INTRODUCTION
Coronavirus infection caused by SARS-CoV-2 strain was identified in 41 hospitalized patients in Wuhan, Hubei province, in China in December 2019.(1,2) In addition, New Generation Sequencing revealed that the virus was different from the SARS-CoV which caused severe acute respiratory syndrome in 2003.(3) In March 2020, WHO declared this infection, which was named Coronavirus disease-19 (COVID-19), a global pandemic as the infection rapidly spread around the world. At the time of writing (01/10/2020), Africa Centers for Disease Control (CDC) had recorded 1,481,225 COVID-19 cases with 36,143 deaths in Africa (Figure 1). SARS-CoV-2 virus has tropism for the respiratory system and causes a spectrum of clinical presentations spanning from mild symptoms to adult respiratory distress syndrome (ARDS).(4) The underlying pathogenesis is thought to be due to cytokine storm which is a result of secretion of numerous pro-inflammatory cytokines and chemokines such as IL8, IL6, IL9, IL10 amongst others.(5–7) Excessive secretion of cytokines results in multiorgan damage in some patients including acute kidney injury (AKI) and ARDS. The pathogenic mechanism resulting in kidney damage remains unknown. Single-cell RNA sequencing revealed that ACE2 is expressed in the cells of lungs, colon, ileum, and kidney.(8–10)It is worth noting that SARS-CoV-2 is detected in urine, blood, anal swab and oropharyngeal swabs.(11) As a result, SARS-CoV-2 can affect the respiratory system, haematological system and urinary system and this is in keeping with the clinical features of COVID-19. Molecular studies indicate that SARS-CoV-2 uses ACE2 and TMPRSS2 to gain entry into the cell and that ACE2 and TMPRSS2 genes are highly co-expressed on podocytes and proximal tubular cells of the kidneys.(10) ACE2 expression is a 100-fold higher in kidney tissues compared to the lungs. As a consequence, the ACE2 dependent pathway is a likely means by which SARS-CoV-2 infects the kidneys more severely than the lungs. However, existing clinical evidence shows more lung than kidney involvement.
COVID-19 ONSET IN AFRICA
Africa was the last continent to experience the coronavirus pandemic but expected to be the most vulnerable continent to be affected by COVID-19.(12) The African continent confirmed its first case on 14th February 2020 in Egypt and in sub-Sahara Africa, the first patient was diagnosed in Nigeria on 27th February 2020 which was an imported case from Italy.
PREPAREDNESS
There was early recognition that African populations would be at increased risk from COVID-19 infection because of inadequate health services, increased prevalence of infections such as HIV, malaria and tuberculosis and the lack of an infrastructure for viral testing.(13) The response to the COVID-19 pandemic was led by governments and was multi-sectoral and multi-agency. At the level of the African Union, the response to COVID-19 infection was led by the African CDC which activated an Emergency Operations Center for COVID-19 on 27th January 2020 and initiated meetings with the WHO and African Region of WHO, regional collaborating centres, ministries of health and national public health institutions. The priorities at the time for defining policy in terms of containment and/or mitigation, development of capacity for training, testing, supply of personal protective equipment and others have been reported by the African CDC.(14)
INFRASTRUCTURE, HUMAN RESOURCE AND TESTING CAPACITY
In the early days of the pandemic, Africa experienced difficulties in the ability to test, detect, isolate and treat. This improved after local authorities increased testing capacity and was also aided by the donation of testing kits from international and local donors. There were problems in terms of infrastructure, equipment, trained human resources and reagents. The Africa CDC led African Task Force for Coronavirus Preparedness and Response (AFTCOR); a coalition between the African Union (AU), AU member states, the WHO Regional Office for Africa, and other stakeholders was instrumental in scaling up the testing capacity.(15) Also, AFTCOR in conjunction with the South African National Institute for Infectious Diseases, the Senegalese Institute Pasteur of Dakar, and the West African Health Organization trained scientists for molecular detection of SARS CoV-2.(15) Furthermore, there have been many local efforts by African countries to strengthen their infrastructural base to fight the pandemic. For instance, with support from the local private sector, Ghana was able to build a fully equipped infectious disease centre within a few months.(16) There has been an increase in molecular testing across the continent, especially leveraged on existing molecular diagnostic capacity for other diseases like HIV and tuberculosis to enhance the testing capacity for SARS CoV-2 infection.(15)
In view of the limited diagnostic capacity, countries like Ghana are using pooled testing of COVID-19 samples, thus limiting the duration of processing time and increasing sample testing.
Nevertheless, with the rising incidence of SARS CoV-2 across the continent, the current test rate is inadequate and there has been ongoing anxiety that the already weak health systems will be overwhelmed. According to the Africa CDC, the continent needs 15 million testing kits but Africa
CDC can only provide 1 million. This will pose a real challenge for Africa in fighting the COVID-19 pandemic. There is a need in Africa for cost-effective ways of testing and managing this pandemic. An ideal test should be cheap, accurate and easy to use. Most of the tests currently have only one of these properties. There is a need to choose a test whose strengths and limitations are aligned to the needs of specific populations and also that which is affordable. For most African countries the test must be sensitive and specific enough to be clinically relevant and affordable by most developing countries. The nucleic acid tests being used by most African countries now are too complex and expensive. It is recommended that low-cost antigen test is the way forward for most African countries. Governmental and non-governmental health agencies and other stakeholders should consider antigen-based testing to fight COVID-19 as it is affordable and scalable across the continent, especially in the remote villages where the virus may go undetected.
EFFORTS TO CONTROL THE PANDEMIC
The majority of African countries quickly implemented lockdown measures which may have impacted positively on how well these countries fared during the early phase of the COVID 19 pandemic.(17,18) African leaders may have learnt from the slow response of other affected regions outside the continent. Thus, by April 2020 most African countries had implemented policies geared towards early control of the spread of SARS-CoV-2 infection. Countries in West Africa which experienced the Ebola outbreak were well-positioned to face the COVID 19 pandemic based on their previous experience with the Ebola virus epidemic.(19)
Most sub-Saharan African countries put drastic measures in place such as closing down borders, intensifying social distancing methods, enforcing mandatory use of face masks in public places and reducing public events and gatherings. In addition, there was rapid implementation of public health measures across the continent. A significant number of countries implemented self-isolation of exposed people and created centres for quarantining suspected and confirmed cases. As these measures are put in place, it is expected that the curve will flatten bearing in mind the weak health systems and the high prevalence of co-morbid conditions in Africa.
PREVALENCE OF COVID-19 IN AFRICA
Compared with Europe and the Americas, the rate of doubling of COVID-19 cases and the likely peak of projected infections has been lower in Africa. (Figure 2) There was significant heterogeneity between African countries in the trajectory of increase of COVID-19 infections and the level of infections (Figure 3).
COVID-19 cases globally.
Global trajectory of COVID cases by continent. The rate of increase of COVID-19 cases is lower in Africa than in Europe, the Americas and Asia. https://covid19forecast.science.unimelb.edu.au/#about.
Trajectory of COVID-19 cases in African countries. https://covid19forecast.science.unimelb.edu.au/#about
COVID-19 STATUS IN AFRICA AUGUST 2020
By the end of August 2020, Africa was beginning to see a reduction in new COVID-19 cases and COVID-19 related deaths. The WHO Africa Region External Situation Report of 16th September (20) reported a 14% decrease in incident cases and a 22% decrease in incident deaths as compared with the report of 2 August–8 September 2020.
HEALTHCARE WORKERS
There has been a heavy price paid by healthcare workers in Africa from COVID-19 infection. As of 26th August, 39,192 (4.2%) of all infections were in healthcare workers (20) and there was a substantial mortality.
TREATMENT FOR COVID-19
A review of the efficacy of treatments of COVID-19 is beyond the scope of this review. It is important to give anticoagulant treatment in patients with COVID-19 infections. The outcomes of treatment trials of anti-interleukin 6 antibodies and of convalescent plasma are awaited. In a meta-analysis of 7 randomized clinical trials of 1703 critically ill patients with COVID-19, patients who were randomized to steroids (dexamethasone, hydrocortisone or methylprednisolone) were less likely to die (228 out of 678) when compared with patients given usual care or placebo (425 out 1025) OR;0.66 95% CI: 0.53–0.84.(21) In another meta-analysis, Remdesivir reduced the duration of symptoms (22) and hydroxychloroquine did not reduce the risk of death or mechanical ventilation.(22)
LOWER MORTALITY OF COVID-19 IN AFRICA AS COMPARED WITH EUROPE AND NORTH AMERICA
The Case Fatality Rate (CFR) across Africa is around 3–5%,(23) and this is lower than in some countries in Europe where the CFR is as high as 15%. The decreased severity and lower mortality of COVID-19 in Africa as compared with Europe and North America and elsewhere are difficult to explain. One probable reason is the younger age of the population in Africa. The median population age in Africa is 19.7 years compared with 38.6 years in the United States.(24)
Nevertheless over 33,000 deaths have been reported in Africa, thus COVID-19 is not a benign illness.
In the response to SARS-CoV-2 infection, an effective adaptive immune response can limit disease severity whereas unrestrained activation of innate immune cells can lead to a cytokine storm and severe disease.(24) It has been reported that stimulation of pattern recognition receptors of the innate immune system in South African children was associated with lower levels of most cytokines as compared with children from Belgium, Ecuador and Canada.(25)
The observation of impaired innate immune responses in African children does not provide a ready explanation for protection from COVID-19 infection. One would have predicted that immunosuppression associated with HIV infection would have increased mortality from COVID-19 infection. Despite the likelihood of incomplete case ascertainment and the inadequacy of testing, African healthcare systems have not been overwhelmed by COVID-19 infection. To date there do not appear to be any differences between the clades of SARS-CoV-2 from Africa and other parts of the world. Furthermore, African-Americans in the United States have a high susceptibility of developing and succumbing from COVID-18 infection, thus the suggestion that African genomes protect against SARS-CoV-2 is implausible.(24)
SECOND WAVE OF COVID-19 INFECTION IN AFRICA
While Africa has suffered immensely from the COVID-19 pandemic, its health effects have not been as catastrophic as predicted. We are now witnessing second waves of COVID-19 infections around the world, and there is no reason to assume that Africa will be immune to this. Therefore, it is critical to maintain the infrastructure that has been built up to manage the pandemic. There is also anxiety that, a second wave of COVID-19 infection in Africa may not be as benign as the first one.