2.3 The lifecycle of a viral infection

2.3. The lifecycle of a viral infection | Te huringa o te mate huaketo

The lifecycle of viral infection in a person has several stages. The process begins once a person has been exposed to the disease pathogen and becomes infected (for example, SARS-CoV-2 as illustrated in Figure 4). Following this there is an incubation period, where the pathogen multiplies, but the host will not be aware they are infected. After incubation, the infected person enters the 'live virus' stage in which the SARS-CoV-2 virus is actively replicating in the body and the person is infectious.

There will be a few days between becoming infectious and symptoms beginning to emerge. If a person is infectious before they know they are sick, they may not know to take precautions against spreading the illness to others. This is particularly the case if the early symptoms are minor and easily overlooked.

Figure 4: COVID-19 infection stages

Source: Tim R Mercer and Marc Salit, 'Testing at scale during the COVID-19 pandemic', Nature Reviews Genetics, 22, (2021), pp. 415–426