Categories
News

Rapid Covid testing in England may be scaled back over false positives – The Guardian

Senior government officials have raised “urgent” concerns about the mass expansion of rapid coronavirus testing, estimating that as few as 2% to 10% of positive results may be accurate in places with low Covid rates, such as London.

…However, leaked emails seen by the Guardian show that senior officials are now considering scaling back the widespread testing of people without symptoms, due to a growing number of false positives.

…On 9 April, the day everyone in England was able to order twice-weekly lateral flow device (LFD) tests, Dyson wrote: “As of today, someone who gets a positive LFD result in (say) London has at best a 25% chance of it being a true positive, but if it is a self-reported test potentially as low as 10% (on an optimistic assumption about specificity) or as low as 2% (on a more pessimistic assumption).”

https://www.theguardian.com/world/2021/apr/15/rapid-covid-testing-in-england-may-be-scaled-back-over-false-positives

Categories
News

More than HALF of people who test positive for Covid have no symptoms – but fatigue is still most common sign, official data shows – Daily Mail

More than half of people who test positive for Covid in the UK suffer no symptoms, official figures revealed today.

Office for National Statistics data showed 53 per cent of those diagnosed with the virus said they had no warning signs — including a fever or cough. 

https://www.dailymail.co.uk/news/article-9449319/More-HALF-people-test-positive-Covid-no-symptoms.html

Categories
Publications

Rapid, point‐of‐care antigen and molecular‐based tests for diagnosis of SARS‐CoV‐2 infection – Chochrane Library

We identified virtually no evidence for mass screening of asymptomatic individuals using rapid antigen tests in people with no known exposure. A small study screening travellers returning from high‐risk countries (Cerutti 2020), identified only five SARS‐CoV‐2 infections (prevalence of 3%) with a reported sensitivity of antigen testing for detecting infection of 40%. However, important larger studies have been published since the end of our search, as mentioned above.

https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013705.pub2/full

Categories
Publications

Clarifying the evidence on SARS-CoV-2 antigen rapid tests in public health responses to COVID-19 – The Lancet

Most people infected with SARS-CoV-2 are contagious for 4–8 days.7 Specimens are generally not found to contain culture-positive (potentially contagious) virus beyond day 9 after the onset of symptoms, with most transmission occurring before day 5. This timing fits with the observed patterns of virus transmission (usually 2 days before to 5 days after symptom onset), which led public health agencies to recommend a 10-day isolation period. The short window of transmissibility contrasts with a median 22–33 days of PCR positivity (longer with severe infections and somewhat shorter among asymptomatic individuals). This suggests that 50–75% of the time an individual is PCR positive, they are likely to be post-infectious.

https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)00425-6/fulltext

Categories
Opinion

Claim that “1 in 3 people who have the virus have no symptoms” is a massive exaggeration – Prof Fenton

Norman Fenton is Professor in Risk Information Management at Queen Mary University of London and also a Director of Agena, a company that specialises in risk management for critical systems.

One of the major messages currently being pushed everywhere by the UK Government about COVID-19 is the claim that “1 in 3 people who have the virus have no symptoms”. In fact, if we trust the Government’s own data, this claim is massively exaggerated. The true figure – as we explain below – is more like 1 in 38*. Moreover, using data from
an ongoing study at Cambridge University (in which only people without symptoms are tested) we conclude that 96% of such people who test positive do not have the virus (i.e. they are mostly false positives).

https://probabilityandlaw.blogspot.com/2021/02/claim-that-1-in-3-people-who-have-virus.html

Categories
Publications

COVID-19: management of staff and exposed patients or residents in health and social care settings – GOV.uk

Immunocompetent staff, patients and residents who have tested positive for SARS-CoV-2 by PCR should be exempt from routine re-testing by PCR or LFD antigen tests (for example, repeated whole setting screening or screening prior to hospital discharge) within a period of 90 days from their initial illness onset or test (if asymptomatic) unless they develop new COVID-19 symptoms. This is because fragments of inactive virus can be persistently detected by PCR in respiratory tract samples following infection – long after a person has completed their isolation period and is no longer infectious.

https://www.gov.uk/government/publications/covid-19-management-of-exposed-healthcare-workers-and-patients-in-hospital-settings/covid-19-management-of-exposed-healthcare-workers-and-patients-in-hospital-settings#section6

Categories
News

People with common colds testing positive for Covid-19 may simply be asymptomatic cases, experts reveal – The Telegraph

Trademark symptoms of seasonal flu could be mistaken for symptoms of Covid-19, it is claimed

People with common colds who are testing positive for Covid-19 may simply be asymptomatic cases, experts have said.

Trademark symptoms of seasonal flu could be mistaken for symptoms of Covid-19 if the individual tests positive for the virus, it is claimed.

More than eight in ten people who test positive for coronavirus show none of the main symptoms at the time they are tested, a major study by UCL previously revealed.

https://web.archive.org/web/20210109173857/https://www.telegraph.co.uk/news/2021/01/09/people-common-colds-testing-positive-covid-19-may-simply-asymptomatic/

Categories
Publications

Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China – Nature

Stringent COVID-19 control measures were imposed in Wuhan between January 23 and April 8, 2020. Estimates of the prevalence of infection following the release of restrictions could inform post-lockdown pandemic management. Here, we describe a city-wide SARS-CoV-2 nucleic acid screening programme between May 14 and June 1, 2020 in Wuhan. All city residents aged six years or older were eligible and 9,899,828 (92.9%) participated. No new symptomatic cases and 300 asymptomatic cases (detection rate 0.303/10,000, 95% CI 0.270–0.339/10,000) were identified. There were no positive tests amongst 1,174 close contacts of asymptomatic cases. 107 of 34,424 previously recovered COVID-19 patients tested positive again (re-positive rate 0.31%, 95% CI 0.423–0.574%). The prevalence of SARS-CoV-2 infection in Wuhan was therefore very low five to eight weeks after the end of lockdown.

https://www.nature.com/articles/s41467-020-19802-w

Categories
Publications

What the data say about asymptomatic COVID infections – Nature

Now, evidence suggests that about one in five infected people will experience no symptoms, and they will transmit the virus to significantly fewer people than someone with symptoms. But researchers are divided about whether asymptomatic infections are acting as a ‘silent driver’ of the pandemic.

https://web.archive.org/web/20201118211843/https://www.nature.com/articles/d41586-020-03141-3

Categories
Publications

Mass testing for covid-19 in the UK – BMJ

Spending the equivalent of 77% of the NHS annual revenue budget on an unevaluated underdesigned national programme leading to a regressive, insufficiently supported intervention—in many cases for the wrong people—cannot be defended.

https://www.bmj.com/content/371/bmj.m4436

Categories
Opinion

Covid-19: Does Sweden have herd immunity? – Sebastian Rushworth M.D.

  • Sweden never went in to full lockdown. Instead, the country imposed a partial lockdown that was almost entirely voluntary.
  • The only forcible restriction imposed by the government from the start was a requirement that people not gather in groups of more than 50 at a time.
  • People followed the voluntary restrictions pretty well at the beginning, but that they have become increasingly lax as time has gone on.
  • After an initial peak that lasted for a month or so, from March to April, visits to the Emergency Room due to covid had been declining continuously, and deaths in Sweden had dropped from over 100 a day at the peak in April, to around five per day in August.
  • Dr. Rushworth hasn’t seen a single covid patient in the Emergency Room in over two and a half months.
  • COVID has killed under 6,000 people.
  • On average, one to two people per day are dying of covid in Sweden at present, and that number continues to drop.
  • In the whole of Stockholm, a county with 2,4 million inhabitants, there are currently only 28 people being treated for covid in all the hospitals combined.
  • Sweden seemed to be developing herd immunity, in spite of the fact that only a minority had antibodies, was due to T-cells.
  • Immunity may be long lasting, and probably explains why there have only been a handful of reported cases of re-infection with covid, even though the virus has spent the last nine months bouncing around the planet infecting many millions of people.
  • Almost all cases of reinfection have been completely asymptomatic.
  • People develop a functioning immunity after the first infection, which allows them to fight off the second infection without ever developing any symptoms.
  •  England and Italy have mortality curves that are very similar to Sweden’s.
  • Lockdown only makes sense if you are willing to stay in lockdown until there is an effective vaccine.

https://sebastianrushworth.com/2020/09/19/covid-19-does-sweden-have-herd-immunity/

Categories
News Opinion

September’s normal increase in coughs and colds is causing ‘utter chaos’ in Britain because the Government has left people terrified of coronavirus, top Oxford scientist warns MPs – Prof. Carl Heneghan, Daily Mail

Professor Carl Heneghan said there has been a 50% rise in coughs and colds

This is normal for September when children go back to school and university

But Government messaging about Covid-19 has left people ‘terrified’, he said

  • A coughing illness would not normally be considered an epidemic until doctors were seeing 400 symptomatic cases per 100,000 – far higher than Covid-19 rates;
  • The Eat Out to Help Out restaurant voucher scheme likely led to an increase in the spread of coronavirus;
  • Increased testing is still only picking up a fraction of the true number of cases but it’s detecting more of ‘background’ infections because it’s more targeted, making it look like cases are soaring;
  • Bolton may be experiencing high infections because the virus was not widespread there before lockdown lifted and people did not build up any immunity;
  • Swab tests are still picking out too many people who aren’t infectious, and studying individuals’ viral loads could help officials to pick out those actually at risk of spreading it;
  • The country cannot test its way out of the outbreak and there must be a coherent strategy for what to do with knowledge of case numbers and a level that is acceptable;
  • Ambiguous phrases such as ‘Moonshot’ are not helpful for communicating the Government’s plans and have no basis in science, which should be paramount.

https://www.dailymail.co.uk/news/article-8744063/Septembers-normal-increase-coughs-colds-causing-utter-chaos-post-lockdown-Britain.html

Categories
Publications

Covid-19: the problems with case counting – BMJ

While the testing data are so opaque, using them to direct local lockdowns is unhelpful, argues Heneghan. “The testing is there to drive the test and trace strategy,” he says. “But what seems to be happening is that, as soon as we see an outbreak, there tends to be panic and over-reacting. This is a huge problem because politicians are operating in a non-evidence-based way when it comes to non-drug interventions.”

https://web.archive.org/web/20200904104824/https://www.bmj.com/content/370/bmj.m3374.full

Categories
News

CDC quietly revises coronavirus guidance to downplay importance of testing asymptomatic people – CNBC

The Centers for Disease Control and Prevention is no longer recommending testing for everyone who’s been exposed to Covid-19, saying people who don’t have symptoms “do not necessarily need a test.”

The CDC has quietly revised its guidance on coronavirus testing to say that people without symptoms who were exposed to an infected person might not need to be screened.

The agency previously recommended testing for anyone with a “recent known or suspected exposure” to the virus even if they did not have symptoms.

The CDC’s previous guidance cited “the potential for asymptomatic and pre-symptomatic transmission” as a reason why people without symptoms who were exposed to the virus be “quickly identified and tested.”

https://www.cnbc.com/2020/08/26/cdc-quietly-revises-coronavirus-guidance-to-downplay-importance-of-testing-for-asymptomatic-people.html

Categories
Publications

Diagnosing COVID-19 infection: the danger of over-reliance on positive test results – medRxiv

Unlike previous epidemics, in addressing COVID-19 nearly all international health organizations and national health ministries have treated a single positive result from a PCR-based test as confirmation of infection, even in asymptomatic persons without any history of exposure. This is based on a widespread belief that positive results in these tests are highly reliable. However, data on PCR-based tests for similar viruses show that PCR-based testing produces enough false positive results to make positive results highly unreliable over a broad range of real-world scenarios. This has clinical and case management implications, and affects an array of epidemiological statistics, including the asymptomatic ratio, prevalence, and hospitalization and death rates. Steps should be taken to raise awareness of false positives, reduce their frequency, and mitigate their effects. In the interim, positive results in asymptomatic individuals that haven’t been confirmed by a second test should be considered suspect.

https://www.medrxiv.org/content/10.1101/2020.04.26.20080911v3

Categories
News

A third of NHS staff in two hospital units were infected with coronavirus without showing symptoms, study finds – Independent

Almost 60 per cent of staff infected with coronavirus continued to work and commute

https://www.independent.co.uk/news/health/coronavirus-nhs-staff-symptoms-antibodies-covid-maternity-test-a9664841.html

Categories
Opinion

Our government should not be copying totalitarian states – Dr. John Lee, Spiked

  • The government is purporting to engage with ‘The Science’, but it is also engaging in psychological operations.
  • But a side-effect of compelling people to wear masks is that some may decide it is all too stupid, and they are not going to go to the shops until this idiocy is over.
  • But a side-effect of compelling people to wear masks is that some may decide it is all too stupid, and they are not going to go to the shops until this idiocy is over.
  • The science on masks is very weak. The claim is that you might spread Covid-19 without knowing, if you have it asymptomatically.
  • Firstly, asymptomatic Covid-19 spreading around is good because it reduces the virulence of the virus.
  • Secondly, the idea that masks stop the spread is not only totally unproven, but also facile. It is a failure of imagination.
  • When a droplet hits a mask, it will dry out within seconds or, at most, minutes. If there is any substance to the droplet other than water, it will turn into a dust particle. Unless you superglue the mask to your face, there will be a constant rain of dust particles coming out from all directions around your mask as you breathe. They will be breathed in by others and the virus will do what it does.
  • There seems to have been no assessment whatsoever of the effects of lockdown before we entered it. That violates a key principle of medicine: first, do no harm. 
  • There is a term in medicine for taking action without that knowledge: negligence. The government was negligent in putting us into lockdown with no assessment of what that would do.
  • The most common symptoms of Covid-19 are not fever, cough, headache and respiratory symptoms – they are no symptoms at all, and around 99 per cent of those who catch this virus recover.
  • The government painted itself into a corner very quickly. It doesn’t know how to get out of that corner apart from by acting out the scenario that it came up with in the first place, which is why, months after we could have abolished all these restrictions and got back to normal, we are going through more months of public virtue-signalling and ritualistic behaviour. 
  • The WHO is not fit for purpose and whose performance has been lamentable
  • The WHO said there were no asymptomatic cases of Covid-19. Now, it is reckoned probably about 90 per cent of people who get Covid-19 are asymptomatic. That is a big change in viewpoint.
  • Broadcasters have done a woeful job of presenting balance on this, and have not allowed views contrary to the mainstream narrative to reach the public.
  • I also fear too many people are compliant, and complacent in thinking the government knows what it’s doing.
  • This episode is showing us that personal freedom must not be taken for granted.

https://www.spiked-online.com/2020/08/07/our-government-should-not-be-copying-totalitarian-states/

Categories
Opinion

Coronavirus: Why everyone was wrong – Dr. Beda Stadler

Professor Dr. Beda M Stadler is the former director of the Institute for Immunology at the University of Bern, a biologist and professor emeritus.

Novelty:

Sars-Cov-2 isn’t all that new, but merely a seasonal cold virus that mutated and disappears in summer, as all cold viri do — which is what we’re observing globally right now. Flu viri mutate significantly more, by the way, and nobody would ever claim that a new flu virus strain was completely novel.

Immunity:

In mid-April work was published by the group of Andreas Thiel at the Charité Berlin. A paper with 30 authors, amongst them the virologist Christian Drosten. It showed that in 34 % of people in Berlin who had never been in contact with the Sars-CoV-2 virus showed nonetheless T-cell immunity against it (T-cell immunity is a different kind of immune reaction, see below). This means that our T-cells, i.e. white blood cells, detect common structures appearing on Sars-CoV-2 and regular cold viri and therefore combat both of them.

…almost no children under ten years old got sick, everyone should have made the argument that children clearly have to be immune. For every other disease that doesn’t afflict a certain group of people, we would come to the conclusion that that group is immune. When people are sadly dying in a retirement home, but in the same place other pensioners with the same risk factors are left entirely unharmed, we should also conclude that they were presumably immune.

Modelling:

Epidemiologist also fell for the myth that there was no immunity in the population. They also didn’t want to believe that coronaviri were seasonal cold viri that would disappear in summer. Otherwise their curve models would have looked differently. When the initial worst case scenarios didn’t come true anywhere, some now still cling to models predicting a second wave.

Asymptomatic transmission:

The term “silent carriers” was conjured out of a hat and it was claimed that one could be sick without having symptoms.

The next joke that some virologists shared was the claim that those who were sick without symptoms could still spread the virus to other people…But for doctors and virologists to twist this into a story of “healthy” sick people, which stokes panic and was often given as a reason for stricter lockdown measures, just shows how bad the joke really is. At least the WHO didn’t accept the claim of asymptomatic infections and even challenges this claim on its website.

Testing:

So if we do a PCR corona test on an immune person, it is not a virus that is detected, but a small shattered part of the viral genome. The test comes back positive for as long as there are tiny shattered parts of the virus left. Correct: Even if the infectious viri are long dead, a corona test can come back positive, because the PCR method multiplies even a tiny fraction of the viral genetic material enough [to be detected]…The crux was that the virus debris registered with the overly sensitive test and therefore came back as “positive”. It is likely that a large number of the daily reported infection numbers are purely due to viral debris.

Kawasaki Syndrome:

If an infected person does not have enough antibodies, i.e. a weak immune response, the virus slowly spreads out across the entire body. Now that there are not enough antibodies, there is only the second, supporting leg of our immune response left: The T-cells beginn to attack the virus-infested cells all over the body. This can lead to an exaggerated immune response, basically to a massive slaughter; this is called a Cytokine Storm. Very rarely this can also happen in small children, in that case called Kawasaki Syndrome. This very rare occurrence in children was also used in our country to stoke panic. It’s interesting, however, that this syndrome is very easily cured. The [affected] children get antibodies from healthy blood donors, i.e. people who went through coronavirus colds.

Second Wave:

The virus is gone for now. It will probably come back in winter, but it won’t be a second wave, but just a cold.

Face masks:

Those young and healthy people who currently walk around with a mask on their faces would be better off wearing a helmet instead, because the risk of something falling on their head is greater than that of getting a serious case of Covid-19.

Lethality:

People below 65 years old make up only 0.6 to 2.6 % of all fatal Covid cases. To get on top of the pandemic, we need a strategy merely concentrating on the protection of at-risk people over 65.

https://medium.com/@vernunftundrichtigkeit/coronavirus-why-everyone-was-wrong-fce6db5ba809

Categories
Publications

80.9% of care home residents who tested positive were asymptomatic – Department of Health & Social Care

  • 2.4% of all tests were positive (9,674 out of 397,197)
  • 3.9% of residents tested positive (6,747 out of 172,066)
  • 3.3% of asymptomatic residents tested positive (5,455 out of 163,945)
  • 80.9% of residents who tested positive were asymptomatic (5,455 out of 6,747)
  • 1.2% of asymptomatic staff tested positive (2,567 out of 210,620)

https://www.gov.uk/government/publications/vivaldi-1-coronavirus-covid-19-care-homes-study-report/vivaldi-1-covid-19-care-homes-study-report

Categories
Publications

Comparative community burden and severity of seasonal and pandemic influenza: results of the Flu Watch cohort study – The Lancet (2014)

Most Flu Is Asymptomatic

On average, roughly 20% of the unvaccinated had serologic evidence of influenza infection, but up to three quarters of the infected were asymptomatic. The proportions did not vary significantly between seasonal and pandemic influenzas. The pandemic H1N1 strain was associated with less severe symptoms than the seasonal H3N2 strain.

NEJM Journal Watch, 17 March 2014

https://www.thelancet.com/journals/lanres/article/PIIS2213-2600(14)70034-7/fulltext