Here’s the thing. Huge rise around the world of people suddenly losing their sense of smell, some go on to develop Coronavirus symptoms, some don’t. Are the latter asymptomatic carriers of the virus?

The UK’s ENT association thinks they are and sees anosmia bad a marker of Covid-19. KCL study argues it’s a strong predictor of testing postive. French gov thinks it’s a marker and tells people to self-isolate. UK Gov says, ‘anecdotal’.

How could we know? Well, if we tested those with sudden onset anosmia we could find the numbers who were carrying the virus. But UK Gov does not test. Only those with the symptoms- and on Friday they excluded loss of smell from the symptoms because ‘anecdotal’

Looks like Catch 22. But another source of evidence for loss of smell as a marker of Covid-19 has arisen. Clinicians and front line workers are now being tested. Several have been exposed to the virus, and a proportion have sudden anosmia.

Several doctors and nurses on front line duties who have lost their sense of smell are now coming to be tested as NHS staff. Already we have heard of asymptomatic carriers with anosmia testing positive for CV, as documented by @mrsimongane and colleagues.

If the evidence coming more and more to light as people are tested that those with sudden loss of smell are asymptomatic carriers of the virus, then NhS staff being at work with this profile may be unknowingly spreading the virus and

Anyone going into care homes, or caring for the elderly, or volunteering to assist those at risk who are self isolated, who have themselves just lost all sense of smell (and associated taste) may unintentionally be putting others at risk.

That’s why it matters to know if those who have sufffered a recent, sudden loss of smell (and taste) but with no other symptoms are carriers of the virus and can spread not. Not good enough for Deputy CMO Jonathan Van Tam to say it’s anecdotal. Complacency costs lives