Covid-19 introduced to Africa from abroad, study by leading scientists reveals
IN almost all instances, the earliest introductions of Covid-19 (SARSCoV-2) into individual African countries were from outside the continent .
This is according to a genomic surveillance analysis of SARS-CoV-2 variants in the first year of the pandemic.
The study was undertaken by top scientists from 112 African and 25 international organisations in close collaboration with the Africa Centres for Disease Control and Prevention (Africa CDC) and the World Health Organization (WHO), and published in Science.org recently.
“Our phylogeographic reconstruction of past viral dissemination patterns suggests a strong epidemiological linkage between Europe and Africa, with 64% of detectable viral imports into Africa originating in Europe and 41% of detectable viral exports from Africa landing in Europe.
“This phylogeographic analysis also suggests a changing pattern of viral diffusion into and within Africa over the course of 2020,” the authors said.
However as the pandemic progressed, there was then a shift in the dynamics, the authors found, “with an increasing number of importations from other African countries”.
South Africa, Kenya and Nigeria appeared as major sources of importations into other African countries.
“Particularly striking is the southern African region, where South Africa is the source for a large proportion (~80%) of the importations to other countries in the region.”
In total, they detected at least 757 viral introductions into African countries between the start of 2020 and February 2021, over half of which occurred before the end of May 2020.
Analysis of the B.1.351 (Beta) lineage revealed that in the final months of 2020, the variant spread from South Africa into neighbouring countries, reaching as far north as the DRC by February 2021.
This, the authors found, may have been facilitated through rail and road networks that form major transport arteries linking South Africa’s ocean ports to commercial and industrial centres in Botswana, Zimbabwe, Zambia and the southern parts of the DRC.
“The rapid, apparently unimpeded spread of B.1.351 into these countries suggests that current land-border controls that are intended to curb the international spread of the virus are ineffective,” the researchers state.
While, Africa accounted for a relatively low number of reported cases and deaths, “emerging data from seroprevalence surveys and autopsy studies in some African countries suggests that the true number of infections and deaths may be several fold higher than reported”.
The authors emphasised that Africa must not be left behind in the global pandemic response, otherwise it could become a source for new variants.
WHO regional director for Africa, Dr Matshidiso Moeti said the Delta variant was a “wake-up call” in terms of the importance of genomic information.
“We ignore mutations and variants at our own peril.’’