Why I trust Lateral Flow Tests
When I had Covid, they were remarkably accurate
The latest Covid conundrum is why so many people seem to be currently testing positive on their instant Lateral Flow Test and then test negative when they take their PCR. Tom Chivers unpacked the maths on these pages earlier this week, and Dr Oliver Johnson has confirmed in an excellent Twitter thread that the disparity between the testing methods seems to be widening recently.
I’ll leave the probability calculations to superior brains, but I wanted to throw in one piece of anecdotal evidence that I don’t feel gets talked about enough. (To repeat: I am aware this is anecdotal!)
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I had Covid back at the start of August — for the first time as far as I know, and after two Pfizer vaccinations. It was hardly the worst week of my life (I watched the entirety of Call my Agent, which was a saving grace) but I was ill enough to feel somewhat shortchanged by Messrs Pfizer and BioNtech. I had all the classic symptoms — loss of taste and smell, high fever, fatigue etc — and it felt pretty much how I would expect it to feel in an otherwise healthy 39 year old.
Anyway, I took a lateral flow test every day of the experience. The photographic record of them is above. Notice how the first positive test was just a faint little second line, and then, as I became more sick, it got darker and darker. The worst days roughly correlated with the darkest lines. As I got better, the second line got thinner and thinner, until eventually — finally! — I started testing negative, as I have ever since.
Over the course of the past two years I reckon I have taken over a hundred LFTs. There was a period when we were doing them every day in the office. At one point in this strange era, people made guests do them upon arrival at dinner parties. Every time I took a plane, or had any kind of cold symptoms, I would be doing LFTs.
I have never, not once, had anything even half-suspiciously looking like a second line except when I had Covid; furthermore the perfect increase of the strength of that second line as I got more sick, up to a peak, and gradually back down to nothing, suggests to me that the tests are extraordinarily accurate. There was no noise, no real jumps backwards and forwards. Others who have had Covid or who have been testing their children report the same gradual increase and decrease. If they were such sketchy, rough and ready tests, it feels like this would not be happening?
So since my Covid experience I have a newfound respect for the accuracy of these little Chinese-made devices. We may all abhor them by now, and the hideous swabbing experience that goes along with them, but it seems hard to deny that they are highly clever — and highly accurate.
(Incidentally, this accuracy makes a mockery of the obsession with vaccine passports. Now that we know how easy it is to get, carry and pass on Delta Covid post vaccination, if you did have a scenario that you were very anxious to keep Covid-free — a wedding with lots of oldies, for example, or a hospital ward — it would surely be much safer to test everyone with LFTs on arrival than ask people for vaccine status?)
For me, the key takeaway from this article is we’re all likely to assess covid-related issues based on our personal experience.
For almost two years now we’ve watched the politicization of the pandemic, health experts selectively present the facts to further a particular agenda, scientists cancel one another for holding the wrong opinion about covid and lockdowns, and, most recently, the US president publicly disagreeing with his own experts regarding the timing/desirability of a covid booster shot.
The logical response to this chaos is to follow your own judgment and that will largely be based on personal experience and the experiences of relatives and friends.
Sad when you think how much money taxpayers give to experts, health organizations and politicians who are supposed to advise us on these matters.
Very insightful. Thank you.
I call this empirical evidence rather than personal experience. It is a reality check that you aren’t being lied to. I’m a department head at a large industrial facility. Every morning since this nonsense began we have been going over Covid tracking of our employees. At this point in time roughly a quarter of our employees have tested PCR positive for Covid over these 18 months. Out of roughly 500 employees 2 have gotten sick enough to go to be hospitalized and one of them died. One was our oldest employee who was 71 at the time. He was dehydrated and needed IV for a couple days. He is actually back working. He likes working and doesn’t want to retire. The employee who died had experienced two heart attacks previously and wasn’t in the best of health. All other employees who have gotten sick have fully recovered and are back at work.. well minus the 5 who are currently PCR positive who are out quarantining. I have not seen a case of “long” covid at this facility. This appears to be a giant racketeering operation as best as I can tell.
Hmm, two hospitalised and one dead out of 500 is pretty high compared to other risks, which we take seriously in society. It also ignores the fact that presumably most of your employees have not become infected at all; had they done so more might well have become ill.
Too many people on here have gone from justified scepticism about the government’s approach to controlling covid, to outright denial that it is a concern at all. Well, perhaps we should not care about a highly infectious disease, but then I would say, be consistent and stop purporting concern over cancer or any other disease!
1 in 500 over 18 months in what sounds like an industry whose demographic covers post retirement ages does not sound high. UK population is 64million and every year half a million die so we are heading towards a million for this pandemic duration. That’s 1 in 64 for the UK and 1 in 500 for his company. If you want to start breaking this down to make your point then carry on BUT the high level numbers indicate this is absolutely NOT the deadly plague like disease we have been brainwashed into believing. It can be compared to a bad flu but no more serious than that.
Incidentally, this accuracy makes a mockery of the obsession with vaccine passports.
What makes a mockery of the obsession with vaccine passports is the fact you’d been vaccinated.
I know right?! Unherd has been a place I imagined I was going to escape the covid craze, Freddy has been vaccinated and obsessively used a LFT?!
His ignorant article on psychology was bad enough but this is me over and out.
No need to be offensive – unless it’s just that you’re an offensive person.
I suspect Freddy’s a ‘generalist’.
Seems to me that the most interesting thing regarding Freddie’s anecdote is that he caught COVID following FULL vaccination. This is especially noteworthy as Freddie is just not some unknown person somewhere in some statistic, but somebody who the readers of Unherd actually know, albeit virtually from his superb interviews. But isn’t Freddie a little curious as to how he actually caught COVID despite being doubly vaccinated. What sort of highly crowded, poorly ventilated space did Freddie wonder into. Doesn’t Freddie wonder whether the Pfizer vaccine and for that matter all the rest that make the spike protein either from RNA or DNA is vastly less effective than advertised. Does he not wonder that maybe one of the reasons is that there is a big gap between the RNA and DNA vaccines and the produced spike protein: i.e. there could be an order of magnitude or more person to person variation in the amount of spike protein actually produced. After all, in a regular vaccine you know exactly how much antigen you are injecting into the patient; for the RNA and DNA vaccines you have no clue as to what the variation in amount of spike protein produced actually is. It would not be surprising, for example that the transcriptional (for DNA vaccines) and translational (for DNA and RNA vaccines) efficiency varies dramatically with age which is why it may be less effective for the very demographic who are most at risk of bad consequences of a COVID infection.
Yes, it’s remarkable how the vaccinated are able to ignore the conundrum of still being able or even actually catching the disease, in a noticeable and unpleasant way. This is not what we have been accustomed to consider ‘vaccination’.
a friend of mine, double vaccinated for some months, had to go to hospital for an unrelated test procedure. They required her to have a laboratory COVID test before the procedure, she had to produce the results before being accepted on the day She asked the nurse, totally politely, why she needed this as she was double vaccinated. Basically the nurse admitted that the vaccine was not reliable enough .
she was also asked to self isolate in between the test and her arrival at the hospital, about thirty six hours. ‘Well,I can isolate at home, but I have to get to the hospital by bus, train and Tube ( it is 80 miles away, in Central London, with absolutely no parking). The nurse just laughed ‘ it’s nonsense, isn’t it,’ she said. ‘ Don’t worry’.
i feel we should have a different term for COVID vaccination. It just doesn’t fit the established definition at all.
Immediately thought the same thing. Looks to me that this healthy thirty nine year old’s virus was injected into his system (second time’s the charm?). I’m 24 years older than him, no jab, no mask, living in densely populated area in the US, and haven’t had so much as a sniffle.
“To sustain the funding base beyond the crisis, he said, we need to increase public understanding of the need for MCMs such as a pan-influenza or pan-coronavirus vaccine. A key driver is the media, and the economics follow the hype. We need to use that hype to our advantage to get to the real issues. Investors will respond if they see profit at the end of process, Daszak stated.”
In paragraph titled “Lack of Public Understanding of Threats”2016… this thing has been in the works for a long time.
Yes, an anecdote isn’t data.
indeed it begs the question, if Freddie had not been vaccinated what would he have experienced anyway as a healthy 39 year old?We have always understood that the vaccines don’t stop you getting covid but reduce greatly your chances of hospitalisation and death, apparently confirmed by recently published studies according to French radio. But as it’s the old and vulnerable who by far have the worst experiences of covid, is there any real evidence that the vaccines make any difference to the younger fit and healthy population? My own experience of covid back in April 2020 (self diagnosed with hindsight) was a few days of headaches, (which I never get) feeling a bit tired for few weeks and a strange minuscule capillary blood clot in a toe which took a year to grow out. The whole experience was so mild I wouldn’t have thought much of it, and certainly wouldn’t have consulted a doctor.
Interestingly, the second Pfizer shot produced the same headaches but more severe tiredness for 2 days which reminded me precisely of my ‘real’ dose of covid.
I have also thought that vaccine passports for covid are hard to justify as a public health measure, as well as odious and divisive, as the vaccines do not prevent infection and transmission.
No one has ever claimed that vaccination is 100% effective! Seems a lot of people on here struggle with the concept of ‘more’ or ‘less’. It is all black and white.
Johann never claimed it was 100% effective. His analysis of the antigen response is entirely correct. What does not get mentioned in the mainstream press is that the spike protein is biologically active, oops. In other words the “vaccine” is getting your ribosomes to manufacture a poison……nice one! Not only that but this vaccine does not stay near the injection site but circulates around the body.
“Over the course of the past two years I reckon I have taken literally hundreds of LFTs. ”
Huh? Didn’t they come out just “a few” months ago?
Anyway, I am not sure of what your point is. Are you saying that vaccines are a waste of time, let alone vaccine passports?
Moreover, what additional knowledge did you gain by doing all those tests? Wouldn’t you have stayed at home anyway when you fell ill? Would it have made any difference at all had you had exactly zero tests done?
I too was surprised at “ hundreds of LFTs …..” The thought of Freddy/ anybody gagging hundreds of times is quite funny. Why self inflict this torture? Perhaps it’s goes with the job of journalism.
I have literally done it twice. Once to watch the Wimbledon, the other to go to theatre, have come up negative & am not vaccinated. If I do get the disease, I’ll deal with it.
I think in some jobs and some circumstances daily tests are done.
In frontline medicine maybe, but scribbling?
If taking a Covid test is your idea of torture then I suggest you’re a bit soft!
Come on guys. Vaccines have prevented hospitalisation and death big time. On the ground in general practice despite covid prevalence clinically it’s a very different beast now.
LOL. Sure. “To sustain the funding base beyond the crisis, he said, we need to increase public understanding of the need for MCMs such as a pan-influenza or pan-coronavirus vaccine. A key driver is the media, and the economics follow the hype. We need to use that hype to our advantage to get to the real issues. Investors will respond if they see profit at the end of process, Daszak stated.”
In paragraph titled “Lack of Public Understanding of Threats”2016… this thing has been in the works for a long time.
Well I do agree that the vaccines have been way over-hyped and have under delivered. Remember those few months ago where countries were going to wipe out Covid from planet earth? Pffft.
When Fuhrer Johnson U-turned after 3 days on everything he’d said in the first COVID-19 press conference with Unbalanced Vallance and Dim Whitty, he initiated a global psychotic break.
We don’t use these in darkest Africa I don’t think. Do they have dates on them? (Thinking I’ll just keep a handy negative one in my pocket).
They don’t have dates – but the result they display can decay a few hours after one completes the test. You’re suposed to ready the result close to exactly 30 mins after finishing the previous step. When folk take one shortly before an event, its common to take a pic on ones phone.
They to have unique QR codes & ID numbers, so re-using the same pic might be detectable. And some would see it as fradulent, to put in mildly.
I have gotten to the point where I would consider fraud. What has happened to common sense? If I am sick, I stay at home. If I cough or sneeze, I don’t do it in someone’s face. Time to get back to normal life.
Lesley, I thought you were one of us troopers, and when you felt:
“If I am sick, I stay at home.”
You set the stopper on the horse de-wormer tube and take a slug like I/We do.
Anyway, Freddie’s post shows up the craziness of it all. That recovery from the virus is not counted on proposed Virus Passports shows clearly that none of this is anything to do with health. That the double vax does not stop infection makes it all even madder.
P.S. once after seeing my doctor for a scheduled check up I asked him how he thought of Ivermectin and he said something vague about some interesting studies…and then I asked him about taking the horse de-wormer, and he said it is exactly the same medicine as humans take and showed me the door…..which made me feel good about the 4 tubes I have in my medicine cabinet.
Maybe I should rephrase. In the days prior the great reset (i.e. prior 2020), if we were sick we went to work. Now we stay at home and take Ivermectin. Especially as the new anti-viral ‘fairy dust’ drug from Merck costs $700 for a course.
I’d agree that in many places the rules seem tpo restrictive. Just mentioned the fraud angle as wanted to give a compehensive answer.
Pharmaceuticals are raking in billions with the help of government mandates. Instead of money going toward these and vaccine passport technology, I would rather see healthcare systems improve and better pay for staff.
All days used to be good days for Big Pharma. These days they are like pigs rolling in ……
So, it turns out that LFTs have shown that when we have symptoms we are ill and when we don’t have symptoms we are not ill.
Blimey! This could herald in a whole new era of diagnostics.
Oh, wait a minute, it all sounds just a teeny bit familiar . . .
Here’s a related Guardian article about a 14 year old who had multiple positive lateral flow tests followed by a negative PCR test https://www.theguardian.com/world/2021/oct/09/negative-pcr-test-covid-symptoms-self-isolate?CMP=Share_AndroidApp_Other
Lateral flow is the way to go?
Most interesting. The way Freddie reports his results, this is almost more like a mini study than an anecdote. In theory PCR is much more accurate than LFT. But there are at least 2 reasons for the LTR +ve, PCR -ve discrepancy. (Reason 3 & 4 is just speculation on my part)
1) Timing – typically folk are doing the PCR swab a day or more after their LFT. Often folk seem to fight back Covid quite quickly, at least when their immune system is primed by the vaccine. I keep hearing of people where symptoms are only acute for 2 days. By the time some take the PCR, all viruses may have been killed.
2) Human error. Lab workers are always going to make mistakes, especially if over worked.
3) Faulty batches of reagent in some of the PCR labs?
4) In certain circumstances, the virus might decay on the swab before it makes it to the lab? (In some cases folk are posting their swab, not taking the test at a centre adjacent to a lab.)
Interesting ideas. Of these, I guess 1) might be the biggest discrepancy
Given that PCR can detect one molecule of RNA (when sufficient cycles are used which is generally the case) and given that PCR doesn’t require live virus or intact virus for a positive, I think that explanations (1) and (4) are unlikely to be correct. Human error, i.e. #2, is certainly possible as PCR is so sensitive it could pick up viral RNA from anywhere. #3 is unlikely in that a faulty batch of reagents would affect a whole series of contiguous PCR test and not just the odd one.
Mail-in of swabs is normal around here in Göteborg, Sweden. Several people I know have had results come back ‘inconclusive — no virus detected but the time delay is such that we cannot guarantee that the result is negative’. This was back when we were mailing all the swabs in to Stockholm, but I think they are all going to a place in Göteborg, now. At any rate, it has been many months since I have heard of that result.
My own lateral flow experience in mid July this year when I had Covid ties in exactly with yours Freddie. My pattern of positive and negative tests was identical and correlated exactly with the severity of symptoms. I agree with you 100% about their use in place of vaccine passports that like the efficacy of wearing masks before them are being bulldozered through despite mounting evidence of their ineffectiveness.
All hail the mountain of plastic!
it kind of restores my faith in my common sense and good practice. We all take our own responsibility for the action we take every day without imposing any view on others (my action might not be better or worse than others, are simply what I feel to do at this point in time based on my personal risk assessment. I say this in response to those comments being utterly shocked by the fact that Freddie had the vaccine, it is his business and none else! Also, he doesn’t t patronise any other into following his choice. What I find compelling though is the argument of using the LFTs as a way to avoid vaccine passports until the situation is really under control and we won’t need LFTs anymore. They have the same level of accuracy and can be compared to a very similar level of prevention as having a Covid Passport. We cannot deny the health issue and we need to fight the one-size-fits-all solution (like Covid Passport). LFTs are a suitable alternative (especially equal for all if kept free). It is rather unnerving to know that shadows are cast on this device which I think is keeping the social pressure under control. Just take a look at what it is happening in Italy where people are either forced to get vaccinated to work (not just for participating in social life) or pay an average of 45 EUR per week to get tested. I decided to be vaccinated, and I keep testing on a weekly basis as I know vaccines do not prevent the virus, but I would boycott anything that would force vaccine mandate in any form or shape as it doesn’t prove any safety at all and it is in breach with my ethics of freedom of choice.
I always accepted that COVID vaccines were developed in a big hurry, to stem a major social and economic catastrophe, and that they are not going to be anywhere near perfect, at least not for a year or two (or three). But we all agree that 70% or 80% protection is a lot better than 0%, but it is 70% and not 99%. I think people forgot what they were dealing with, wanted to return to normality asap, and slumped back into the extremely high standard of 21st Century living pre-COVID, with no threat to anything, and a life expectancy of hundreds of years.
I hope you have submitted this to the UK Gov’s current consultation/call for evidence (albeit anecdotal) on their proposed “Plan B” !
Mon Dieu! This article was disappointing, in that it did not include a detailed analysis of Call My Agent. That would have been worth discussing, especially with the erudite commentators on UnHerd.
I would like to add something. Pre-2020 I have had flu and bad colds and guess what the symptoms were :
Lack of taste and smell
It’s why we used to go to bed or lie on the sofa re-watching movies for a week. Back then we used to use tissues and throw them away now we just re-breathe the stuff back in from “the mask”.
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