At the same time as parts of Italy were being overwhelmed by COVID-19, the UK government was downgrading the risk from COVID-19

I have been reading a couple of reports looking at the UK government’s guidance on the use of Personal Protective Equipment (PPE) for healthcare workers whose patients may be infected with COVID-19. One report by Dinah Gould and Edward Purssell was commissioned by the Royal College of Nursing and is pretty damning of the process by which the guidance was drawn up and the (lack of) evidence cited. But it is the other report, by a Health and Safety consultant David Osborn*, that astonished me when I read it Friday evening. COVID-19, the disease that has killed over 100,000 people in the UK, and millions worldwide, is not classified by the UK government as a “high consequence infectious disease” (HCID). This surprises me. Even more remarkably, it was considered a HCID until mid-March 2020, when it was downgraded. If you don’t believe me (and I wouldn’t blame you here), the official UK government page is here. If you remember, March 2020 was about the time that COVID-19 was overwhelming the healthcare system of parts of northern Italy, forcing the Italian government to send in the army. On the face of it, downgrading the official risk classification of an infectious disease at the same time as that disease is overwhelming the healthcare system of another European country is a surprising decision.

The official definition of a HCID is that the disease should be:

  1. acute infectious disease
  2. typically has a high case-fatality rate
  3. may not have effective prophylaxis or treatment
  4. often difficult to recognise and detect rapidly
  5. ability to spread in the community and within healthcare settings
  6. requires an enhanced individual, population and system response to ensure it is managed effectively, efficiently and safely

To take these six points in order: 1. I am not a medic but I assume it satisfies the first; 2. COVID-19’s average mortality rate is around 1% (but varies dramatically with age and other factors); 3. in March 2020 we had no vaccine and no treatment; 4. COVID-19 can be transmitted by infected people who show no symptoms at the time of transmission; 5. it was spreading both in the community and in healthcare settings in March 2020; 6. in March 2020 we as individuals changed our behaviour, as did the NHS, and it still killed many thousands. Unless the approximately 1% mortality rate is not considered high enough, then it looks to me as though COVID-19 satisfies all six of these points.

Whether COVID-19 is classified as a HCID or not, is not a mere administrative detail. I think, simply speaking, if a disease is a HCID then healthcare workers are told to wear full PPE when caring for patients who may have or definitely have that disease. The PPE would include proper fit tested FFP2/FFP3/N95 masks, as well as visors etc. If a disease is not a HCID then healthcare workers may only be wearing surgical masks when they care for COVID-19 patients (at least under some circumstances). This makes a difference, colleagues at Bristol and I are working (preprints here and here) on understanding masks, as are many others. I think the consensus is that a properly fitted FFP2/N95 PPE mask probably reduces the viral exposure by at least a factor of 100, possibly a 1000 or more, whereas an OK-fitting surgical mask probably reduces it by a factor of about 2 to 10**.

So I can see why the Royal College of Nursing is unhappy with current government guidance. If I were a nurse caring for a COVID-19 patient I would not want to be wearing just a surgical mask, I would want a mask that reduces the virus I inhale by at least a factor of 100.

* Thanks to Prof Greenhalgh on Twitter, where I saw this. This post just looks at one thing I learnt from Osborn’s report, there are other eye openers in that report; it is well worth a read if you are interested in COVID-19 transmission/infection control.

** For example, see a Health and Safety Executive report


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