ARM 1: Coprimary outcome 1Incidence of COVID-19 in cancer patients using interferon-alpha as prophylaxis without known positive contact with COVID-19.COVID-19 confirmed by qPCR from respiratory swab .[3 months from baseline.];ARM 1: Coprimary outcome 2.incidence of any upper or lower community acquired respiratory viral infection (define as identification of respiratory viruses such as coronavirus other than SARS-CoV-2; influenza; parainfluenza; respiratory syncytial virus; rhinovirus; adenovirus; human metapneumovirus).assessed using local standard of care testing (e.g. respiratory swabs; saliva and/or blood)[3 months from baseline.]

ARM 1: Coprimary outcome 1Incidence of COVID-19 in cancer patients using interferon-alpha as prophylaxis without known positive contact with COVID-19.COVID-19 confirmed by qPCR from respiratory swab .[3 months from baseline.];ARM 1: Coprimary outcome 2.incidence of any upper or lower community acquired respiratory viral infection (define as identification of respiratory viruses such as coronavirus other than SARS-CoV-2; influenza; parainfluenza; respiratory syncytial virus; rhinovirus; adenovirus; human metapneumovirus).assessed using local standard of care testing (e.g. respiratory swabs; saliva and/or blood)[3 months from baseline.]