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18 May 2020 18:43

Coronavirus Olfaction Van der Valk

Tens of thousands of cases of Covid-19 may have been missed because of delays in warning the public that loss of taste and smell is a key symptom that should lead to self-isolation or testing, experts say. The four chief medical officers of the UK have finally made official what many scientists had been saying for weeks: that anosmia, or loss of smell, should be added to the other two main warning symptoms, a continuous cough and high temperature. Prof Tim Spector from King's College London and his team said data from 1.5 million people who downloaded their symptom-reporting app suggested 50,000 to 70,000 people in the UK had been missed. As early as 1 April, they warned that people with anosmia should self-isolate. They were joined by ear, nose and throat surgeons, who said loss of taste and smell could be one of the few markers for people who were otherwise asymptomatic and potentially able to infect other people without realising they were a risk.

Covid-19: why are some people losing their taste and smell? Their professional body, ENT-UK, said they had been calling for eight weeks for anosmia to be listed as a marker for asymptomatic carriers. "We estimate that many hundreds of thousands of patients in the UK have developed anosmia as a result of Covid-19," said Prof Claire Hopkins, the BRS president. Speaking on BBC radio hours before the announcement by the four CMOs of the change of guidance, Spector said the UK was out of step with other countries. He also said that anosmia was only one of 14 symptoms reported by the app users that could serve as warning signs.

"[The app] tells us that we've got at least 100,000 cases at the moment of people who are infected and this is from our data, although the NHS would underestimate that because they're not counting all the symptoms. We list about 14 symptoms which we know are related to having a positive swab test, and these are not being picked up by the NHS." Between 24 and 29 March, data from the app showed that 59% of users who tested positive for Covid-19 experienced loss of smell and taste compared with 18% of those who tested negative. They were three times more likely to have contracted Covid-19 and should self-isolate to reduce the spread of disease, the team said on 1 April. Spector said 17 other countries including the US had altered their list of symptoms, but not the UK. "At the moment, people are being told to go back to work if they're a care worker, and they've got something like loss of smell or taste or severe muscle pains or fatigue – things that we know and we've shown are related to being swabbed positive," he said. "This country is missing the ball in underestimated cases but also putting people at risk, and continuing the epidemic. So we really do need to tell Public Health England to get in line with the rest of the world, and make people more aware. "The announcement that the CMOs have now recognised smell and taste disturbances is extremely welcome, albeit much later than other European counterparts and at least two weeks after the WHO added it to their list," said Carl Philpott, a professor of rhinology and olfactology at Norwich Medical School, UEA. Show Hide The World Health Organization (WHO) guidance on face masks has remained consistent during the coronavirus pandemic. It has stuck to the line that masks are for healthcare workers – not the public. "Wearing a medical mask is one of the prevention measures that can limit the spread of certain respiratory viral diseases, including Covid-19. Nevertheless, as some countries have eased lockdown conditions, they have been making it mandatory to wear face coverings outside, as a way of trying to inhibit spread of the virus. This is in the belief that the face covering will prevent people who cough and sneeze ejecting the virus any great distance. There is no robust scientific evidence – in the form of trials – that ordinary masks block the virus from infecting people who wear them. There is also concerns the public will not understand how to use a mask properly, and may get infected if they come into contact with the virus when they take it off and then touch their faces. Also underlying the WHO's concerns is the shortage of high-quality protective masks for frontline healthcare workers. Nevertheless, masks do have a role when used by people who are already infected. Given that many people with Covid-19 do not show any symptoms for the first days after they are infected, masks clearly have a potential role to play, especially on crowded public transport as people return to work.. This is particularly pertinent in healthcare workers where reports of smell and taste disturbances have been commonplace, meaning the transfer of infection from colleagues to each other and to uninfected patients will have been happening unchecked." England's deputy chief medical officer Jonathan Van-Tam said the government's new and emerging respiratory virus threats advisory group (Nervtag) began looking at the data on 27 March. Van-Tam said the data had been kept under regular review but there were questions as to how significant the symptom was. Van-Tam said they did not know how many people experienced this symptom, nor whether it was more common in some groups than others. "We have seen some signalling in some of the literature that anosmia may be more frequent in females," he said. "Clearly we are moving into a period, thankfully, where we have much lower disease activity in the UK," said Van-Tam. He acknowledged that the three symptoms were not the only ones, but said fatigue and muscle pains, for instance, were too common to be included as triggers for tests at this point. The Government has today announced that anyone with symptoms of coronavirus is now eligible to book a test, ahead of the rollout of the test and trace service. The expansion in testing eligibility comes after all four UK Chief Medical Officers confirmed that anosmia has been added as a symptom of COVID-19. Anosmia is the loss of or a change in your normal sense of smell, and it can also affect your sense of taste. This means people should self-isolate immediately if they have a new, continuous cough; high temperature; or a loss of or change in their normal sense of smell or taste. The extension in testing eligibility comes ahead of the rollout of the new test and trace service and is possible thanks to increased testing capacity across the country as the Government expands total testing capacity towards 200,000 tests a day. "This is a huge step forward in our plan to slow the spread of the virus, protect the NHS and give the peace of mind these tests can bring. "We will continue to give priority for NHS staff and care home residents and workers in order to protect our most vulnerable." The tracing element of the service in England, due to be launched shortly, will be supported by 21,000 contact tracers who have now been recruited, and will play a vital role working to reach those who have been in close contact with someone who has developed coronavirus. The new workforce in England of more than 21,000 contract tracers will be overseen by experts from Public Health England and local government. "We have seen a fantastic response to join the virtual frontline of home-based Clinical Contact Caseworkers for the test and trace service.