Africa’s daily count of new coronavirus cases has soared as the more contagious Delta variant drives an aggressive third wave of infections through a population largely unprotected by vaccines. The continent’s daily tally of new cases has increased for seven weeks in a row, surging more than 20% in the past week alone to reach 46,528 by July 9, according to Our World in Data.
The million-dollar question is why is the virus once again ripping through Africa’s population, despite the large proportion of people who have previously been infected? A recent study by South Africa’s National Blood Service found that 47.4% of the blood donor samples analysed between January and May 2021 contained SARS-CoV-2 antibodies, signalling prior infection with the virus that causes Covid-19. “We should have a significant number of people who are protected. But emerging data shows even though people may have been previously exposed to Beta (or other variants), they may be susceptible to Delta. That is a big concern,” says Koleka Mlisana, head of academic affairs, research and quality assurance at the National Health Laboratory Service in South Africa.
A laboratory study published last week in Nature found Delta variant was better at escaping antibodies made in response to natural infection with the Alpha variant, and local scientists have flagged similar concerns about potentially limited protection conferred by prior infection with Beta. The Delta variant was first identified in India last October and has now been detected in more than 100 countries, including many in Africa.
There is as yet no data to suggest Delta causes more severe illness than other variants, but recent research by the National Institute of Communicable Disease (NICD), published in The Lancet, drew attention to the risk to patients when cases surge and hospital services are overwhelmed. This risk may well play out in Nigeria where doctors are already reporting rising hospitalisation in cities like Lagos.
After the country’s first two waves, Nigeria saw a slide backwards to super-spreader events. When you have increased transmission especially in the case of Delta, you are likely to see a lot more infections. For instance, Beta is estimated to be 50% more transmissible than the original coronavirus lineage detected in Wuhan, China, while Delta is 60% more transmissible than Beta.
Recent UK data shows full vaccination with the Pfizer-BioNTech shot confers 96% protection against severe illness and death from Covid-19 caused by the Delta variant. When Nigeria’s much delayed vaccination drive happens it will be too late to prevent a third wave.
