Countries should use pooled testing at the 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 testing multiple swabs together for the virus
- If the virus is not detected, they are all assumed to be negative for the virus
- But if the group is positive, each sample is retested individually
Virus testing should be batch analyzed at the start of future outbreaks, as this can catch diseases more quickly, experts say.
When the coronavirus pandemic began last year, technicians laboriously checked the swabs individually.
But now scientists at Olivet Nazarene University (ONU) in Illinois have found that pooled saliva testing is just as effective.
The method involves combining multiple samples with each other and analyzing them for traces of a virus.
If it is not detected in the sample, all participants are assumed to be negative.
But if it is picked up, all people involved in the sample will have to be retested individually.
The UK was late in launching pooled tests to speed up Covid diagnosis, lagging behind other countries including the US and Germany.
Virus testing should be analyzed in batches at the start of future outbreaks because it can catch emerging diseases like Covid more quickly, experts (stock) say. Pictured: A woman is tested for Covid at a testing center
A pilot project was not launched until November – towards 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 during the spring.
Saliva swabs were analyzed in groups of five or ten, with batches testing positive, each sample being checked for the virus individually.
Positive cases were then asked to isolate and their close contacts were traced by the university.
It detected 83 percent of Covid cases — similar to the levels of accuracy seen for the gold standard nasal swabs.
The academics said it cost the university just $0.43 (32 pence) to process each sample, which they believe was one of the lowest prices ever for testing.
The institution decided to introduce the measure after a disrupted fall period when outbreaks resulted in classes being canceled or postponed.
Other measures used at the time of the study included wearing face masks indoors, social distancing two meters and limiting class size to 50 students.
Attendees were also asked to self-isolate for 14 days before returning to campus.
Timeline of the UK’s pooled testing regime
August 2020: Former Prime Minister Tony Blair and former Health Secretary Jeremy Hunt are calling on the government to start using pooled tests. The strategy is already being deployed in other countries.
September 2020: There are suggestions that up to 50 swabs could be tested at once under Boris Johnson’s plan to process 10 million swabs per day.
October 2020: China, US, Germany and Israel all use pooled tests. In the UK it has been taken over by some NHS Trusts, such as one in Devon.
Nov 2020: Towards the end of the month, the UK will launch a pilot pooled testing program for students. It came amid revelations about ‘Operation Moonshot’ and plans to conduct 10 million Covid tests per day.
ONU describes itself as a small Christian university in the Midwestern United States.
Lead author of the study, associate professor Daniel Sharda, said: ‘Our study shows a significant step forward in achieving rapid test results at scale, while preserving inventories and reducing costs.
“Future pandemic should use pooled strategies from the outset, when testing is otherwise limited.”
Some NHS trusts, including North Devon Healthcare NHS Trust, started using pooled testing towards the start of the pandemic.
The government has been under considerable pressure from scientists and politicians, including former Prime Minister Tony Blair, to adopt the method more widely in the UK.
But it was not until November 24 that the first pilot started, which was explicitly aimed at using the method for student households.
Last September, concerns arose that up to 50 swabs could be tested at once, as Boris Johnson tried to run millions of tests a day.
Researchers say five to 10 swabs should be pooled for each test, and only in asymptomatic individuals.
The UK struggled to get its testing regime off the ground at the start of the pandemic, leaving ministers in the dark about understanding how far the virus was spreading in the country.
At one point, the country was running out of key ingredient for PCR testing, which meant fewer tests could be done.
But in April last year, former Health Secretary Matt Hancock set a target of 100,000 tests per day by the end of the month.
Boris Johnson has invested more than £1 billion in testing launch sites across the country and providing lateral flow testing for every household.
Britain is currently performing nearly 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.