SARS-CoV-2, the virus causing Covid-19, can last in the lungs of certain individuals for up to 18 months after infection, finds a study.

The study, published in the journal Nature Immunology, showed that Covid virus persistence appears to be linked to a failure of innate immunity (the first line of defence against pathogens).

One to two weeks after contracting Covid, the SARS-CoV-2 virus generally becomes undetectable in the upper respiratory tract. But, some viruses persist in the body in a discreet and undetectable manner after causing an infection.