inclusion criteria: * agree not to participate in any other sars-cov-2 prevention trial during the study follow-up. * capable of using diary without difficulties (if applicable, with assistance by caregiver).

inclusion criteria: * agree not to participate in any other sars-cov-2 prevention trial during the study follow-up. * capable of using diary without difficulties (if applicable, with assistance by caregiver).

inclusion criteria: agree not to participate in any other sars-cov-2 prevention trial during the study follow-up. capable of using diary without difficulties (if applicable, with assistance by caregiver).

inclusion criteria: agree not to participate in any other sars-cov-2 prevention trial during the study follow-up. capable of using diary without difficulties (if applicable, with assistance by caregiver).