The time period before a person who has been infected develops or presents with symptoms.
People infected with SARS-CoV-2 shed the virus even in the presymptomatic stage and tend to be most infectious one to two days before they develop symptoms.
The real-time Polymerase Chain Reaction (RT-PCR) test for COVID-19, can detect the virus in pre-symptomatic people, about a week before symptoms develop, as well as during infection, and for about six weeks after the person has recovered. Countries have found that most people only get tested once they have symptoms. This means people who are presymptomatic and are unaware that they have been infected don’t get tested resulting in an accurate reflection of the actual number of cases. In addition, concerns are that presymptomatic people who do not take preventative measures can infect others.
Infectious Disease Prevention Symptoms Transmission