Watch a full report from ITV News Anglia's Rob Setchell.
Health bosses in Suffolk say they are taking swift action to stop the spread of the so-called Indian variant.
It's after four new cases of the variant were found in the county - three of them in the Needham Market area.
Today, hundreds of people in the town took PCR tests at a new mobile centre in the Mid Suffolk District Council building car park.
Anyone who lives or works in Needham Market has been invited to book in for the test even if they don't have symptoms. Appointments must be booked in advance online or by calling 119. A fourth case of the variant was found in Newmarket, while another was discovered earlier in the week in Mildenhall.
Stuart Keeble, Director of Public Health Suffolk, said: "We are taking this swift action, as a very small number of cases of this variant of concern have been found in the Needham Market area.
"There is no need for people to be worried, but we do need to act straight away and prevent the infection spreading further into the community.
"I am asking for residents and workers in Needham Market, to take a PCR test for COVID-19 as soon as possible.
"Otherwise please keep following the national guidance, washing your hands regularly, wearing a face mask, social distancing as necessary, opening up windows when people from other households visit and take up your vaccination when offered it."
In total, there have been 16 Covid cases in Needham Market and surrounding area in the last two weeks, with 71 cases in the whole of Suffolk.
It comes after a number of cases were identified at the nearby Wattisham Flying Station.
A British Army spokesperson said: