The number of people infected with Covid-19 who were missed by lateral flow testing is substantially higher than thought, University of Birmingham researchers say in a report published in the BMJ.
The authors acknowledge that LFTs are an important tool in controlling the coronavirus pandemic, but say claims that the devices can identify the vast majority of cases have been overstated and can give false reassurance.
LFTs have been recommended for widespread use, largely based on predictions made by mathematical models.
While empirical data shows LFTs give a positive result when the virus is present on a swab in high quantities, and therefore can detect people who are likely to be infectious, the proportion missed who are infectious has not been evaluated.
To address this gap, the researchers drew on empirical data from several sources to predict the proportion of LFTs that produce negative results in those with a high risk of Sars-CoV-2 infectiousness.
They then compared these with predictions made by influential mathematical models.
Their focus was to identify the probability that people are likely to be infectious and that they test negative on Innova.
Their results are based on testing in three settings: symptomatic testing at an NHS Test-and-Trace centre; mass testing in Liverpool in residents without symptoms; and in students at the University of Birmingham.
The analysis predicted that of those with a viral culture positive result, Innova would miss 20 per cent attending an NHS Test-and-Trace centre, 29 per cent without symptoms attending municipal mass testing, and 81 per cent attending university screen testing without symptoms, along with 38 per cent, 47 per cent, and 90 per cent of sources of secondary cases.
By comparison, two mathematical models significantly underestimated the numbers of missed infectious people.
One model suggested 8 per cent, 10 per cent, and 32 per cent of cases would be missed in the three settings, while the other assumed no cases would be missed.
Consequences of false negatives is significant
The authors stress that evaluating the accuracy of a test for current infection or infectiousness is challenging owing to the lack of a reference standard, and say there is the potential for error in their estimates.
“The findings in this analysis therefore must be taken as illustrative and not exact,” they say.
But they say that this data is “currently the best available and clearly show that missing people with current infection or who are infectious is possible in all settings".
“Allowing for the uncertainties in the results from our analyses, the proportion of people with current infection missed by the Innova LFT is likely to be of public health importance, particularly in settings with greater proportions of infectious people with lower viral loads, where the tests are often being applied,” said lead author Jon Deeks, professor of biostatics at the University of Birmingham.
“Policymakers need to ensure that the public are aware of the risk of being infectious despite testing negative, and that tests are not used in situations where the consequences of false negative results are considerable."
The UK has spent more than £7bn on lateral flow devices since mid-2020 on the proviso they could reduce Covid transmission by up to 90 per cent. Yet there is lack of hard evidence on this promised impact.
The World Health Organisation has cautioned against mass asymptomatic testing because of this evidence shortfall, as well as the high costs and risk of diverting resources from more important activities.
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What is tokenisation?
Tokenisation refers to the issuance of a blockchain token, which represents a virtually tradable real, tangible asset. A tokenised asset is easily transferable, offers good liquidity, returns and is easily traded on the secondary markets.
Key figures in the life of the fort
Sheikh Dhiyab bin Isa (ruled 1761-1793) Built Qasr Al Hosn as a watchtower to guard over the only freshwater well on Abu Dhabi island.
Sheikh Shakhbut bin Dhiyab (ruled 1793-1816) Expanded the tower into a small fort and transferred his ruling place of residence from Liwa Oasis to the fort on the island.
Sheikh Tahnoon bin Shakhbut (ruled 1818-1833) Expanded Qasr Al Hosn further as Abu Dhabi grew from a small village of palm huts to a town of more than 5,000 inhabitants.
Sheikh Khalifa bin Shakhbut (ruled 1833-1845) Repaired and fortified the fort.
Sheikh Saeed bin Tahnoon (ruled 1845-1855) Turned Qasr Al Hosn into a strong two-storied structure.
Sheikh Zayed bin Khalifa (ruled 1855-1909) Expanded Qasr Al Hosn further to reflect the emirate's increasing prominence.
Sheikh Shakhbut bin Sultan (ruled 1928-1966) Renovated and enlarged Qasr Al Hosn, adding a decorative arch and two new villas.
Sheikh Zayed bin Sultan (ruled 1966-2004) Moved the royal residence to Al Manhal palace and kept his diwan at Qasr Al Hosn.
Sources: Jayanti Maitra, www.adach.ae
Countries recognising Palestine
France, UK, Canada, Australia, Portugal, Belgium, Malta, Luxembourg, San Marino and Andorra
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Living in...
This article is part of a guide on where to live in the UAE. Our reporters will profile some of the country’s most desirable districts, provide an estimate of rental prices and introduce you to some of the residents who call each area home.
How to apply for a drone permit
- Individuals must register on UAE Drone app or website using their UAE Pass
- Add all their personal details, including name, nationality, passport number, Emiratis ID, email and phone number
- Upload the training certificate from a centre accredited by the GCAA
- Submit their request
What are the regulations?
- Fly it within visual line of sight
- Never over populated areas
- Ensure maximum flying height of 400 feet (122 metres) above ground level is not crossed
- Users must avoid flying over restricted areas listed on the UAE Drone app
- Only fly the drone during the day, and never at night
- Should have a live feed of the drone flight
- Drones must weigh 5 kg or less
Red flags
- Promises of high, fixed or 'guaranteed' returns.
- Unregulated structured products or complex investments often used to bypass traditional safeguards.
- Lack of clear information, vague language, no access to audited financials.
- Overseas companies targeting investors in other jurisdictions - this can make legal recovery difficult.
- Hard-selling tactics - creating urgency, offering 'exclusive' deals.
Courtesy: Carol Glynn, founder of Conscious Finance Coaching
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Position: legal consultant with Al Rowaad Advocates and Legal Consultants.
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Indoor cricket in a nutshell
Indoor Cricket World Cup – Sep 16-20, Insportz, Dubai
16 Indoor cricket matches are 16 overs per side
8 There are eight players per team
9 There have been nine Indoor Cricket World Cups for men. Australia have won every one.
5 Five runs are deducted from the score when a wickets falls
4 Batsmen bat in pairs, facing four overs per partnership
Scoring In indoor cricket, runs are scored by way of both physical and bonus runs. Physical runs are scored by both batsmen completing a run from one crease to the other. Bonus runs are scored when the ball hits a net in different zones, but only when at least one physical run is score.
Zones
A Front net, behind the striker and wicketkeeper: 0 runs
B Side nets, between the striker and halfway down the pitch: 1 run
C Side nets between halfway and the bowlers end: 2 runs
D Back net: 4 runs on the bounce, 6 runs on the full
Going grey? A stylist's advice
If you’re going to go grey, a great style, well-cared for hair (in a sleek, classy style, like a bob), and a young spirit and attitude go a long way, says Maria Dowling, founder of the Maria Dowling Salon in Dubai.
It’s easier to go grey from a lighter colour, so you may want to do that first. And this is the time to try a shorter style, she advises. Then a stylist can introduce highlights, start lightening up the roots, and let it fade out. Once it’s entirely grey, a purple shampoo will prevent yellowing.
“Get professional help – there’s no other way to go around it,” she says. “And don’t just let it grow out because that looks really bad. Put effort into it: properly condition, straighten, get regular trims, make sure it’s glossy.”
Killing of Qassem Suleimani
