Unfortunately there is currently a resurgence of measles in the UK. Measles is notoriously highly infectious amongst those who are not vaccinated. So it makes sense that the NHS should offer guidance on how to minimise measles transmission. But this guidance contains a recommendation which is, on the surface, just bizarre.
If a patient is infected with measles, they may be highly infectious. They may be breathing out the virus in their breath. One way to reduce the risk of transmission would be to ask the patient to weak a mask – if possible and if it does not interfere with their treatment or breathing. Masks are air filters worn on the face, and so if a measles patient is wearing a well fitted mask, the mask will filter out a fraction of the measles virus from their breath. Reducing the amount released to the room air.
There are basically three mask standards used in the UK: surgical mask (a terrible standard), FFP2 (a good standard), and FFP3 (for even more protection than an FFP2). So sane source control guidance from the NHS would probably recommend an FFP2 or even an FFP3 if possible, be worn – if it does not interfere with care and breathing.
This is not what the NHS is doing, the relevant part of NHS guidance is:
2.3.2. Surgical face masks as source control
If the patient has confirmed or suspected measles, then if possible/tolerated the patient should wear a surgical face mask (type I/II/IIR) in communal areas (for example, during transfer). The request for patients to wear a facemask must never compromise their clinical care.
Note: FFP3 respirators or powered respirator hoods must never be worn by an infectious patient.
Guidance for risk assessment and infection prevention and control measures for measles in healthcare settings, NHS 24th Jan 2024
The NHS is specifically forbidding wearing the best form of source control for a diseases such as measles!
On the face of it this a bit like the NHS issuing guidance on HIV transmission that says condoms should never be worn. Very odd.
I have tried to rationalise this guidance, to work out what the people who drew up this guidance – in secret – were thinking of. The FFP3 filters do offer some resistance to breathing (as do surgical masks) so I can imagine that for some patients they may not be appropriate. But forbidding them for all patients is just odd.
And the problem is compounded by the fact the NHS develops guidance for infection prevention in complete secrecy. I do not know who developed this guidance or what their reasoning was. Without knowing this, it is hard to challenge, or to justify. I have written to my MP about the topic of this post. It is a technical point so a bit hard to describe simply, but we will see.
Chance & Necessity 