The CNN anchor John King has disclosed on air that he has multiple sclerosis. King brought up his diagnosis while discussing the death of the former US secretary of state Colin Powell, on Monday, of complications from Covid-19.

Powell, who was immunocompromised after a multiple-myeloma cancer diagnosis, died despite being vaccinated. "I'm going to share a secret I have never shared before. I'm immunocompromised. I have multiple sclerosis. So I'm grateful you're all vaccinated," King, who took part in this year's Irish Times Winter Nights festival, said during a panel on his programme, Inside Politics. He added that although he does not "like my boss telling me what to do" he thanks his employer for requiring vaccinations to keep those such as him safe. "In this case, it's important."

It's unclear exactly how common breakthrough infections are, but recent outbreaks suggest that the number may have increased after the arrival of the Delta variant. Still, most vaccinated people who get infected are likely to have mild symptoms. And they may even benefit in the long run by strengthening their immune system's defences against variants. The US Centers for Disease Control and Prevention has said that those who are immunocompromised may not always be fully protected after an initial vaccination and should continue to take all precautions. The CDC also recommends that moderately to severely immunocompromised people receive a booster shot. – This article originally appeared in The New York Times