverse events will be monitored by an independent safety officer on an ongoing basis throughout the study.~Stop Rule:~If the proportion of COVID-19 positive rate in the treatment group is statistically significantly lower than the proportion of COVID-19 positive rate in the placebo control group.
TAFFIX is a nasal powder spray that immediately creates a protective acidic barrier on the nasal mucosa against infection by inhaled viruses. The protective barrier lasts 5 hours.~TAFFIX is approved as a medical device in Israel, intended for use to block inhaled viruses within the nasal cavity. In Europe, it is registered as a medical device indicated for use as a protective mechanical barrier against allergens and viruses (e.g., SARS-CoV-2) within the nasal cavity.~TAFFIX is used as additional safety mean together with masks, hygiene, and social distancing.~The study rationale is to evaluate whether daily use of TaffiX™ as prophylaxis will reduce the rate of SARS- CoV-2 infection and other upper respiratory infections, compared to the placebo control rate.