A number of the College’s staff are taking part in volunteering schemes in support of the communities in which we operate during this difficult time. Among them are scientists Dr Kerensa Ogbe and Dr Rebecca Moore who have been working with Systems Biology Laboratory UK (SBL) who are offering free COVID-19 testing to NHS staff who are on the frontline fighting the virus.

The Bradfieldian spoke to both scientists about their experiences as part of the Volunteer Testing Network.

Dr Ogbe worked as a research scientist with South Oxfordshire based SBL for six years prior to becoming a teacher and knew they had been involved with Ebola testing a few years ago. “I know how altruistic they are, so I contacted them a week or so before lockdown to ask if they were involved with COVID-19 at all. They replied saying ‘you know us too well!’ and explained that they had put their research programme on the back burner to concentrate solely on offering free COVID-19 testing to NHS staff from GP surgeries in South Oxfordshire. I then volunteered to help out if they needed any more hands in the lab. I told Dr Moore about it and asked if she wanted to be involved as well.”

Together, the scientists have been part of the team who are testing GPs, nurses and receptionists; anyone who is currently working in the NHS surgeries in the area. SBL are covering every GP surgery in South Oxfordshire amounting to some 300 NHS staff providing frontline healthcare for approximately 150,000 people across the county.

Dr Moore states that their aim is to keep expanding to offer more testing across the region. “Over the past few weeks, we have been testing all employees at the majority of GP surgeries around South Oxfordshire and a few in West Berkshire and have begun to branch out to community carers. The hope is to eventually cover every GP surgery in South Oxfordshire and as many care homes as possible.”

Different tiers of testing are on offer, some weekly, some bi-weekly and some tri-weekly, depending on the requirements and capacity of the lab. Anyone who tests positive self-isolates and can then come in for drive-through swabbing to be routinely tested until they become negative again before going back to work.

It is not only the safety of the NHS staff being tested that needs to be considered but also the safety of those in the volunteer network. PPE is critical and all volunteers wear a lab coat, two sets of nitrile gloves, the outer pair being elbow length, and have face shields but the safety steps go well beyond personal equipment.

“No-one is allowed to start work until we have done a drive-through swab and it has been confirmed negative,” says Dr Ogbe. “No-one else is allowed into the office/lab space unless they have been tested and show up negative. All samples taken are delivered in sealed biohazard bags and each swab is in its own sealed container. We work in Class 2 laminar flow hoods which provide essential protection from contamination via a combination of inflow and downflow air and filters. The use of the laminar flow hoods was risk-assessed prior to testing and they were so safe that the use of PPE with them became an additional option.”

“At the beginning we were processing approximately 80 – 100 samples per day,” says Dr Moore. “We really wanted to do more but we have been restricted by a national shortage in swabs. We have since been able to move into a new phase, where we can test both staff and residents at local care homes. This is incredibly important as people living in these environments find it very difficult to socially distance or self isolate. This way we can catch anyone who is beginning to develop the virus early and get them isolated and treated as soon as possible. Already we have detected some asymptomatic residents, who would have been spreading the virus unknowingly, but now they are isolating and protecting their friends and carers. This is particularly exciting, as there have not been any documented cases of asymptomatic individuals in the elderly community to date.”

For any budding Bradfield scientists who want to know more about the science behind testing, Dr Ogbe goes into detail about what each test involves, why they use an RNA test rather than a DNA test and how they ensure the tests are accurate.

“Each test involves taking a buccal swab (from the back of the mouth) which will then hopefully contain some of that person’s cells. The swabs are then manually processed in the lab.

First the RNA is isolated from the cells and then it is purified and concentrated. It is an RNA test because COVID-19 is an RNA-containing virus. Some viruses contain DNA and others RNA.

The RNA that has been extracted is then subjected to something called real-time RT-PCR which basically uses things called primers to bind to known sequences of RNA, which can then be amplified in a machine, effectively by making multiple copies of them to bring them to detectable levels.

The COVID-19 test we are running was developed by the Centre for Disease Control and uses several sets of primers. Two of these are designed to bind to different sections of the nucleocapsid ‘N’ gene which is part of the COVID-19 RNA inside each virus. The third set of primers is designed to bind to a human gene called RNase P, this acts as a quality control, as if human cells have been swabbed and processed correctly then this gene should show up positive.

If the RNase P gene doesn’t show up as positive, you know something has gone wrong somewhere, either the swab wasn’t taken correctly, or RNA wasn’t isolated correctly, as all human cells should contain this RNA.

The kit also comes with a non-infectious COVID-19 viral control and a human RNase P control RNA, which should be run with every test panel and should always show positive with the primer sets and probes supplied.”

Mike Fischer (Fischer Family Trust) and Nick Parkinson (Head Scientist, SBL) have been working tirelessly setting up a UK-wide network to try to support more small labs to start testing in their local areas. They have set up a website where people can go to find out what equipment they need or for GPs to sign up their local surgery. For more information visit www.covid19-testing.org/

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