Surge testing is being carried out in in three new areas in Hampshire and Surrey following confirmed cases of the Indian Covid strain.
Everyone aged 12 and over who lives or works in specific postcodes in Hart District, Rushmoor Borough and the Surrey border are being urged to be tested on Wednesday whether they are showing symptoms or not.
All the confirmed cases have been instructed to self-isolate and their contacts have been identified.
Further targeted testing is also being carried out in schools in all three areas.
Enhanced contact tracing will be used for people who test positive with a variant of concern (VOC).
This is where contact tracers look back over an extended period to determine the route of transmission.
Anyone with Covid symptoms are being urged to book a free test online or by phone before visiting a testing site or have a kit sent to their home.
Residents are also being urged to use lateral flow tests twice weekly.
The news comes as encouraging data shows Covid cases have fallen sharply in all but one of England's 10 hospital trusts treating the most patients with the virus.
Bolton - which has the highest infection rate in the country after being heavily hit by the Indian variant - has seen a month-on-month increase, with 11 more hospitalised patients than a month ago.
All regions in the country have seen the number of coronavirus patients more than halve in the month to Tuesday last week.
NHS England data shows that on April 18, there were 861 people in hospital in England with the virus - but this had fallen sharply to 364 a month later.
The data raises hopes that Boris Johnson's plans to ease Covid restrictions on June 21 can go ahead.
The government has said that hospitalisations and new infections need to fall in order for restrictions to be lifted.
The Prime Minister last week reiterated the UK still needed to be "cautious" in unlocking the UK from restrictions - but that he saw nothing in the data that would suggest "deviating" from the plan.
And he said he would give "as much information" as possible by the end of the month - which suggests an announcement this week.
