March 24, 2020

expert comment on using food delivery services rather than supermarkets in response to COVID-19

There have been questions from journalists around using food delivery services rather than supermarkets in response to COVID-19.

Prof Sally Bloomfield, Honorary Professor, London School of Hygiene and Tropical Medicine, said:

“Any virus contamination would come from someone who has contaminated hands, handling the items whilst they are being handled for delivery.

“Although hands and hand contact surfaces are thought to be a major contributor to spread, the main risk comes from ‘hand contact surfaces recently and frequently touched by many other people’.  If you think about it the supermarket provides an ideal setting for this to occur – many people touching and replacing items, checkout belts, cash cards, carpark ticket machine buttons, ATM payment buttons, paper receipts – etc,etc – not to mention being in the proximity of several  other people

“By having home delivery – all of these risks are eliminated. By comparison we know – coronavirus does not ‘breed’ outside the body so by the time it is delivered any chance infectivity is already lower because the virus starts to lose its infectivity as soon as it leaves the infected person. Also the items have probably been touched by relatively few people. All of this means that the risk of home delivery is very small compared with visiting the supermarket. If you want to take further precautions then place all the items in the cupboards, fridge etc, where any residual viral infectivity will further decrease before you handle it again – and then wash your hands thoroughly.

“Remember there is no such thing as zero risk.”

Dr James Gill, Honorary Clinical Lecturer, Warwick Medical School, said:

“Yesterday Boris Johnson advised after the public lock down, people could look to use food delivery services as a way to reduce their need visit supermarkets. Looking at having groceries delivered highlights the importance of the imposed lock down, as social isolation and the restriction of movement is the strongest defence that the general public has against possible COVID19 infections.

“But should people be concerned about the possibility of coronavirus exposure from groceries delivered directly to their homes? The fight against this new pandemic is being driven by data, data that is rapidly evolving and being updated. The best possible action plans are derived from this data, but like this data they are open to change. Let’s use some of that data to see what current conclusions we can draw about going to the shops, and why, to repeat a point, social isolation is so important:

“In all likelihood, the risk of exposure to COVID19 from a food delivery is less than risks of exposure in going to the supermarket and the queues at the checkouts. We know coronavirus is spread via droplets when people cough. We believe that somewhere between 15-30% of infected patients can be asymptomatic in some groups – but whether they are also infectious as well has yet to be determined

“Let’s assume that asymptomatic patients are also spreaders. If you go to the shops for a few items and encounter 30 people, which is reasonable in a big supermarket, you could potentially be exposed to people infected with the virus who are not showing signs. By comparison, food delivered to the home can be done via ‘no contact drops’ reducing direct exposure to whoever is dropping off the food. But what about the shopping itself? Data on how long the virus may live on surfaces has recently been revised upwards with survival on plastics now thought to be possible for up to 3 days. Initially the longevity of the virus may cause concern over home deliveries, until we remember that wiping over surfaces with simple dilute household bleach will inactivate the virus within 1 minute.

“The safest option for the public is to stay indoors unless absolutely needed. Food deliveries, whether from friends/relatives or the supermarket courier will carry a lower risk of exposure than going to the supermarket, and most people have bleach and a cloth to be able to wipe over those home deliveries effectively eliminating risk”

All our previous output on this subject can be seen at this weblink: 

www.sciencemediacentre.org/tag/covid-19/

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