Johannesburg - New data from the SA National Blood Service (SANBS) has shed light on why the virus may be devastating Gauteng during the third wave.
The SANBS released preliminary results from the analysis of new data from a survey of blood donors in all provinces on Sunday. The survey was conducted to determine the prevalence of antibodies against Sars-CoV-2, the virus that causes Covid-19.
Antibodies are produced in response to infection, and remain detectable, in the vast majority of people, for at least a year, said the SANBS.
The study, in partnership with the Western Cape Blood Service, the national Department of Science and Innovation, the National Research Foundation and the SA Centre of Excellence in Epidemiology Modelling and Analysis, is one of the few ways of probing the extent of Sars-CoV-2 infection at the population level.
The analysis is mainly based on sampling done in May, essentially before the emergence of the third wave. SANBS medical director, Dr Karin van den Berg, said the research team also conducted interviews with a subset of donors who tested positive and negative for Covid-19.
“This analysis indicates, as expected, that a small proportion of donors who have been formally diagnosed with Covid-19 did not, at the time of their donations, have detectable levels of antibodies, and a large majority of those donors who had detectable levels of antibodies were never diagnosed as being infected.”
Van den Berg added that some of this additional data had only just been collected and will be further examined for patterns of clinical diagnosis as well as self-reported symptoms.
“Interestingly, we saw comparatively very low antibody levels among donors who presented in Gauteng compared with other provinces, especially when you consider population density.”
Van den Berg said this could indicate that Gauteng was more insulated from the initial waves of the virus and this may in part explain the spread of the virus through Gauteng.
“However, the role of the different variants, especially the Delta variant must also be considered.
“Further investigation would be required to more fully explain the dynamics of the third wave.”
The Star