A mass Covid-19 testing trial in Liverpool has found 700 people unknowingly had the virus.
Public Health England director Dr Susan Hopkins said nearly 100,000 people had been tested over the last 10 days.
She stressed that these positive cases would have not been detected otherwise.
About 2,000 soldiers have been deployed in the city for the project, which was intended to run for an initial period of 10 to 14 days.
Devices which give results within an hour have been used to test people in the city since the scheme began on 6 November.
Liverpool had among the highest rates of deaths from coronavirus in October, when it became the first area in England to face the tightest restrictions before the second national lockdown.
Speaking at a Downing Street press briefing, Dr Hopkins said "we are looking to replicate this across the country".
She said: "We are also running evaluations in schools and universities and are planning to test university students prior to going home at Christmas."
Defence Secretary Ben Wallace visited a test centre at Exhibition Centre Liverpool on Monday and said the Army would assist with the programme for "as long as there is a need".
Mr Wallace said: "The rollout's been good, the soldiers have been welcomed, the public have come from all over the city."
Trooper Dan House, 22, said up to 500 tests a day were being carried out at the site where he was based and people had given soldiers tubs of chocolates as a thank you.
He said: "It's nice to know the work we're doing is coming across to the British public and they're happy we're here."