There is evidence that some cold viruses can "hit and hide".
Researchers Discover Cold Virus Can 'Hit And Hide'
An international team of researchers has discovered that respiratory syncytial virus (RSV), a common cold virus causing bronchiolitis in children, can act as a 'hit and hide' virus.
Professor Peter Openshaw, from Imperial College London and St Mary's Hospital, and one of the papers authors, comments: "These studies show that RSV is a 'hit and hide' virus, rather like HIV, herpes or some hepatitis viruses. The symptoms seem to go away but the virus is just hiding, waiting for a chance to re-emerge and begin infecting other people."
https://www.sciencedaily.com/releases/2004/04/040426055429.htm
Originally Posted by: RobN