Overlooking Portland. Picture: Michael Taylor ONLY one area of Dorset has no active coronavirus cases as Covid-19 cases continue to rise across the county. Public Health England breaks down the numbers of Covid-19 cases into neighbourhoods called 'Middle Super Output Areas' (MSOAs), which are smaller than council wards and based on population rather than geographical area. Government and Public Health England define a coronavirus cluster as an area where there are more than two coronavirus cases in a population size of 7,500 at any one time. The interactive map, which can be found online, allows users to type in their postcode and see how many cases were reported in their area and if it has increased or decreased from the week before.