Scientists have achieved a breakthrough in sampling wastewater to detect changes in COVID-19 infections within large communities.
The new method is capable of identifying the coronavirus within wastewater samples and tracking whether infection rates are growing or shrinking.
Wastewater is a “robust source” of COVID-19, according to researchers, because infected people shed the virus in their stool, meaning large amounts of virus particles are flushed down the toilet.
Flushing the loo can create a cloud of virus particles which the next user might inhale, warns study
“This work confirms that trends in concentrations of SARS-CoV-2 RNA in wastewater tracks with trends of new COVID-19 infections in the community,” said Professor Alexandria Boehm, of Stanford University.
“Wastewater data complements the data from clinical testing and may provide additional insight into COVID-19 infections within communities,” added the professor, who is co-senior author of the research.
The breakthrough comes as the US faces record levels of daily transmissions, posing a significant challenge for public health authorities attempting to manage the virus.
Tracking the virus is proving problematic due many people with mild cases, or who are asymptomatic, going undetected – and those who do get tested can spread the virus before they receive their results.
More from Covid-19
COVID-19: Footfall at shopping centres well below 2019 levels – despite England’s lockdown ending
COVID-19: England cricket tour of South Africa abandoned after positive virus tests
COVID-19: Britons back air travel ban for people who’ve not received coronavirus vaccine, poll suggests
COVID-19: William and Kate arrive in Edinburgh on first stop of UK Royal Train tour
COVID-19: Pfizer/BioNTech vaccine could be airlifted to UK if Brexit trade talks collapse
Helen Mirren: COVID pandemic could leave theatre workers homeless
“Faster identification of case spikes could allow local officials to act more quickly before the disease reaches a crucial tipping point where transmission becomes difficult to contain and hospitalisations overwhelm the local health system,” said Stanford.
To advance the science of wastewater surveillance for COVID-19, the researchers focused on detecting the virus in the settled sediment rather than the liquid influent.
They found they were able to find higher concentrations of the virus in the solid samples than in the liquid ones, giving a better indication of infection rates throughout the population.
The research has the potential to be used in areas which lack the resources for individual clinical testing, as well as to be used by school districts to see if the virus circulation is decreasing.
A new pilot is being launched this month to sample up to eight wastewater treatment plants within California daily, with a 24-hour turnaround time for results.
It follows the publication of a paper by the UK Scientific Advisory Group for Emergencies (SAGE) about the use wastewater-based epidemiology in the UK.
The paper reported that detecting the coronavirus RNA in wastewater “has rapidly become a significant tool to address the ongoing pandemic” and is being used across the country.
The SAGE paper revealed how wastewater testing uncovered an isolated outbreak of COVID-19 from a vessel docked at the Devonport dockyard in Plymouth that hadn’t been included in the reported Test and Trace numbers.
Similarly, at Orkney sewage treatment works – which serves a population of roughly 7,750 people – the virus was detected in the wastewater despite fewer than 10 positive cases being recorded in test numbers – allowing Public Health Scotland to be notified.
The researchers say they are working with local health and academic stakeholders in Exeter to see if wastewater surveillance can be used to monitor outbreaks in areas where there are a high proportion of asymptomatic individuals, such as universities.
Please use Chrome browser for a more accessible video player
Last Thursday, the US reported more than 3,100 coronavirus-related deaths in a single day – a record for the country – which meant more people died with COVID-19 in that single day than in the 9/11 terrorist attacks.
President-elect Joe Biden said on Saturday he will not force Americans to take any vaccine – but did warn the country faces a “bleak future” unless swift action is taken to agree on a coronavirus aid bill.
His comments come as the country is engulfed in a nationwide spike in cases that is hampering its economic recovery.
Mr Biden also expressed concern that so far he has seen “no detailed plan” from the Trump administration on how to distribute an approved coronavirus vaccine.