‘Why has the third wave been more deadly than first and second waves?’
According to a study by the SA National Blood Service 47.4% of the blood donor samples analysed between January and May contained SARS-CoV-2 antibodies, showed prior infection with the virus that causes Covid-19. – Business Day (14 July 2021)
The latest data shows that, even people who have been previously exposed to Beta (or other variants), may be susceptible to Delta. A laboratory study published last week in Nature found Delta 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 evolution of SARSCoV-2 into the Delta variant, with its increased transmissibility and apparent ability to evade antibodies generated by prior infection, combined with a hefty dose of Covid-19 fatigue and marginal vaccine coverage, has created a perfect storm, according to Marc Mendelson, head of the division of infectious disease and HIV at the University of Cape Town.”