We believe easing of the lockdown, and the active encouragement to return to work, is premature and unsafe given the high rate of ongoing infection1, that the R0 value is very close to, and in some areas is above 1 and the test, trace and isolate system is months away from being properly functioning.  In addition, the return to work will disproportionately expose lower paid and BAME workers to increased risk of Covid-19 infection, the very groups who have already been hit so hard by this deadly disease.

The return to work however is being implemented by the government and indeed further plans are to be announced shortly, so it is important to look at the guidance.  There is separate guidance for schools which will not be discussed here, however the general principles will apply to schools too.

The government’s guidance for 8 sectors of the economy, “Working safely during coronavirus”2 gives us serious cause for concern.   It fails to take into account the way Covid-19 transmission occurs indoors, the time spent in enclosed spaces and the need to ensure proper ventilation.  The very high risk faced by BAME staff is not mentioned.  The guidance also downplays the importance of face coverings as well as weakening the 2m rule, making it advisory rather than a requirement.  There is frequent use of the phrase “whenever possible” throughout the guidance, creating uncertainty and allowing room for employers to choose whether or not to implement the provisions.  There is sensible advice in the guidance, such as the need to carry out a risk assessment of the workplace, on home working and on handwashing, use of sanitisers and cleaning and disinfection.  However these do not make up for the many deficiencies, which will result in people who work in offices, shops and other enclosed work places up and down the country, doing so in unsafe conditions and being exposed to Covid-19. 

Indoor transmission of Covid-19

Apart from early “super-spreader” events outdoors, transmission of Covid-19 is essentially an indoor phenomenon3, both through droplet spread and microdroplet aerosol spread4.  The 2m rule is of limited value: if people occupy the same enclosed space for any length of time, and ventilation does not meet required standards, aerosolised viral particles from an infected individual can spread through the available space and may be breathed in by anyone occupying that space.  A single cough can project over several metres, tens or even hundreds of millions of viral particles into the air5 and will contribute to the creation of an “aerosol rich environment” in an enclosed space.  The longer people occupy this space the greater the risk of inhaling sufficient viral load to get infected.  Even if strictly observed, the 2m rule will not offer sufficient protection in this situation. 

A number of studies have shown that enclosed indoor environments can result in high levels of transmission.6, 7, 8 They show one or two infected individuals can lead to a large number of other people being infected, even if they are several metres away from each other. 

Ventilation

The consideration of ventilation in the guidance is inadequate and vague, and fails to take into account the challenges of making indoor spaces safe from Covid-19. It does say face-to-face meetings should be held “outdoors or in well-ventilated rooms whenever possible.”  There is no mention of ventilation however in relation to workplaces and workstations, where large numbers of workers will spend most of their day.

Improving ventilation is mentioned in the government’s guidance for transport operators, as follows: “Organisations should consider how to increase ventilation and air flow. Where possible, transport operators and businesses should ensure that a fresh air supply is consistently flowing through vehicles, carriages, transport hubs and office buildings.”   Once more we see “where possible” and there is also a distinct lack of detail about the technical requirements for effective ventilation to eliminate this highly infectious new pathogen from public transport provision.  This will not lead to safe conditions for travel for the public.

Organisations with ventilation systems are advised to check them to see if they require servicing or adjustment “for example, so that they do not automatically reduce ventilation levels due to lower than normal occupancy levels.  Most air conditioning systems do not need adjustment, however where systems serve multiple buildings, or you are unsure, advice should be sought from your heating ventilation and air conditioning (HVAC) engineers or advisers.”  There is no technical guidance here about type of ventilation required, and issues like the number of air changes per hour etc.  And what of premises were there is no ventilation system?

The absence of guidance on ventilation is all the more surprising given the detailed advice on this from Public Health England: “Covid-19: Infection prevention and control guidance”.9 While this is written for health care settings and much of the detail is not applicable, the facts of known asymptomatic spread of Covid-19, the aerosol route of transmission of the virus, and the ongoing high level of community infection mean that all indoor spaces are a potential hazard.  The general principles of this guidance should therefore apply to all indoor spaces, but they do not appear to have been considered, apart from that stated above.

BAME staff

Nowhere in the guidance is the very high risk from Covid-19 for BAME people mentioned.  Death rates are 4 times as high for some BAME groups, yet section 2.1 in the guidance for shops, on “Protecting people who are at higher risk” makes no mention of this.  The risk of dying from Covid-19 for people with diabetes, (included in the “clinically vulnerable” group of the population requiring extra protection) is exceeded by that for people of a BAME background.  This cannot be right, and as long as serious risks like this are not addressed, the current high death rates will continue.

Social distancing

There is over-reliance in the guidance on the 2m rule to keep workers safe, and as we have said, throughout the guidance this is weakened by the phrase “where possible”.  Where 2m distancing is not possible employers should “manage transmission risk” by among other things, “using back-to-back or side-to-side working whenever possible”.  Sitting side-by-side or back-to-back will not prevent people from breathing in aerosolised virus, as the studies clearly demonstrate, and people do not rigidly stick to one head position, they move around and turn especially when speaking to those around them.  This weakening is consistent with the constant drip feeding in the media suggesting that the 2m rule is not really essential, compromising the social distancing message overall still further.

A recent study in the Lancet showed that reducing distances is associated with increased risk: infection risk doubles when the distance between people is halved from 2m to 1m10.

Face coverings

The government’s recent about turn on the wearing of face coverings is welcome, as belated as it is.  However, the advice on face coverings in the return to work guidance almost seems to be designed to put people off from wearing them: “There are some circumstances when wearing a face covering may be marginally beneficial as a precautionary measure.”  Again, this is reproduced throughout the guidance documents. 

We recognise there will be some areas and job roles, and for some individuals, where it is not practical or advisable, but face coverings should be worn everywhere in the workplace as a means of source control for transmission of Covid-19, unless there is a demonstrable reason not to do so.

Duration of time, activity levels and size of work space

These three further risk factors for indoor transmission are also not considered in official guidance.  The longer the time people spend together in an enclosed space the greater the risk of inhaling sufficient virus to become infected.  Similarly, the smaller the space the greater the risk.  In addition if people are highly active, for example through physical exertion leading to heavy breathing, or laughing or shouting, excretion of virus is significantly increased from infected individuals, adding to risk of infection in an enclosed spaces.

Conclusion

Official guidance on return to work is inadequate and will leave very many people exposed to risk of infection with Covid-19.  Making workplaces safe in the era of Covid-19 is nigh impossible given the scale of changes required with ongoing high levels of viral transmission in the country.  The only way to keep people safe at work is to drive down transmission to much lower levels and have in place a reliable and highly efficient test, trace, isolate and support system.  Current government plans are very risky and threaten to drive a second wave of the pandemic in the UK.

References

  1. Estimated to be 17,000 new infections per day by the MRC Biostatistics Unit on 5 June 2020. https://www.mrc-bsu.cam.ac.uk/now-casting/
  2. https://www.gov.uk/guidance/working-safely-during-coronavirus-covid-19
  3. https://www.medrxiv.org/content/10.1101/2020.04.04.20053058v1.full.pdf
  4. https://science.sciencemag.org/content/early/2020/05/27/science.abc6197
  5. https://www.pnas.org/content/early/2020/05/12/2006874117
  6. https://wwwnc.cdc.gov/eid/article/26/7/20-0764_article#tnF1
  7. https://wwwnc.cdc.gov/eid/article/26/8/20-1274_article
  8. https://www.latimes.com/world-nation/story/2020-03-29/coronavirus-choir-outbreak
  9. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/886668/COVID-19_Infection_prevention_and_control_guidance_complete.pdf
  10. https://www.thelancet.com/action/showPdf?pii=S0140-6736%2820%2931142-9

Doctors in Unite Statement, 10/06/2020