Public Health England has not released a study showing supermarkets are the most common place to catch coronavirus, despite many news reports yesterday (November 19th).
National publishers Sky News and ITV and local outlets including the Manchester Evening News reported the story that new figures from Public Health England (PHE) showed supermarkets were the most likely place for people to be exposed to the virus.
But they have been slammed by retail bosses as “misleading and irresponsible” for misinterpreting the data, while Isabel Oliver, director of the national infection service for PHE, said “suggestions that supermarkets are causing Covid-19 to spread are inaccurate”.
The figures they quoted were from a weekly coronavirus surveillance report the health body publishes – and they were wrong.
What do the figures actually show?
When a person tests positive for Covid-19 and is passed into the NHS Test and Trace system, they are asked to list the places they went in the seven to two days before their symptoms started.
PHE cross-references these answers, and any location that two or more people reported becomes a “common exposure setting”.
It is true that this information is collected to try and identify possible outbreaks – but just because two people who later test positive were in the same place does not mean that is where they caught or passed on the virus.
For the 128,808 people who tested positive and were passed to Test and Trace between November 9th and 15th, there were 9,789 common exposure settings identified.
Of those, 1,796, or 18%, were supermarkets.
But there is nothing unusual about this.
Supermarkets can be very large places, visited by a lot of people on a regular basis. It is perfectly possible for two people who later test positive to have visited one and have no contact or viral transmission between each other.
They are also one of the few places currently open – so of course they are one of the few places people will report having been.
What about the other places people “catch” Covid?
Eagle-eyed readers will have also spotted in yesterday’s reports that 1.6% of people “caught Covid” in pubs, 1.1% in gyms, and 1% in restaurants and cafes.
Strange, considering they are currently closed in England.
That is because the seven to two day period before November 9th and 15th straddles both sides of the lockdown, which came into effect on November 5th.
It is misleading to compare supermarkets to gyms and pubs, when shops were open for the whole period while other settings closed midway through.
An example of really poor Covid data journalism from Sky here today - completely misleading, when you look at the stats they are referring to. Managed to cause a field day for PHE though fielding a surge of calls from people like me though! #ddj https://t.co/3pyGiAzALG
— Harriet Clugston (@HarrietClugston) November 19, 2020
Even in the previous weeks, the figures would have been affected by the fact that gyms, bars and restaurants were often closed in the worst affected parts of England where the most people tested positive, while supermarkets were open – skewing the national figures.
What do supermarkets say?
Helen Dickinson, chief executive of the British Retail Consortium, said the news outlets that misinterpreted the figures were “misleading and irresponsible”.
She said: “The figures do not explain how or where people became infected, they simply explain where people have visited.
“Supermarkets are one of the very few places that people can visit during lockdown so it is unsurprising that they feature strongly when people are asked where they have visited.
"Retailers have spent hundreds of millions on safety measures including perspex screens, additional cleaning, and social distancing, to keep customers and colleagues safe."