There is no fixed timeframe for how many days it takes to detect neocoronavirus close contacts by nucleic acid testing; it is not detectable if they are not infected, and if they are infected, it is usually 1 to 14 days.
If a close contact, despite a history of close contact with a confirmed case, does not develop neocoronavirus infection due to strong autoimmunity or relatively good protective measures, such as wearing a mask and disinfecting it in a timely manner, the nucleic acid test will not show a positive result.
However, if infection is present, especially with the currently prevalent Omicron variant strain, the incubation period averages 1 to 14 days, so the time period is generally between 1 and 14 days, and the majority of infected individuals are able to be detected. The specific situation varies from person to person, so consult a medical professional for advice.