inclusion criteria: 1. subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. 2. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). 3. negative serology rapid test to covid-19. 4. be informed of the nature of the study and the procedures and sign an informed consent form. 5. willing and able to adhere to protocol requirements. 6. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.

inclusion criteria: 1. subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. 2. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). 3. negative serology rapid test to covid-19. 4. be informed of the nature of the study and the procedures and sign an informed consent form. 5. willing and able to adhere to protocol requirements. 6. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.

inclusion criteria: subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). negative serology rapid test to covid-19. be informed of the nature of the study and the procedures and sign an informed consent form. willing and able to adhere to protocol requirements. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.

inclusion criteria: subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). negative serology rapid test to covid-19. be informed of the nature of the study and the procedures and sign an informed consent form. willing and able to adhere to protocol requirements. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.

inclusion criteria: subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). negative serology rapid test to covid-19. be informed of the nature of the study and the procedures and signed an informed consent form. willing and able to adhere to protocol requirements. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.

inclusion criteria: subjects 12 yr and older who had not previously been infected with covid-19 to the best of their knowledge. were not vaccinated yet against covid-19 and will not be vaccinated during the study (if they decide to get the vaccine during the study they will be excluded a week later). negative serology rapid test to covid-19. be informed of the nature of the study and the procedures and signed an informed consent form. willing and able to adhere to protocol requirements. if female of childbearing potential, agree to use an acceptable method of birth control or be surgically sterile, and have a negative pregnancy test.