The ex BBC Breakfast said cancer “unfortunately did not disappear” during the outbreak and told those concerned to seek advice.
The journalist was diagnosed with prostate cancer in 2017.
Bill was later told it has spread to his spine, ribs, pelvis, hips and legs.
In May, he revealed he has to have a radioactive isotope injected into him once every six weeks.
He said: “It makes you so live, so to speak, that I have to sleep in a separate room for three days, no prolonged contact with small children or pregnant women for six days.”