•Experience in managing previous infectious diseases like Ebola, Tuberculosis, Lassa fever comes handy
•Timely lockdown, early surveillance, contact tracing at airports help
•Exposure to similar viruses in the past may be giving relative immunity to people
By Onyebuchi Ezigbo
A new study by a consortium of African medical doctors has given reasons why the COVID-19 pandemic appeared not to have had the catastrophic effect on the health indices in most African countries, as earlier predicted. Factors, such as low population density in cities and communities, large young population, previous experience in epidemic control, and effects of medication used for related diseases in the past, were said to have produced the success rate some African countries have recorded so far.
The findings were contained in a 2020 research journal published by the Nigerian Medical Association (NMA). This is the first comprehensive research by African medical scientific research team to offer scientific explanation why the continent seems to have largely escaped doomsday predictions. Before the publication of the research findings, Western countries have been baffled why Africa with its weak healthcare infrastructure was spared the devastation the COVID-19 wrought on the West.
Africa was a feared destination of the killer coronavirus scourge due to poor health infrastructure heightened by hard-biting economic realities. Predictions by experts and credible organisations, such as the World Health Organisation (WHO), sent warning signals of an impending doom threatening to eclipse the continent should COVID-19 pandemic hit the countries in the region.
But 11 months down the line, absence of exponential growth and low mortality rates, contrary to the experience of other continents and projections for Africa by various agencies, has become a puzzle to many.
The study showed, “Despite weaker health care facilities and systems, the growth of cases in Africa has defied most predictions and has remained geometric and not exponential. Available data and statistics continue to reflect consistently lower numbers than those in other continents, except for the Oceania.
“The severity of presentation has also remained relatively mild and the anticipated overwhelming of the health systems, including the renal services of the various countries on the continent has not been seen. Mortality and case fatality rates have been a fraction of what was predicted.” This, experts maintained, is, however, not a reason to be complacent about the virus because for many African countries, these may still be early days in the pandemic. A change in the pattern might yet occur as the numbers continue to rise.
Besides, it has taken six months to reach the first 500,000 cases but less than two months to cross the million cases mark on the continent.
With an estimated 17.2 per cent of the world’s population, Africa accounts for only five per cent of the total cases and three per cent of the mortality. Mortality for the whole of Africa remained at a reported 19,726 as at August 01, 2020.
The effect of COVID-19 in Africa in terms of spread appears different, when compared to the other continents. The report noted that certain factors might be responsible for the low spread and impact of COVID-19 in the continent.
The research findings showed that experience, rather than resource availability, helped many African countries with previous experience of managing other epidemics, like Ebola, tuberculosis, and Lassa fever, to withstand the spread of COVID-19. These countries were also able to close their airports to international travels much earlier than had been done in other continents.
Similarly, the report showed that prior to the closure of international travel routes, many African countries had commenced disease surveillance activities and contact tracing at the airports, much earlier than was done in many other countries outside the continent.
“All of these factors limited the number of cases ‘seeded’ into African countries, delaying the outset and the subsequent growth in numbers, thereby ‘flattening the curve’ in many of these countries,” the report stated.
The findings also showed that lower number of cases in Africa, as compared to other continents, was attributable to poor testing capacity.
The report said, “This is another major potential reason for the relatively lower numbers of cases on the continent. The number of positive cases reported is driven by the number of rt-PCR tests performed.
“The top five testing countries in the world (as of August 01, 2020) were China 90 million, the USA- 50 million, Russia- 26 million, India- 15 million, and the UK- 13 million. In contrast, the top four countries in Africa were South Africa with 2.9 million tests, Morocco with 1.2 million, Ethiopia with 422,000, and Ghana with 391,000 tests done as at the same date.”
Another key factor limiting the spread of COVID-19 in Africa is population and population density, according to the report. It stated that population density in Africa was much lower than many of the countries in other continents.
The report explained that the disease spread quicker and more easily in crowded, enclosed, and noisy spaces while communities on the continent are mainly rural and widely dispersed, which slows the spread of the virus.
It stated, “The ‘hotspots’ in most countries are the crowded major cities like Lagos in Nigeria (responsible for over 40% of cases), Johannesburg and Cape Town in South Africa, Nairobi in Kenya, and Cairo in Egypt. Within these cities, the greatest numbers are seen in crowded communities such as Kosofe and Alimosho in Lagos.”
The report noted that the lockdown measures in African countries early in the pandemic breakout served to limit the spread of the disease in countries like Rwanda and Senegal, which implemented strict and efficient measures and were able to limit the spread even better than surrounding countries in their sub-regions.
There were speculations of possible relative resistance to the virus with resultant milder presentation and much lower mortality on the continent. This followed a hypothesis that exposure to similar coronaviruses in the past might have conferred relative immunity to patients in Afrca.
Coronavirus cross-reactive antibodies might contribute to a low transmission rate and reduce severity of disease associated with SARS-COV-2 through cross-neutralisation and rapid clearance, experts said.
The report also said the heightened immunity obtained from exposure to previous infections, like malaria and other endemic infections, like tuberculosis and HIV, had been speculated as a possible reason for the milder presentation of the COVID-19 in Africa.
In addition, the study suggested that on-going vaccination for tuberculosis using the BCG vaccine might be a factor in protecting vaccinated individuals from acquiring the illness and when they did, from the severity of the disease and mortality. It said many countries in Africa had continued to vaccinate their citizens against pulmonary tuberculosis with BCG, as the disease remained endemic in various countries on the continent.
Countries in Europe with later discontinuation of BCG vaccination also all seem to have relatively fewer cases and milder illness than their surrounding neighbours, the report observed.
“Although we could not find a correlation with BCG vaccination and the number of coronavirus cases, some studies have shown BCG to be protective against severe cases of the illness,” the study explained.
In the same vein, within the continent, the top testing countries were also the countries with the highest number of cases.
According to the report, antibody testing in several countries suggested that many cases might have been missed by the paucity of tests in the continent. It said many of these tests suggested that as much as 10 per cent to 20 per cent of the population in some of these countries might have already contracted and recovered from the disease.
“In fact, preliminary results from a study from the Western Cape in South Africa revealed a sero-prevalence of antibodies in 40 per cent of antenatal screening specimens and routine monitoring blood tests,” the report added.
Although Africa is the second most populous continent, with an estimated 17.2 per cent of the world’s population, the continent still accounts for only five per cent of the total cases and three per cent of the mortality.
From the onset of the pandemic in Africa, the rate of rise had been slower and the severity of illness and case fatality rates had been lower in comparison to other continents. In addition, contrary to what had been documented in other continents, the occurrence of the renal complications in patients also appeared to be much lower.
The report, apparently the most comprehensive study done on the subject to date, tried to highlight the striking differences between the continents and within the continent of Africa itself and then attempted to explain reasons for the differences.
Case numbers, mortality, number of tests performed, and demographic data were summarised and compared by continents, regions, and countries within the continent of Africa. The research compared all African countries to the top 10 in the world worst hit by COVID-19. It was also able to establish some of the factors that were responsible for the spread of the virus in Africa. For instance, among the African countries, the number of cases in the early stages of the pandemic was directly proportional to the number of international flights into these countries. The busiest international airports on the continent are located in South Africa, which also has the highest numbers on the continent, followed by Egypt, which is also second in case numbers. Countries that exemplified this trend werelike Kenya and Ethiopia, whose airports served as hubs for several countries on the continent and many international travellers passed through their airports and not actually into these countries.
Another category of countries was the ones with infrequent business and tourism contacts with other continents, an these had the lowest number of COVID-19 cases.
Among the African doctors, who carried out the research, are Author affiliations: Ebun L. Bamgboye, St Nicholas Hospital, Lagos; Jesutofunmi A. Omiye, St Nicholas Hospital, Lagos; Oluwasegun J. Afolaranmi, St Nicholas Hospital, Lagos; Mogamat Razeen Davids; Division of Nephrology, Stellenbosch University; and Tygerberg Hospital, Cape Town, South Africa. Others were Elliot Koranteng Tannor; Renal Unit, Department of Medicine, Komfo Anokye Teaching Hospital, Kumasi, Ghana; Shoyab Wadee, Wits Donald Gordon Medical Centre, University of the Witwatersrand, Johannesburg, South Africa; Abdou Niang, Dalal Jamm Hospital, and Dakar Cheikh A. Diop University, Senegal.
There are also Anthony Were, Department of Medicine, East African Kidney Institute, College of Health Sciences, University of Nairobi, Kenya; Saraladevi Naicker, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.