Covid England: Asymptomatic people won’t need confirmatory PCR from January 11, say health chiefs

Confirmatory PCR tests will no longer be needed for people testing positive for Covid on a lateral flow test, health chiefs confirmed today.

Previous guidance to back up positive rapid tests with more accurate lab results will be removed from January 11.

The UK Health Security Agency (UKHSA) announced the move amid sky-high case numbers across England. 

The move will free up capacity in laboratories for PCR tests for those who have Covid symptoms.

People who receive a positive result on a lateral flow device (LFD) will be required to self-isolate immediately, without requiring PCR confirmation. 

UKHSA said this is a temporary measure while Covid rates remain high across the UK.

Officials said that while levels of Covid are high, the ‘vast majority’ of people with positive LFD results can be confident they have the virus.

They estimated the number of ‘false positives’ results, where people without the virus get a positive LFD result, are as low as three in 10,000.

However with just under 1.5million of LFD tests being conducted across the UK every day this could lead to thousands of people who don’t have Covid having to isolate. 

People who have Covid symptoms, such as a high temperature, a new, continuous cough, or change in sense of taste and/or smell should still get a PCR test, UKHSA said. 

UKHSA chief executive Dr Jenny Harries said: ‘While cases of Covid continue to rise, this tried-and-tested approach means that LFDs can be used confidently to indicate Covid-19 infection without the need for PCR confirmation.

‘It remains really important that anyone who experiences Covid symptoms self-isolates immediately. They should also order a PCR test on gov.uk, or by phoning 119.

‘I’m really grateful to the public and all of our critical workers who continue to test regularly and self-isolate when necessary, along with other practical and important public health behaviours, as this is the most effective way of stopping the spread of the virus and keeping our friends, families and communities safe.’

UKHSA have said lateral flow devices are 80 per cent effective at finding people with high viral loads of Covid. 

Health chiefs said the change would be kept in place until Covid prevalence dips below one per cent.

Prevalence last week was around four per cent according to the Office for National Statistics (ONS) infection survey. 

Experts hailed the move as sensible given current case numbers, arguing PCR confirmations ‘waste time’ during infection surges.

SAGE member John Edmunds, a modeller at the London School of Hygiene & Tropical Medicine, said: ‘This change makes a lot of sense. 

‘When the prevalence is high — and it is incredibly high at the moment — almost everyone who tests positive with a lateral flow test will be a true positive. 

‘There is really no need to confirm this with a PCR, a step that not only wastes time but costs a lot of money and uses up laboratory resources that could be better used elsewhere. There are down sides to this change. 

‘We would have slightly less information on the relative prevalence of the different variants circulating in the community, as PCR swabs undergo genotyping and sequencing, and the daily number of confirmed cases may need more careful interpretation. 

‘Overall, though, I think that these downsides are worth it.’

Sir David Spiegelhalter, chair of the Winton Centre for Risk and Evidence Communication at the University of Cambridge, said: ‘This seems a sensible move. 

‘We argued back in October that it seemed fairly pointless to do a confirmatory PCR after a positive lateral flow test.

‘This is even more true now: with current infection rates, a positive LFD followed by a negative PCR would still mean it was very likely that you were carrying the virus. 

‘PCRs are useful for surveillance, sequencing and have legal status, but if we want to focus on isolating people who are infectious, then LFDs may be adequate. But they need to be reported.’

Dr Hayley Jones senior lecturer in medical statistics at the  University of Bristol said assuming a positive LFD test meant you had Covid was ‘sensible’ but urged people not to believe that the opposite meant they were virus-free. 

‘At current high levels of infection in the population, it’s sensible to assume you’re infectious if you have a positive lateral flow test result, without a “confirmatory” PCR,’ she said.

‘But it’s crucial to remember that the reverse is not true: a negative lateral flow result doesn’t guarantee that you don’t have Covid or that you’re not infectious, so it remains important to get a PCR test if you have symptoms regardless of a negative lateral flow result.’

 However some have slammed the decision, arguing the drop in PCR tests, which being processed in a lab can reveal more information about the Covid virus, could lead to a new variant emerging in the UK undetected.

Liberal Democrat, Layla Moran MP chair of the all-party parliamentary group on Coronavirus, said: ‘The Alpha variant was originally found in Kent and with hundreds of thousands of new infections in the UK daily, there is a greater chance of another variant emerging here.

‘Effective sequencing and testing enabled South Africa to warn the world about Omicron and the risk of this change is that we could miss new variants that may be more deadly, infectious or resistant to vaccines.’

Professor Sheila Bird, formerly programme leader of the MRC Biostatistics Unit at the University of Cambridge said the UKHSA figure of tests being 80 per cent effective at catching high viral flow individuals was based on data from the Alpha and Delta waves. 

‘For transparency, results for these Omicron-era dual-testing evaluations should be placed in the public domain at the earliest opportunity,’ she said.

This is the second time in the pandemic that the UK has suspended confirmatory PCR testing previously doing so in January 2021 during a similar surge in Covid case numbers.