He added: “It incubates there for seven days: if it gets to a certain viral load, then it drifts down through the trachea into the lungs, which causes symptoms.”
A nasal spray would destroy the virus, but require a regular application to maintain its effectiveness.
As such, it would serve as another tool people could use rather than a definitive solution to contracting the disease.
Doctors have warned people not to conflate them with vaccines, which train the immune system to prevent infection.