The video explores the challenges and implications of the PCR testing method for detecting COVID-19, specifically focusing on false positives. In Aberdeen, lockdowns have been reimposed, and similar scenarios have surfaced across other regions, raising concerns about the reliability of these tests. The PCR test can detect virus fragments from past infections, potentially leading to false positives and subsequent decisions being made based on inaccurate data. Experts discuss the relevance of these tests in monitoring the virus within communities.

Despite concerns, some professionals in the medical community affirm the importance of positive cases for understanding the virus's spread. While false positives can skew statistics, they are seen as a minor issue in the overall picture. Professionals highlight that interpreting positive results requires caution, especially when these results are used to drive policy decisions. Regular quality control is suggested to ensure consistency, and it remains crucial to respond swiftly to any spikes in detected cases to avoid larger outbreaks.

Main takeaways from the video:

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Key Vocabularies and Common Phrases:

1. reimpose [ˌriːɪmˈpoʊz] - (verb) - To impose again after having been removed or relaxed. - Synonyms: (reinstate, reestablish, restore)

Today in Aberdeen, lockdown restrictions have been reimposed due to a virus cluster in the city.

2. puzzled [ˈpʌzəld] - (adjective) - Confused because something is difficult to understand. - Synonyms: (bewildered, perplexed, confused)

In Leicester, where strict lockdown was imposed at the end of June, doctors and local leaders were puzzled.

3. judiciously [dʒuˈdɪʃəsli] - (adverb) - With good judgment or sense. - Synonyms: (wisely, prudently, sensibly)

BCR is a very, very good instrument, but it has to be used judiciously.

4. rigorous [ˈrɪɡərəs] - (adjective) - Extremely thorough and careful. - Synonyms: (meticulous, thorough, stringent)

Public Health England says it's hard to rigorously establish false positives.

5. advancing [ədˈvænsɪŋ] - (verb) - Moving forward in a purposeful way. - Synonyms: (progressing, moving forward, developing)

This is the only yardstick by which we can assess how the pandemic is advancing across the world.

6. yardstick [ˈjɑːrdˌstɪk] - (noun) - A standard for making a judgment or comparison. - Synonyms: (benchmark, standard, criterion)

This is the only yardstick by which we can assess how the pandemic is advancing across the world.

7. trajectory [trəˈdʒɛktəri] - (noun) - The path followed by a projectile or an object moving under given forces. - Synonyms: (course, path, route)

Surely that is a good indicator of the trajectory of the virus.

8. consequences [ˈkɑːnsəˌkwɛnsɪz] - (noun) - A result or effect of an action or condition. - Synonyms: (result, outcome, effect)

But right now we're dealing with the aftermath and that is causing just as much harm as the virus itself.

9. collateral damage [kəˌlætərəl ˈdæmɪdʒ] - (noun) - Unintended damage or impact occurring as a result of a legal or social action. - Synonyms: (unintended consequences, side effect, byproduct)

The unintended consequence of an excessive focus on Covid.

10. stagger [ˈstæɡər] - (verb) - To walk or move unsteadily; to arrange events, payments, hours, etc., so that they are not at the same time. - Synonyms: (stumble, falter, wobble)

If we're locking down entire regions and entire cities on the basis of a test which has not been validated at this stage, this is very troubling.

How accurate are coronavirus tests? - BBC Newsnight

Across the UK, big decisions are being made based on the numbers. Testing positive for coronavirus infection. Today in Aberdeen, lockdown restrictions have been reimposed due to a virus cluster in the city. In Leicester, where strict lockdown was imposed at the end of June, doctors and local leaders were puzzled. Positive cases had increased. Get good results. Hospital admissions had not gone up and nor, thankfully, had deaths. It's difficult to know why, and various theories circulated. One of the reasons, they told us, was the test could be producing false positives. The test used to detect positive cases is called PCR, and it only requires very small samples to see if there's any virus present.

Now, PCR doesn't tell you if what it detects is infectious. It may pick up on virus fragments from a past infection that isn't currently making you sick. Now, this means there could be false positives, so there's a positive test result, but no active infection. It's tools, you go and use them. Tom Jefferson is a World Health Organization advisor. He's looked at these PCR tests and found there was a lack of good evidence about their usefulness and reliability in picking up infectious people. If the virus is no longer circulating at high levels and you go looking for it with an uncertain cutoff, and you go testing lots of people, you will find remnants of it, you will find some positives, but as there are remnants of the virus, of viral particles they are not capable of replicating, you are not infected and you are infectious, but classified as such. So we have to be very careful.

BCR is a very, very good instrument, but it has to be used judiciously. It's accepted that if you test more, you're likely to find more cases. And in recent weeks, we've been carrying out a lot more tests across England. But if you look at the percentage of those tests that are positive, it tells an interesting story. There are small fluctuations, but the proportion of tests producing positive results stays pretty flat and it's always below 1%. The government's own documents acknowledge. When only a small proportion of people being tested have the virus, the operational false positive rate becomes very important. Despite this, the government also acknowledges there are no published studies on the operational false positive rate of any national Covid-19 testing program.

So false positives can have a big impact. When there are low levels of virus circulating, so say a test produces 0.5% false positives doesn't sound much, but say you test 1000 people and only one of them are infected with coronavirus, the test may or may not pick up that person and it will also produce five false positive results. Public Health England says it's hard to rigorously establish false positives, but they do evaluate tests. Labs have guidance and they say that they think around one to 2% of false positives. But some doctors are worried. The scale of testing is now massive, and that's set against the situation of a declining rate of infection. And all of these really set the ideal conditions for false positives and potentially really quite poor decision making.

On the back of these false positives, we're taking massive decisions. I mean, if we're locking down entire regions and entire cities on the basis of a test which has not been validated at this stage, this is very troubling. Not everyone shares these concerns. Positive cases, they say, are the only way of knowing how much virus is in the community. You might be finding bits of virus that are not infectious late, after somebody's been infected and they've got better. That's going to be a very small proportion of the total number of cases, not a significant number. That's going to skew the statistics in any bad sort of way. We have to bear in that in mind when you're interpreting the results, as long as you know about that, when you're interpreting results, it's not really a big problem at all. Like so often with COVID, we are learning all the time, and that includes how we interpret positive test results in different settings.

Deb Scomo joining me now, doctor David Navarro, who is the special envoy on Covid-19 for the World Health Organization, and doctor Ron Daniels, an ICU consultant at Birmingham Central Hospital. Good evening to both of you. First of all, I want to put the same question to each of you. Let's deal with this test for infection, the PCR. I want to ask you if you think it's reliable enough, Doctor Daniels. So the first thing to say is, I'm an NHS clinician at the coalface and I'm not a testing expert, but we do see and we've got experience with these PCR tests for many, many years, and the reality is we always take the results with a little bit of a pinch of salt. So if we're doing a PCR test for a particular bacteria, if the patient doesn't have the symptoms of infection, we won't start antibiotics, and that's the concern here. I think the analogy that you gave of you test 1000 people, one of whom is positive, but the test will pick up six people. If it's got a 0.5% false positive rate, that's significant if it's being used to drive policy decisions.

Well, Doctor Nabara, is it a problem, the reliability of the test for you, do you think? Personally, I don't think so. I'd really like to stress to everybody that the reverse transcriptase PCR test is the gold standard that we use for picking up people who have got the COVID in their systems. And in fact, usually we're more concerned about what we call false negatives. That's people who've got Covid but end up with negative tests, perhaps because of the way in which the sample was taken. And in general, there is a feeling that in some settings the false negative level can be quite high. Second quick point is that what actually tends to happen when you get a spike of COVID building up, you get a relatively small number of people turning up with positive results. But you have to take that seriously, because the way in which the infections build up is that they grow terribly rapidly. And so when you see a small spike, you have to act quickly so as to prevent a large surge of infection building up and then bringing people into the hospital.

But if we are trying to get an overall picture, is it fair to say that some labs have a different standard? And I don't just mean nationally, I mean internationally, on interpreting these PCR tests, some are more sensitive than others. Well, but I think that in general, the quality control of PCR testing has been really quite good. Of course, the World Health Organization works with the manufacturers from all over the world trying to make sure that things are standard. And occasionally there are kits used for the PCR test that are found to be unreliable and then fairly quickly and an effort is made to make sure they're not used. We put an awful lot of effort into this because this is the only yardstick by which we can assess how the pandemic is advancing across the world.

But you could. Sorry, just. Just picking up on Deb's point, but you could perhaps be picking up old, tiny bits of infection or pieces of virus that are not infected at all. This was a concern. For example, in South Korea, it was found that there were people who were being found positive and then they were treated and then they were found to be positive again. The question was, were they being reinfected? Were these particles of virus that were being picked up? And the second feeling in the end was that it was particles. But by and large, this issue of the test picking up people who've got bits of virus that are not really fully infectious, this is not a major concern from our perspective. So Doctor Daniels, let's come on to your daily experience of COVID for example. I mean, today, what was your experience today in the hospital?

So I've been working over the last several days across two large hospitals in central Birmingham. I've also spoken to colleagues in areas of Birmingham that have been hit with these outbreaks that we've been seeing. And I absolutely agree that testing is the right way to monitor for outbreaks. It just might give a slightly skewed picture as we enhance the number of tests in terms of the national number of cases. But in Birmingham right now, across the hospitals I've spoken to, that covers well over 50% of Birmingham's population. We have less than 20 cases currently seriously ill and fewer than ten cases currently critically ill. Compare that to where we were a couple of months ago, where we had almost 200 patients ventilated at any one given time, and this is a huge downturn.

Seen the same in other countries? Yes, particularly in Spain. We've got a high level of infection with the lowest level of people in hospital. So does that lead you to think that actually our judgments about the progression of COVID should be made on the number of cases that are hospitalized, rather than the number of people who are testing positive for the virus out in the wider world? Well, I think we've got to look at both together. Together with the proportion of tests carried out that have been positive, we've got to look at all of the data rather than any one data dataset in isolation. We've moved from, of course, flattening the curve to protect our healthcare systems to controlling the virus. But what we can't do is to make that move and consider the two entities completely in isolation.

Our NHS within the UK right now is filling back up with the normal caseload that we would see at this time of year, we're seeing very few admissions with people with coronavirus. And that's true whether in Birmingham, whether in Swindon, whether we're in reading. It is simply the case that although we're testing more and identifying more cases, our hospitals are not yet. And the experience in Spain and France, they've had a couple of weeks ahead of us in terms of an increase in number of cases. Their hospitals are also not yet filling up with sick people. So, David Navarro, if we're consistently having lower admissions to hospital with coronavirus, surely that is a good indicator of the trajectory of the virus.

Well, Kirsty, while you were asking Doctor Daniels, I was just thinking, isn't that great news? Because it's wonderful if we are able to move to a situation where, although there's still quite a lot of COVID circulating and we're trying to get a handle on that in communities, there are not lots of really sick people coming to hospitals. That's such good news. It almost certainly means that we're getting much better detecting people with the virus quickly and bringing those under treatment if they need it rapidly. It also means that we may well be in a situation where we're moving ahead of the virus, which is where we in the World Health Organization want the whole world to be. We want to get to a situation where economies can get going, people, kids can get back to school, health services can function normally despite the fact that we've got this virus sticking around as a constant threat.

And this is the, for me at least, moving towards the ideal situation where we will be able to live with the COVID and get on with the rest of life. So therefore this might seem an extraordinary thing to finish with. But I wonder if you might think, Doctor Daniels, that at this stage, given what else is going on with other ailments in society, with cancer, with all sorts of things, that now we are making too big a deal of the coronavirus. Well, I think we're looking at the national number of cases with a bit too much vigor.

I think we need to look at it balanced against the other data we have, including hospital admissions and critical care admissions. And of course deaths, which again are every death is a tragedy, but they're very much lower than they were. We have to remember the knock on effects of this virus. We're seeing a lot of people with mental health issues who are becoming very unwell, either through self neglect, through anxiety and fear I. Or through self harm. There's the cancer issue. There are people presenting late with heart attacks and strokes. The unintended consequence of an excessive focus on Covid. And don't get me wrong, during the height of this crisis and we hope we don't get there again in the winter. This was horrible in british hospitals. But right now we're dealing with the aftermath and that is causing just as much harm as the virus itself. Thank you both very much indeed.

Health, Covid-19, Pcr Testing, Technology, Science, Leadership, Bbc Newsnight