Countries should use pooled testing at start of future pandemics because it works just as well, experts say
- Olivet Nazarene University in Illinois used pooled testing to control Covid cases
- Method involves multiple swabs being tested for the virus together
- If the virus is not detected they are all assumed to be negative for the virus
- But if the group is positive then each sample is tested again individually
Virus tests should be analysed in batches at the start of future outbreaks because doing so can contain diseases quicker, experts say.
When the coronavirus pandemic began last year, technicians laboriously checked swabs individually.
But now scientists at Olivet Nazarene University (ONU) in Illinois have found pooled saliva testing is just as effective.
The method involves combining multiple samples together and analysing them for traces of a virus.
If it is not detected in the sample, then all participants are presumed to be negative.
But should it be picked up, then all the people involved in the sample need to be re-tested again individually.
The UK was late to launch pooled testing to speed up its Covid diagnosis, lagging behind other countries including the US and Germany.
Virus tests should be analysed in batches at the start of future outbreaks because it can contain emerging diseases like Covid quicker, experts say (stock). Pictured: A woman is tested for Covid at a testing centre
A pilot scheme was only launched in November — near the end of England’s second lockdown — before being rolled out more widely.
In the study — published in the journal Microbiology Spectrum — the university’s 3,500-odd students had saliva samples taken at least once a week throughout the spring term.
Saliva swabs were analysed in groups of five or ten, with batches that tested positive seeing each sample individually checked for the virus.
Positive cases were then asked to isolate, and their close contacts were traced by the university.
It detected 83 per cent of the Covid cases — similar to accuracy levels seen for the gold-standard nasal swabs.
The academics said it cost the university just $0.43 (32p) to process each sample, which they claimed was one of the lowest prices ever for testing.
The institution decided to bring in the measure after facing a disrupted autumn term where outbreaks led to classes being cancelled or postponed.
Other measures in use at the time of the study included wearing face masks indoors, social distancing of two metres and limiting class sizes to 50 students.
Attendees were also asked to self-isolate for 14 days before returning to the campus.
Timeline of UK’s pooled testing regime
August 2020: Former Prime Minister Tony Blair and former Health Secretary Jeremy Hunt call on the Government to start using pooled testing. The strategy is already being deployed in other countries at this point.
September 2020: There are suggestions that up to 50 swabs could be tested at once under Boris Johnson’s plan to process 10million swabs a day.
October 2020: China, the US, Germany and Israel are all using pooled testing. In the UK it has been taken up by some NHS Trusts such as one in Devon.
November 2020: Towards the end of the month the UK launches a pilot pooled testing scheme for students. It came amid revelations on ‘Operation Moonshot’ and plans to carry out 10million Covid tests a day.
ONU describes itself as a small Christian university in the midwestern United States.
Study lead author associate professor Daniel Sharda said: ‘Our study demonstrates a significant step forward for achieving rapid test results on a large scale, while preserving supplies and reducing costs.
‘Future pandemic should use pooled strategies from the very beginning, when tests are otherwise limited.’
Some NHS trusts including North Devon Healthcare NHS Trust started using pooled testing near the beginning of the pandemic.
The Government faced significant pressure from scientists and politicians including former Prime Minister Tony Blair to deploy the method wider in the UK.
But the first pilot was only launched on November 24, which explicitly aimed to use the method for student households.
Concerns were sparked last September up to 50 swabs could be tested together at once as Boris Johnson tried to dish out millions of tests a day.
Researchers say five to ten swabs should be pooled for each test, and only among asymptomatic individuals.
The UK struggled to get its testing regime off the ground at the start of the pandemic, leaving ministers grappling in the dark to understand how far the virus at spread in the country.
At one point the country almost ran out of a key ingredient for PCR tests, meaning fewer tests could be carried out.
But in April last year former Health Secretary Matt Hancock set a target of 100,000 tests a day by the end of the month.
Boris Johnson has poured more than £1billion into testing launching sites across the country and providing lateral flow tests for every household.
Britain is currently carrying out almost a million PCR and lateral flow tests for Covid every day.
The UK Health Security Agency — which took over from Public Health England — has been contacted for comment.