Containing Covid-19 requires testing of individuals and isolating those who test positive, together with recent contacts, to prevent further spread and it is therefore critical to ensure that testing is independently verified to assure its accuracy.
Given the urgent need to ramp up testing, a team from the University of the Witwatersrand’s (Wits') Centre for Biomedical Tuberculosis Research (CBTBR) has developed a unique “control standard” to undertake this for certain diagnostic testing platforms.
The team says that what makes it unique is that it uses biomimicry, which is considered to be a safer alternative to incorporating the actual Sars-Cov-2 virus.
The Wits team, headed up by Professor Bavesh Kana, used this biomimicry technique to engineer a control organism that mimics the genetic material of the virus when used in diagnostic tests kits.
If the tests work correctly, the genetically modified organism is identified as being Sars-Covid-2.
It can be rapidly deployed in a range of settings – from central laboratories to clinics across the country.
In contrast, viral-based controls require specialist shipping and handling procedures and the need for highly skilled staff and infrastructure, the team points out.
Kana notes that accuracy testing controls are central to the deployment of any successful diagnostic test.
“The virus continues to spread viciously across countries, with infections again rising rapidly across Europe and North America.
"In order for governments to halt its spread, reliable tools with verifiable results are of utmost importance. Without appropriate controls to report whether tests are delivering the correct result, diagnosing and effectively managing Covid-19 will be very difficult, if not impossible,” he informs.
The pandemic has put healthcare systems across the globe under immense pressure, particularly on the issue of rapid diagnostic test development and implementation. Specific sections of the DNA are typically the targeted molecule for diagnosing bacteria and viruses.
With certain viruses like HIV and Sars-Cov-2, the genetic material is contained in the RNA, and consequently diagnosis relies on the detection of the Sars-Cov-2 RNA.
Recognising the gap in the verification of Covid-19 tests obtained through molecular diagnosis tools, and understanding the risks and complications of using the live virus, Kana and his team, which includes Dr Edith Machowski, Dr Bhavna Gordhan and Dr Christopher Ealand, developed control standards for diagnostics tools used in the testing of the Covid-19 virus.
Having previously contributed to the development of biomimicry-based control standards for diagnostics for drug-resistant tuberculosis (TB), which are now deployed in more than 20 countries, the team embarked on a fast-tracked research programme to develop the Sars-Cov-2 diagnostic control as early as February.
“As Sars-Cov-2 is an RNA virus, the biomimicry process was not straightforward as compared to TB. This is due to the inherent instability of RNA.
"However, we have been able to include elements to produce a control that mimics the diagnostic profile of Sars-Cov-2, which is stable, effective and a safer alternative to using the live virus,” says Machowski.
Previous controls developed by Wits have been commercialised through a spin-out company SmartSpot Quality.
“Through our development and rollout of packaged controls for diagnostics for TB, SmartSpot is well geared to package the bulk stock of Covid-19 controls in its Wits-developed control cards.
"Under licence to Wits, we will drive the roll-out of the controls and the ongoing external quality assessment programme,” informs SmartSpot MD Dean Sher.
The new controls are now deployed in the National Health Laboratories’ testing programme.
“We are grateful for the opportunity to contribute to the Covid-19 testing efforts within the country, and internationally, enabled by the support provided by Wits and funders including the National Research Foundation, the Department of Science and Innovation, the Technology Innovation Agency, the South African Medical Research Council and the Innovation Support Unit at Wits Enterprise,” acclaims Kana.