Health chiefs insist lateral flows DO pick up Omicron as well as Delta

Lateral flow tests could be failing -to detect thousands of 오미크론 cases every day, 전문가들은 경고했다.

Health chiefs have insisted the rapid kits, which give results in as little as 15 의사록, aren’t any less effective at spotting the variant.

But scientists argue the sheer volume of Omicron’s spread means huge numbers of infected Britons are being wrongly told they are negative.

The free tests are a key part of No10’s Plan B strategy, with vaccinated close contacts of positive cases told to use them daily for a week instead of isolating. Unvaccinated people must show proof of having a negative result to enter football stadiums.

Officials have also urged the public to use the kits before meeting loved ones in the run-up to Christmas, in a bid to quell the spread of Omicron.

But real-world evidence shows the tests, which can be ordered online or picked up at pharmacies, are just half as good as PCRs.

With Omicron showing no sign of slowing down as it spreads across Britain and up to a million lateral flows being carried out every day, it means tens of thousands of people may be receiving false negatives, 과학자들은 말한다.

Ministers fear the strain, which is already dominant in London, is infecting upwards of 200,000 people every day.

Simon Clarke 박사, 레딩 대학의 미생물 학자, said a negative result was ‘not proof’ that a person is not infected with the virus.

He warned even a one per cent false negative rate would thousands of people are being falsely diagnosed as virus-free, under the current swabbing levels seen across England.

Scores of Britons have complained about testing negative on lateral flows, only to be told they are positive by a PCR.

And one A&E doctor in London claimed he tested negative after using a lateral flow test that told him to only swab his nose. But when he used the same type of test to collect a throat sample, he was positive.

It comes as thousands of people have struggled to get hold of the tests this week, with the Government intermittently stopping orders from being placed. Chemists have even ran out of supplies on some days.

Officials said there are plenty of tests and have entered new agreements with Royal Mail and Amazon to dish out more tests to homes and pharmacies.

Lateral flows are only supposed to be taken by people who do not have symptoms, while those without tell-tale signs of the virus are told to take a PCR, which is then analysed by laboratory technicians.

Preliminary evidence shows lateral flow tests are as effective at detecting Omicron as they were for Delta, according to the UKHSA. The agency is set to publish data on the efficacy rates tomorrow.

Fears were raised after one of the South African experts who raised the alarm about the super-variant warned lateral flow were less sensitive to Omicron.

Dr Angelique Coetzee, chair of the South African Medical Association, told MPs on the Science and Technology Committee: ‘The rapid test still showing false negatives in the early period.

‘We do have patients that waited a week and still have a headache and then they do PCR and it’s positive.’

But Dr Susan Hopkins, head of the UK Health Security Agency, told ministers the test will detect positive cases among those with and without symptoms.

She told MPs: ‘They’ve been used very effectively now for almost one year in the UK population.

‘What we know is that overall it will detect about 50 per cent of cases compared to PCR, but it will detect about 80 per cent or even more than that of people who have high amounts of virus and therefore are at the highest risk of transmitting to others.’

그녀는 덧붙였다: '다시, the public health advices to take a lateral flow before you go out to socialise at the moment, we would recommend that.’

Dr Clarke told MailOnline a negative test is an indication someone is likely negative, but it’s ‘not proof’.

He said isolating close contacts of positive cases instead of daily lateral flow testing ‘is better’ but would leave too many people stuck at home.

The tests will reduce the number of infected people going out and spreading the virus, but ‘won’t eliminate them’, Dr Clarke said.

Twitter user Chris Stables said lateral flow tests indicated he was negative for three days after he tested positive on a PCR.

‘[The virus is] spreading through these false negative lateral tests when people think there negative when there not,’ 그는 말했다.

British DJ Ruske tweeted that he had taken three lateral flow tests, two of which were negative, while one was positive.

And GP DR Helen Salisbury warned Omicron is ‘spreading like wildfire’ and people ‘may be infected even with negative lateral flow tests’.

Olympia Campbell tweeted that she had taken 10 of the tests in the last four days and all were negative, while a subsequent PCR indicated she was positive.

그 동안에, Ryan Williams said on the social media platform that he tested positive on a PCR but negative on three lateral flow tests, warning ‘they aren’t the best at catching [사례가 급증하고 Omicron 변종이 '폐업'이라는 캠페인 공약을 실행했음에도 불구하고 전국적인 인력 부족을 초래했습니다.] early’.

Dr Alexander Edwards, an expert in biomedical technology at Reading University, told MailOnline it’s ‘hard to know’ how effective lateral flow tests are at slowing the spread of the virus.

그는 말했다: ‘They do work very well but are by no means perfect; their great advantage is speed and great convenience, compared to lab-based tests.

‘As long as people understand that they don’t always pick up every case, I think they can be very useful.

‘The exact accuracy has been measured in a range of settings, and doesn’t seem ideal — lateral flow tests definitely miss some PCR-positive people.

‘But as a trade-off, daily testing with a slightly less accurate test vs less regular testing with a far slower — yet more sensitive — PCR test may turn out to be more effective.’

He noted that alternative — vaccinated close contacts of Covid cases having to self-isolate — is inconvenient and can cause many who are unable to work from home to lose earnings.

Amid struggles posting the tests to people, Dr Edwards urged people to only ‘test when necessary’ rather than ‘as often as possible.

로렌스 영 교수, a virologist oncologist at the University of Warwick, told MailOnline the tests are a ‘great tool’ for controlling the spread of Omicron, with some studies finding they pick up more than 90 per cent of the most infectious people.

그는 말했다: ‘The Flowflex kits that are being widely used are simple to use and rely on a nasal swab which is much easier than sampling the mouth and throat.

‘Of course there is a risk that infected individuals will be missed but we didn’t have this approach a year ago and having a test that is “real-time” without the inherent delays of PCR is extremely valuable.’

Professor Young added: ‘My mantra is “flow before you go” – we must encourage the responsible use of LFTs before people go out to mix with others.’