It comes after a study conducted by King’s College London suggested that around one in 20 people who catch coronavirus are likely to have long-term symptoms.
The figure rises to one in 10 people among those under the age of 50, the Health Secretary told MPs.
Mr Hancock revealed the stark news during a statement on coronavirus in the Commons.
He said: “We have already seen worrying numbers of young, fit, healthy people suffering debilitating symptoms months after contracting Covid.
“Yesterday, a study by King’s College London showed that one in 20 people with coronavirus are likely to have virus symptoms like fatigue, breathlessness, muscle pain and neurological problems for eight weeks or more.”
ITV News' Natalia Jorquera details the symptoms of Long Covid
After Labour’s John Spellar (Warley) asked for more data on the matter, Mr Hancock added that the Department of Health had two points of evidence.
“One is the evidence from King’s College London which shows that around one in 20 people with coronavirus are likely to have these long term symptoms," he said.
“The other evidence actually implies that in the under 50-year-old adults – it is more like 1 in 10. So there does seem to be some sort of correlation which implies that it is more of a problem amongst younger people."
Mr Hancock added that research into long Covid is still in its early stages and that further study is needed.
He also announced that Stoke-on-Trent, Coventry and Slough will move into the Tier 2 “high” coronavirus level at one minute past midnight on Saturday.
The Health Secretary outlined the new measures for Stoke-on-Trent, Coventry and Slough, where he said there has been a rising rate of infections.