While symptoms are generally less severe than earlier variants, the rate of Covid-19 hospital admissions in England is at the highest since January 2021.
Mr Johnson downplayed the chances of having to impose a lockdown again, but was holding on to the option in case even more concerning new variants emerge.
Speaking to Conservative MPs Esther McVey and Philip Davies for GB News, he said: “I want to avoid any such thing ever happening again and I can’t rule out something, I can’t say we wouldn’t be forced to do non-pharmaceutical interventions again of the kind we did.
“I think it would be irresponsible of any leader in any democracy to say that they’re going to rule out something that can save lives.
“I believe the things we did saved lives. I’ve got to be absolutely frank with you, there could be a new variant more deadly, there could be a variant that affects children, that we really need to contain, I’m not going to take any options off the table. But I don’t think it will happen.
“We’re now in the phase where the virus is losing its potency overall and we’ve got a massively vaccinated UK population.”
Research from the UK Health Surveillance Agency indicates the overall Covid-19 hospital admission rate for England hit 20.5 per 100,000 people in the week ending April 3.
That is the fifth successive weekly increase and means total admissions are now at a higher rate than at the peak of the original Omicron wave at the start of January this year (19.9).
But the rate is still some way below the all-time high of 36 per 100,000 in the first week of January 2021.