As Africa awaits the surge in coronavirus cases seen in Europe, Asia and the U.S., research groups around the globe are working on new technologies focussed on combating the pandemic. New rapid testing kits developed in Ghana and Senegal seem a promising breakthrough to help African countries cope.
Until a vaccine is developed and made available, large-scale testing has been unanimously recommended by virologists as a key strategy in the fight against coronavirus. Testing provides vital information regarding the spread of the disease, enabling governments to take the necessary steps to break the chain of transmission.
Widespread testing is proving difficult in many countries, whether that be due to ineffective organisation or lack of resources. This is even more of a problem in Africa, where some healthcare systems are weak, sanitation is poor and testing facilities are sparse.
The current commonly used method of testing detects the presence of the SARS-COV-2 virus that causes COVID-19. The viral genetic material is amplified to a detectable level using PCR which requires technical training and expensive equipment. This form of testing takes up to 48 hours to return results; of which potentially 30% are false negatives, most likely due to inadequate sampling from the patient’s airways. This means the spread of coronavirus in these countries could be worse than the statistics suggest.
For widespread testing across Africa, a low cost, point-of-care kit is needed and recent developments in Ghana and Senegal may have found a promising solution.
Collaboration between the Kwame Nkrumah University of Science and Technology (KNUST), Incas Diagnostics, and the Kumasi Centre for Collaborative Research (KCCR) has led to the development of a rapid COVID-19 testing kit in Ghana. This test kit uses a finger-prick blood sample to detect a patient’s immune response to SARS-COV-2, providing a positive or negative result in 15-20 minutes.
When a patient is infected with the SARS-COV-2 virus, their white blood cells secrete Y-shaped molecules, known as antibodies, that specifically bind to the outside of the virus particle. Once bound, these antibodies recruit other white blood cells that can destroy the virus. Antibodies can remain for a long time after an infection has been cleared, providing the patient with immunity against the disease. However, it is currently unknown how long the antibodies against SARS-COV-2 last. Furthermore, it can take some time for the body to produce antibodies that successfully bind to the virus, meaning an infection can cause a great deal of harm before the immune system has evolved to fight it off.
The specific binding mechanism of antibodies makes them a suitable target for detecting an immune response in a patient and this is what KNUST and Incas Diagnostics have utilised.
One of the main benefits of antibody tests is that they can be used to diagnose asymptomatic cases and those that have recovered from a previous infection, identifying a proportion of the population with immunity. These people could work safely on the frontline and possibly donate antibody-rich serum to treatment programmes for critical patients.
The lateral flow-based kits also require minimal equipment and technical training, providing a promising answer for testing in countries with weaker healthcare systems and rural communities with fewer resources.
However, just like the PCR method for COVID-19 testing, there are some limitations associated with the rapid diagnostic kits. For example, antibodies are only detectable at least seven days after infection, leaving a time window in which false negatives may occur. Antibody testing kits developed by other research groups have also lacked accuracy when tested by independent laboratories.
Professor John Newton, leading the UK’s testing programmes, stated “[they] had been able to identify antibodies in patients who had been seriously ill with coronavirus but didn’t pick up the milder cases”.
The Pasteur Institute in Senegal, who has previously worked on yellow fever and dengue vaccines, has also developed a rapid COVID-19 testing kit using similar antibody-based technology.
The test kit prototype has been produced in collaboration with Mologic, a British biotechnology company co-founded by the creator of the Clearblue pregnancy test. Like the kit developed in Ghana, this 10-minute COVID-19 test uses either a saliva swab or blood finger prick sample to detect antibodies against SARS-COV-2.
Mologic’s website states their mission is “to make high quality diagnostics affordable and accessible on the global market” and Joe Fitchett, the Medical Director, has said that their rapid test kit would be sold at cost-price (approximately $1) thanks to generous grants from the Bill & Melinda Gates Foundation and the UK Government.
Both rapid testing kits are being assessed by independent laboratories and are awaiting government accreditation. If an affordable, point-of-care diagnostic tool can meet regulatory standards for widespread use, it could have a huge impact on Africa’s fight against coronavirus.
