Scientist Explains How Your Lateral Flow Test Changes According To How Infectious You Are

Lateral flow tests are accurate in tracking how infectious someone is, according to an epidemiologist.

Prime minister Boris Johnson has announced from the January 11 the rules around PCR tests and Lateral Flow tests (LFTs) will be changing.

Asymptomatic people who test positive on LFTs no longer need to take follow-up PCR tests. Instead, they have to start their self-isolation period immediately, rather than waiting for another test result.

Symptomatic people are advised to continue taking PCRs.

LFTs are an increasingly important part of the UK’s response to Covid even though they have been criticised in the past for not consistently detecting the virus.

US epidemiologist and immunologist Dr Michael Mina explained how they work on Twitter amid concerns LFTs were not going to pick up the new highly-transmissible variant, Omicron.

Responding to questions about why some people stay negative on LFTs the first few days they have symptoms, he explained: “This is expected. Symptoms don’t [equal] contagious virus.

“This is literally a reflection of the fact that vaccines are doing their job!”

He tweeted again: “Rapid tests work with Omicron.

“Omicron is mutated mostly in spike [protein].

“Rapid tests don’t detect the spike.”

Dr Mina added that newly symptomatic people who are coming up negative on LFTs are “probably not infectious” but it’s advisable to test again the next day.

“I am primarily trying here to explain that it is expected for people to show symptoms earlier than before, as a result of vaccination and developed of acquired immunity.

“My point was that symptoms SHOULD be expected to arise early now that people’s immune systems don’t have to spend 5+ days realising someone is infected with a new virus. Now our immunity kicks in fast, and with it, symptoms do too.”

He also shared a series of photos of LFTs each day during someone’s isolation period.

These images clearly show the positive line on each test strengthening during the first part of the self-isolation before fading out again by day 10.

This demonstrates that the individual who was taking the tests was at their most infectious during the middle of their isolation.

Another graph from the BBC was also circulating online, emphasising how LFTs pick up high levels of infection compared to PCRs.

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Pharmacists Claim They Were Raising Concerns About The Supply Of Lateral Flow Tests ‘Weeks Ago’

Pharmacists warned the government about supply of lateral flow tests “weeks ago”, according to the CEO of the Association of Independent Pharmacies.

Leyla Hannbeck told HuffPost UK that pharmacies were now at the forefront of this particular crisis, as the store of self-test kits has run dry shortly before the biggest social night of the year – New Year’s Eve.

She explained: “When pharmacists order, it doesn’t arrive or just one box arrives.

Some days, they go completely without. It’s just not sufficient, it’s very sporadic.”

Hannbeck said, despite the government’s claims that distribution and supply chain was still functioning, “none of it is working well”.

Nearly three quarters of pharmacies in London ran out of LFTs on Wednesday, according to the Evening Standard.

“They should have put proper plans in,” Hannbeck continued.

“A lot of stress put on our routine to manage this. We’ve been put at the forefront of this without any support.

“We raised it, we raised a few weeks ago – we were seeing people come in through the doors and we were seeing issues with supply and that it wasn’t enough.

“The government needs to manage supply and demand. It cannot continue for weeks to come.”

The gov.uk website shows that it’s not possible to order LFTs online either.

The gov.uk website is still advising people to pick up rapid lateral flow tests from a pharmacy
The gov.uk website is still advising people to pick up rapid lateral flow tests from a pharmacy

test-for-coronavirus.service.gov.uk/

She predicted it was not going to get any easier in the weeks to come either, due to both the Christmas period and the change in government guidelines.

Daily testing is now in place for anyone who has been in close contact with someone who tested positive for Covid, while the self-isolation period for positive cases has been shorted to seven days as long as the individual tests negative – on lateral flow tests – twice in a row.

Everyone has been encouraged to test themselves before socialising, too.

“People want to be responsible and follow the government guidelines – but there are no tests available,” Hannbeck pointed out.

She said it was “logical” that the demand would go up because of the government’s guidelines, but nothing was happening “in terms of managing supply”.

“You can imagine a kit with seven tests in it for a family of five – it will go immediately.

“We can’t continue with it – something’s got to be done.”

Hannbeck also claimed that the shortages are only going to continue as the general population continues to use LFTs for before they go to work, for normal livelihoods, returning from holidays, going back to school.

Hannbeck did tweet the UK’s Health Security Agency shortly before Christmas, claiming: “Your poor handling of the supply of lateral flow tests to pharmacies and the bureaucratic process around it has created a lot of stress for pharmacy teams and for patients during the busy Christmas period. You need to urgently resolve this.”

She also raised the same issue on December 16, tweeting: “Why on earth are pharmacies only allowed restricted supply of lateral flow tests (one box per day) when there is huge public demand?

“How are we supposed to manage when we don’t get the supply to ensure public can access? The government needs to sort this out ASAP.”

Health secretary Sajid Javid has admitted that the supply of lateral flow test kits will be “constrained” in the next two weeks.

In a letter sent to MPs on Wednesday, he said: “In light of the huge demand for LFTs seen over the last three weeks, we expect to need to constrain the system of certain points over the next two weeks to manage supply over the course of each day, with new tranches of supply released regularly throughout the day.”

He suggested MPs should encourage constituents towards their local pharmacists and then see if “their local authority is distributing tests” or find them at local community facilities.

Labour has accused the government of a “shambles”, with shadow health secretary Wes Streeting calling for all NHS workers to get priority access to tests.

It is important to note that the government has promised to deliver eight million tests before New Year’s Eve.

A spokesman from UKHSA said: ”The UK’s testing programme is the biggest in Europe with almost 400 million tests carried out since the start of the pandemic.

“We are delivering record numbers of lateral flow tests to pharmacies across the country, with almost eight million test kits being made available to pharmacies between today and New Year’s Eve.

“We have made 100,000 more PCR booking slots available per day since mid-December and we are continuing to rapidly expand capacity – with over half a million tests carried out on December 23 alone and delivery capacity doubled to 900,000 PCR and LFD test kits a day.

“If you have not been able to get the test you need from gov.uk, please keep checking every few hours as more PCR and LFD tests become available every day.”

There has also been a worldwide shortage of LFTs and PCR tests in recent weeks.

The department for health and social care has been approached for comment.

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Chinese-Made Covid Tests Exempted From New UK Mandatory Health Standards

PAUL ELLIS via Getty Images

Ministers have tightened up the law to raise standards for Covid tests sold privately in England – but have exempted Chinese-made tests which have cost the taxpayer billions, HuffPost UK can reveal.

New regulations from the department of health and social care (DHSC) aim to stamp out “poor quality tests” that could give the public a false sense of security and allow people to spread the virus unwittingly.

But the higher performance standards, quietly introduced this week, include a loophole that explicitly excludes lateral flow tests previously bought by the government such as those bought from Innova Medical Group at a cost of more than £3bn.

British manufacturers privately welcome the new regime as they believe their home-grown tests are cheaper and more reliable than the Innova tests.

But many in the UK bio industry question why ministers are exempting the Chinese-made devices from the same high standards.

The rules, which will kick in from September 1, have also prompted fresh suspicions that the government is moving away from giving the public and businesses free rapid tests and will instead expect them to pay for the devices commercially.

The new secondary legislation – The Medical Devices (Coronavirus Test Device Approvals) (Amendment) Regulations 2021 – gives Sajid Javid unprecedented power over which Covid tests can be sold on the open market in England.

Firms will have to pay the government £14,000 for any application and any tests not deemed up to the grade will be removed from sale by law.

Retailers, distributors and manufacturers of tests that attempt to sell unvalidated tests would face sanction.

Currently, PCR or lateral flow tests can go on commercial sale in England as long as they carry a CE mark, which means they meet EU and UK requirements, but each manufacturer designs their own data collection and analysis methods to validate them.

Under the new proposals, the government will require that “all COVID-19 tests placed on the UK market undergo a mandatory validation process”, with the same standards applied equally to allow consumers to make a fair comparison.

A new DHSC document states: “It would undermine current public health goals if people used poor quality tests that give them a false sense of security.

“In the case of a false negative, this could see an infected individual unknowingly spread the virus. Conversely false positives could require business to close and people to isolate unnecessarily.”

But an explanatory memorandum to the new legislation states that “tests supplied by government will be exempt” from the new validation process.

The memo adds that contracts agreed by the government to supply NHS hospitals “can continue to be honoured by the manufacturer even if the test has failed validation”.

This has prompted anger among UK bioscience insiders, who believe that the Innova tests would compare badly with British-made rivals and who complain that ministers have done everything to favour the Chinese-manufactured products since last year.

Innova, which is based in California and funded by a private capital group by a Chinese-born businessman, uses tests produced by Chinese Biotime Biotechnology, in Xiamen city, Fujian province.

Publicly available contracts on the government’s website shows that £3.3bn has been spent to date on the company, as part of the £37bn allocated to the controversial Test and Trace service.

Innova’s 30-minute tests have been used for regular weekly testing of NHS and care home staff and in schools. Since April, any member of the public has also been able to order twice-a-week tests for free.

Yet concerns about cost and reliability have been raised repeatedly by critics, underscored when the US Food and Drug Administration (FDA) issued an alert about the test in June.

The FDA told Americans to “destroy the tests by placing them in the trash”, saying it had “significant concerns that the performance of the test has not been adequately established, presenting a risk to health”.

The UK’s Medicines and Healthcare products Regulatory Agency (MHRA) – which critics claim is an arm of the DHSC and not fully independent – then did its own risk assessment and found no similar action was needed here.

Aaron Chown – PA Images via Getty Images

Innova Covid-19 testing kit

Critics further point out that Innova’s own manufacturer’s instructions make clear the tests were designed for use only in symptomatic Covid cases, but the UK government allowed them to be used in asymptomatic cases as part of its “Operation Moonshot” plan to mass test the population.

Authorisation for the Innova test to be used by asymptomatic people at home was due to expire on June 22 but has been extended until August 28, but the new regulations have sparked hope that they can gradually be replaced by British alternatives.

But controversy dogs the Innova tests and the way the UK government has effectively taken ownership of its products. Innova branding has been dropped from the boxes used to deliver tests, replacing it with NHS branding.
Eyebrows were further raised when the DHSC decided to tweak the way in which the Innova test could be used.

Although the manufacturer’s “instructions for use” insist on the invasive and uncomfortable practice of taking a swab from the back of the throat, the government has quietly changed the rules to allow it to take swabs from the nose only.

Similarly, the original instructions for use made clear the tests were never intended for home use and were designed to be administered by a clinical professional.

The exemption for Innova from the new validation rules is seen by some British manufacturers as a way of avoiding the potential huge embarrassment of seeing their tests fail to match the standards of others, not least given large sums spent on them to date.

The legislation mandates a “desktop review” be undertaken of all Covid tests placed on the UK market and defines a set of minimum standards that these tests should meet.

One industry insider said the guidance document states that tests should achieve a minimum sensitivity rating of 95%, whereas the Innova test sensitivity rating achieved at Public Health England’s Porton Down lab was 57.5%.

One industry source said: “This means that the tests already selected won’t need to go through this exercise. It’s a disgrace. One rule for them…”

Another bioscience source said: “The UK industry was not totally confident with the way tests were evaluated for the NHS in the first place.”

Yet another said: “​​By appointing themselves ‘judge and jury’ of the Innova test, the DHSC has allowed itself to make fundamental changes to the Innova test’s characteristics, implementing them without any follow up Porton Down assessment.

“[These are] changes that would inevitably have had a significant detrimental impact on the test’s already underwhelming performance. Notably, to date, the government have not seen fit to publicly assess the impact of these wholesale changes.”

Shadow health minister Justin Madders told HuffPost UK: ”​​Given the concerns in the USA over the Innova tests and the fact they are only on a temporary approval here it does seem extraordinary that this legislation could allow Sajid Javid to let them carry on being used without being subject to the same approval processes as everyone else. Far more transparency is needed.

“This also seems to suggest that the government intends to move away from having Covid tests being provided free of charge. This has massive implications for public health and could seriously undermine efforts to reduce transmission of the virus. The government needs to come clean on whether they intend to introduce a charging regime for Covid test.”

The DHSC and the department for education raised suspicions that the distribution of free lateral flow tests could cease at the end of September, when a “review” will take place of their twice-weekly use in schools and to the wider public.

WPA Pool via Getty Images

Former health secretary Matt Hancock and Boris Johnson pushed ‘moonshot’ mass testing

Allyson Pollock, professor in public health at the University of Newcastle, said the bigger issue was that there was little evidence that testing of asymptomatic people – at home or in the workplace – was effective at all.

“This is about creating a market in tests which have questionable performance but above all, it’s still unknown despite the billions spent whether tests as part of a screening intervention actually help to prevent transmission,” she said.

“This isn’t a public health strategy, this is a commercial strategy. They want the public to get hooked on tests and employers to believe that testing is the way out. This is increasingly ridiculous given that the prevalence is low and falling now that immunity is being established.

“Secondary attack rates are low in the immunised population and infection likely to be mild and risks of transmission commensurately lower. Mass testing with lateral flow tests is an enormous waste of resources and it’s the antithesis of good public health.”

One key criticism of lateral flow tests is that their negative readings are being used as a “green light” to allow people to go about their daily lives, when in fact they were only ever designed as a “red light” test – when a positive reading tells people when they may have Covid and to get a gold-standard PCR test to check.

HuffPost UK has seen a letter from health minister Lord Bethell, sent last December to Tory backbencher Bill Wiggin, in which he makes clear the real risks to public health from asymptomatic mass screening.

In the letter, Bethell said: “We are not currently planning mass asymptomatic testing; swab testing people with no symptoms is not an accurate way of screening the general population, as there is a real risk of giving false reassurance.

“Widespread asymptomatic testing could undermine the value of testing, as there is a risk of giving misleading results. Rather, only people with COVID-19 symptoms should get tested.”

HuffPost UK

Lord Bethell letter on asymptomatic testing risks

Alba MP Neale Hanvey, who has raised the issue of Innova’s big government contracts and the failure to use rival tests made by Scottish-based firms such as Omega Diagnostics, said the letter was telling.

“This letter supports everything that I have said to [former health secretary] Matt Hancock and to other members of the department of health, that this is a grand folly. It’s giving people false reassurance and a huge cost to the public purse for no perceivable benefit.”

Hanvey added that the new mandatory guidance for commercial tests was “a fig-leaf for the government’s misdeeds”.

“What the government needs to do now is to cease supporting tests that we know are not designed for their current use, not picking up enough infectious cases and move swiftly to open the doors for the domestic market, to get access not just to private purchase, but to NHS supplied tests. Where is the global Britain and all of this mess?”

Boris Johnson has repeatedly declared that he wants home-grown rapid tests to be developed, but the UK bioscience industry has been increasingly frustrated that their tests were not approved by Porton Down labs despite other independent validation.

The UK government raised hopes earlier this year when it loaned manufacturing equipment to British companies and earmarked £1.15bn for a programme that would see rapid production. But virtually none of the money has been spent because British tests have not been approved.

One firm, Mologic, was so frustrated with the lack of validation of its tests that it threatened to sue the government. It has since been bought by the Bill & Melinda Gates Foundation and turned into a not-for-profit to help develop rapid tests to combat tropical diseases such as dengue, bilharzia, and river blindness, as well as Covid.

One UK bio industry source said: “They completely screwed the UK diagnostic industry. They invested in LFD [lateral flow device] machinery and are refusing to allow the factories to use them. Our firms are having to export world leading tests, two are in the top ten globally, while we import inferior ones.”

One bio industry source said: “I’m really unhappy that the government was signaling particularly to the UK manufacturers that we will provide you with a lot of support, and we’d like you to help us be self-sufficient in lateral flow tests by spring 2020.

“The companies all took them at their word. Then the government basically says well we didn’t actually promise we’d buy anything from you. That is a little two faced.”

A diagnostics expert said that the new commercial validation process was at least a signal that there would be a shift to getting the public to buy their own tests and that the cheaper price and better performance of British tests would mean that from the autumn “everyone will get a market share”.

“The lateral flow tests being provided to the population free of charge at the moment, at some point, people will either have to start buying themselves or employers will have to start buying them for their employees and there will be only be a certain amount that are provided free of charge.”

Dan Kitwood via Getty Images

Health secretary Sajid Javid now has sweeping powers over commercial tests

Industry insiders believe that firms like Mologic and Omega will submit their tests under the new system and expect to get approval. “This is all in readiness for when DHSC stop giving away free tests for a lot of use cases and reopens the private market,” one said.

Some insiders believe that the Innova test was adopted by the government early in the pandemic simply because it could be provided in mass numbers and that even though its performance is “not perfect” it was “good enough for what it does”.

Defenders of the Innova test believe it can be effective at detecting high viral loads quickly, claiming there is evidence to back this up.

The DHSC has in recent months pivoted to using another Chinese-made test produced by OrientGene, which some in Whitehall believe produces more reliable results than Innova.

Doris-Ann Williams, chief executive of the British In-Vitro Diagnostics Association (BIVDA) said one problem with the new mandatory system was that it would add needless regulation when existing systems could have been updated.

“While we appreciate the government is acting with the best of intentions by introducing this legislation, we still feel a better solution would have been to amend the existing regulation so that the MHRA, who are a world leading regulator for medicines and medical devices, could have ensured the right products are available to the British population.

“However, industry is committed to working under the legislation and alongside UKAS [UK Accreditation Service] to ensure COVID antigen tests are reliable and safe.”

The government insists that its own tests should be exempt from the new mandatory testing standards in an effort to avoid duplication of previous validations.

“This is because the market validation is based on the validation DHSC has
been doing for public procurement of tests as such these two validation process are judged to be equal,” according to the explanatory memorandum accompanying the new regulations.

“As such DHSC will place tests onto to the market without undergoing the regulatory validation process conducted by DHSC to control access to
the UK market.”

A spokesperson for the DHSC said: “Private testing continues to play an important role in managing COVID-19 by supplementing and supporting NHS Test & Trace as we learn to live with this virus.

““As we ease restrictions, including for travel, the role of private testing is increasing and our regulations are ensuring consumers can be confident tests they buy give accurate results and are of sufficient quality.”

They added that private testing will continue to play a role as part of the overarching strategy for managing COVID-19.

The department believes that it is important to introduce a regulatory regime to ensure those tests available on the market are validated for performance, regardless of whether the government is also providing free tests.

A spokesperson for Innova Medical Group said: “Our tests have proven by independent studies to be very effective in detecting individuals who are considered infectious regardless of symptoms.”

They said that the latest UK test had shown it “detects nearly 100% of infected asymptomatic individuals who are considered infectious to others, and there was very little difference in the specificity between self-testing (99.1%) and testing performed or observed by a professional (99.8%)”.

“We understand FDA’s health risk concern for the US market as they have not evaluated or authorised the Innova test in the US.

“In simple terms, the regulator won’t confirm a product is safe to use until it has evaluated and authorized a product itself. None of the FDA inspectional observations concern the performance of the test.”

The company said that its test had been widely used, studied, tested, scrutinised and analysed. Its point of care test had been approved in Germany, France, Netherlands, Finland, Sweden, UK, Austria, Estonia, Finland, Israel, Malaysia, and Sultanate of Oman. Its self-test kit had been approved in Austria and the UK.

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