Since the emergence of the SARS-CoV-2 delta strain and widespread vaccination, the landscape of viral detection has changed immensely. Firstly, the delta strain has a rapid onset of infection, with peak viremia (and therefore infectivity) before symptoms appear. Secondly, vaccination prevents severe disease in most people, but does not preclude infections in vaccinated people. Indeed, these people can, even when free of symptoms, pass the virus on to others.

Since the emergence of the SARS-CoV-2 delta strain and widespread vaccination, the landscape of viral detection has changed immensely. Firstly, the delta strain has a rapid onset of infection, with peak viremia (and therefore infectivity) before symptoms appear. Secondly, vaccination prevents severe disease in most people, but does not preclude infections in vaccinated people. Indeed, these people can, even when free of symptoms, pass the virus on to others.