How are the figures counted?
Data by Public Health England shows the number of Covid cases reported week by week from March last year through to last week.
These figures are broken down by small areas in England (towns, villages or even wards) called MSOAs.
To protect the privacy of individuals, data for areas that in one particular week reported fewer than two cases comes up as 'suppressed'.
This means that it is impossible to know how many cases were recorded there in weekly periods when figures were between zero and two.
Why does it matter?
When trying to work out the total number of infections reported in each MSOA since the start of the pandemic, the lack of data affects the overall total.