14 January 2021

Are the people to blame for the Covid spread – or are we using the wrong control measures?

By Professor Ashley Woodcock

As we near 100,000 deaths in the UK so far, the Covid-19 epidemic is still accelerating rapidly. But though it looks very much as though the new variant of the virus is more transmissible, it’s still not clear exactly how it is being transmitted.

The collective dogma, promoted by SAGE in the UK and the CDC across the pond, is that Covid is a flu-like virus transmitted in aerosols. However, current control measures against aerosols (which do seem to be preventing any influenza this year) are ineffective against Covid, short of locking people in their homes.

It seems increasingly likely that the virus is highly infectious by other routes, spreading by direct and indirect contact, droplets, and by faecal-oral transmission. It is excreted in faeces, is persistent on surfaces in public areas, and could also be present in the cold food chain. What’s more, recent data from “track and trace” suggests that the greatest risk was visiting a supermarket.

As for transmission by aerosol (small particles), this seems unlikely in the community, outside hospitals, and certainly in the outdoors. Indeed, viable airborne virus in an aerosol has never been detected in the community. It’s worth noting too that viruses like chicken pox and measles, which are transmitted as viable virus in aerosols, have a much higher R0 value than Covid, in the 10-15 range. Even in the close confines of a plane, airborne transmission seems to be an extremely rare event. 

Nor does widespread mask-wearing seem to have had much impact on the progress of the epidemic. They get immediately contaminated at the first cough or sneeze, and then contaminate the hands when they are frequently adjusted.

Faecal-oral spread?

Anyone carrying Covid in their mouth and nose who coughs or sneezes onto the hand will transfer virus onto the door handle, the chilled food in the supermarket, or the food or beer glass they serve in the pub. Physical separation will separate you from cough droplets, but it also reduces mutual physical contacts by maintaining your personal space. Similarly, inadequate hand washing after using the toilet (>30secs with soap) could result in faecal-oral transmission.

Covid is present in the gastrointestinal tract early and late in the disease. It is found universally and earliest in the mouth/throat, where it forms the basis for all early diagnostic tests. We all touch our faces (and facemasks) frequently, and virus can be transferred from contaminated surfaces, and hands to face/mouth. It has also been found in faeces and in sewage. We know too that the virus persists on indoor surfaces, especially on stainless steel and plastics , and on mobile phones, cashpoints and supermarket tills for up to 28 days.

Infection in hospitals

In hospitals, SARS-CoV-2 RNA is found widely on surfaces in public areas, which suggests hospitals and hospital staff are a major source of infection. Increasing numbers of inpatients who arrive with other conditions are developing Covid in hospital. Hospital staff also have high levels of infection and seropositivity, and they must be a major source of infection both in their own households and the wider community. All of which means that hospital infection control measures require urgent tightening.

Food chain and shops

Another focus of attention should be the food chain and the places we buy food. It’s possible that Covid could be present in the cold food chain, on food packaging, and by contamination by food handlers. Food manufacturers and distributors, supermarket shelf-stackers and till operators, waiters and bar staff could all be sources of infection.  Covid is killed by heat, but survives much longer in cold conditions and could persist in chilled and frozen foods, or on the packaging

We saw this in China in early July 2020, when Covid was detected on frozen foods, including their packaging materials and storage environments, with two re-emergent outbreaks linked to contaminated food sources. There have also been large outbreaks amongst workers in a chicken factory and a Danish abattoir. Buffet meals using common serving utensils are a potential risk. 

Here in the UK the Food Standards Agency (FSA) have now commissioned research on Covid in food, on packaging, and in shops. It’s possible that the virus could be like Norovirus, which is transmitted by faecal-oral spread from asymptomatic food handlers. Bear in mind that, according to the FSA, between one fifth and one third of norovirus transmission is from salads and berries

The above data suggests that it may be the control measures rather than individual lapses that are responsible for the escalating epidemic. In addition to the emphasis on maintaining distances and facemasks, Public health strategy should re-focus on improved hygiene to control transmission from contaminated surfaces and via the faecal oral route. This change in thinking would enable a much more proactive approach to infection control, with a major emphasis on prevention of transmission through improved hygiene. 

Here are a number of important steps businesses and other organisations could take to keep vulnerable people separate and safe until they are vaccinated. Some of these steps may seem onerous, but the scale of the epidemic means we must strain every sinew to keep infections as low as possible, especially now the end is in sight.

  • Use of sanitisers to be compulsory on entry and exit to all supermarkets and shops
  • Every cash dispenser, supermarket till, credit card machine fitted with automatic hand sanitiser for use before and after.
  • Test food manufacturers, all parts of the cold chain, and especially food handlers in shops and supermarkets very frequently for SARS-CoV-2 
  • Improve hygiene in the food chain, and especially at supermarkets. Give all workers reinforced training emphasising vigilance and  cleaning at every contact
  • Stop shoppers checking “sell-by-dates’ and returning food back to shelves
  • Consider mobilising military personnel to help clean hospital public areas, schools, nursing homes, public transport, shops and restaurants 
  • Consider how salads and similar products are irrigated, and the potential for infection.

There are also steps we as individuals can take to try to keep infections as low as possible.

  • Quarantine all goods coming into the home and wash food packaging with soap or alcohol. There’s guidance on how to do this here.
  • All elderly and vulnerable wear and then rinse reusable rubber gloves in detergent to be used for receiving post, newspaper, food deliveries 
  • Vulnerable people avoid uncooked foods, salads and shop-bought sandwiches
  • Clean your homes – every surface, tap, door handle, utensil and crockey, as well as cars and clothing. 
  • All clothes used in last 72 hours go into hot wash cycle. 
  • Repeating this exercise several times would be an effective supplement to lockdown.

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Ashley Woodcock is a Professor of Respiratory Medicine at the North West Lung Centre, University Hospital of South Manchester.

Columns are the author's own opinion and do not necessarily reflect the views of CapX.