This Morning hosts Holly Willoughby and Phillip Schofield spoke to Dr Chris on Monday as they discussed the effect of long Covid, of which numbers are rising.
He also talked about the fact the Pfizer vaccine has now been approved for us on 12-15-year-olds, and explained when the rollout is likely to begin.
Holly began: "It appears there are an awful lot of people still suffering from long Covid at the moment, this is an umbrella term for encompassing symptoms that persist for more than four weeks after you've had Covid."
Dr Chris replied: "Yes, over a third of a million people are suffering from long Covid one year after they caught the initial infection.
"The symptoms are fatigue, that's the most common one, and it can be quite severe fatigue.
"The other one is shortness of breath, muscular pain anywhere in the body, and also what we call brain fog, poor ability to concentrate, about one in ten people develop long Covid.
"It has actually quadrupled in the last month, is this due to the Indian or Delta variant?" he wondered.
Dr Chris continued: "This is very similar to the situation with flue and glandular fever, virus infections which can cause post-viral fatigue, sometimes known as chronic fatigue syndrome or ME.
"We know ME is an accepted after effect of a virus infection."
Asked by Phil about the Pfizer vaccine being approved for use in children, Dr Chris explained: "Yes, it's been approved by the medicines regulator, because it's safe and it's effective, so they have given it the green light.
"Why? The cases of Covid are actually increasing in children, this may be due to the Delta variant.
"There is also the impact on children's education if they get Covid, and of course they could get long Covid which could keep them fatigued and out of sorts for a long time.
"The ministers are going to be deciding if vaccinations of the 12-15-year-olds will start late August or early September."
Phil added: "We should say that instances of serious illness in children with Covid is very rare, especially long Covid, so it's precaution more than anything."
* This Morning airs weekdays on ITV at 10am
