Also see the video conversation between the author of this piece and MedPage Today Editor-in-Chief Marty Makary, MD.
The novel coronavirus SARS-CoV-2 came to attention in Wuhan, China, in December 2019 and has since marched across the world, resulting in nearly 36 million infections and over a million deaths, according to the Johns Hopkins Coronavirus Resource Center. The specter of another deadly viral pathogen raised alarm throughout an African public health community scarred by the history of the AIDS pandemic, Ebola outbreaks, and other devastating infectious diseases.
These fears arose from two fundamental observations. First, African populations are medically vulnerable. Kenya, where I live and work, is home to 1.5 million HIV-infected individuals, one of the largest epidemics in the world. The incidence of tuberculosis is 558 per 100,000 people annually; only about 40% of these cases are detected. Hundreds of thousands have recovered from tuberculosis and live with some degree of lung sequelae. In Nairobi’s largest informal settlement, nearly half the children are stunted by malnutrition. Approximately 150,000 Kenyans have rheumatic heart disease, most lacking access to curative services. Hypertension, long considered a disease of affluence, is actually quite common.
The second major concern was the fragility of Africa’s healthcare systems. The paucity of oxygen and intensive care meant the seriously ill would not receive necessary treatment. Only half of African hospitals, and 20% of all health facilities, possess oxygen in any form. Most of the oxygen that is available comes in cylinders. Cylinder oxygen is inadequate to support patients with clinically severe COVID-19. Even the largest cylinder containing 9,000 liters of oxygen would only last 10 hours if a patient required 15 liters per minute via a non-rebreather mask. The cost, limited supply, and transport challenges preclude using two to three large cylinders of oxygen for one patient each day. Few hospitals host large oxygen generating plants supplying the piped oxygen taken for granted in the West. During my last week working on the COVID-19 ward of a relatively well-resourced referral mission hospital, just four coronavirus patients consumed over a quarter of the facility’s oxygen capacity. Use of 50-70 liters per minute of high-flow nasal cannula, required to save the sickest patients, would exceed the capacity of many hospitals that do possess piped gas.
My own assumptions incorporated these concerns and were no doubt influenced by the experience of having lived through the peak of the African AIDS crisis. An out-of-control epidemic would tear through Kenya’s informal settlements, devastating vulnerable communities. South Africa suffers from high rates not only of HIV and tuberculosis but also obesity and diabetes, and its population, much younger than the U.S., is often concentrated in densely packed urban settlements. These factors would seem to make the continent ripe for catastrophe from COVID-19.
Yet this calamity did not arrive in Kenya or the rest of Africa (outside South Africa), although cases have begun to rise again in Kenya as of this writing. Even allowing for under-reporting, death rates have been low. Granted, at the peak of the “surge,” my hospital neared its COVID ward capacity and prepared to turn away patients due to oxygen scarcity.
This eventuality never came to pass. In a country of over 50 million people, Kenya has recorded 743 deaths. Subsequent surveys of excess deaths may increase this figure, but the number appears to be an order of magnitude below initial fears. Following a peak in July, the caseload rapidly abated. A group of Kenyan epidemiologists predict a “long-tailed decline.”
Other African countries have experienced similar trajectories. The question now for clinicians and policymakers is why Africa avoided these dire scenarios. The question is especially pertinent as economies and borders reopen and tourists are welcomed from ongoing viral hotspots in the West.
One obvious explanation is that the government of Kenya acted quickly to educate the public, issue a mask mandate, and enforce mitigation measures. Travel between Nairobi and outlying counties was restricted. Schools, restaurants, and bars closed, and a curfew was imposed. Inbound international flights were canceled. Perhaps Kenya just did not receive the “loading dose” of infected travelers that America did, or the enactment of robust contact tracing limited community spread.
While these measures no doubt had an effect, the same group of epidemiologists mentioned above estimated that by early August at least a third of residents in the two large cities of Nairobi and Mombasa had already been exposed. This finding is consistent with the prediction that the easily transmissible SARS-CoV-2 virus would rapidly wend its way through the Kenyan population. Despite this high infection rate, deaths and severe illness were limited. During the peak, key government referral hospitals admitted hundreds of patients, but the kind of widespread misery feared by national and international public health leaders did not materialize. The system, as fragile as it is, did not break.
My own conclusion is that three factors were more salient than concerns about an inadequately equipped health system:
1. Kenya and other African nations are very young. Kenya’s median age is 20 years. Malawi’s is 17. The implication is that the right-sided tail is short. Only 3% of Kenyans are 65 years of age or older. The comparable figure in the United States is 17%. When my father, who has silver hair, visited our family in Malawi at the age of 74, a young Malawian colleague exclaimed, “How old are you?” He was 74 at the time. “Wow! Almost nobody in Malawi is that old.” Additionally, older Kenyans tend to move out of cities to retire in ancestral villages “up country,” where population density is lower. Africa has few nursing homes.
In retrospect, we should have understood age distribution as Africa’s great shield against SARS-CoV-2. Italy had already been hit hard in March. The data demonstrated that death and severe disease were very heavily concentrated in older populations. With infection fatality rates orders of magnitude lower than those suffered by the elderly, very young African populations are expected to experience low death rates. The evidence was staring us in the face. Well-resourced clinical health systems can mitigate but not overcome uncontrolled epidemics among the elderly. Conversely, young populations can withstand SARS-CoV-2 despite limited resources. This outcome is starkly different from the 1918 influenza pandemic, which more heavily impacted the young and killed an estimated 1.8% of Africa’s population.
2. Africa’s spectrum of comorbid conditions differs from the West. We worried that the large HIV-infected population, even those stable on antiretroviral therapy (ART), would experience a heavy burden of COVID-19 disease. Data from South Africa show that the adjusted odds ratio (OR) for death is elevated at 2.1. Concerning, to be sure, but not the catastrophe anticipated. In the same study, the adjusted OR for death from COVID-19 in patients with diabetes ranged from 5 to 12 depending on the degree of glycemic control.
Even among the few HIV-infected patients, I cared for with severe COVID-19 disease (most of whom were on stable ART), age and diabetes were frequent confounding factors and probably the main drivers of the severe illness. In some instances, lacking recent viral load or CD4 counts and facing SARS-CoV-2 testing delays, we empirically treated both COVID-19 disease and Pneumocystis jiroveci pneumonia. The key clinical features of these conditions (bilateral ground glass opacification, severe hypoxemia) made distinguishing between the two difficult. Most of the HIV-infected population in Africa is still under the age of 65, and that age advantage appears to have mitigated any immunological vulnerability.
Diabetes, obesity, and other non-communicable diseases are on the rise in East Africa, yet the rates remain well below American levels. The vast majority of patients admitted with severe COVID-19 to our ward had risk factors of age, diabetes, obesity, kidney disease, or cancer. A number presented with new-onset diabetes and diabetic ketoacidosis.
3. Kenya and many parts of Africa is largely an outdoor society. Because of the lack of extreme cold weather and the relative paucity of indoor settings, many activities occur outdoors. This may be a factor in reducing superspreading events which are mostly from indoor congregate settings.
Africa possesses relatively few sealed and air-conditioned buildings. Most of the day is spent outdoors or in well-ventilated structures with open doors and windows. When I went to work at another mission hospital farther away from the country’s COVID-19 hotspots, I rounded on narrow wards with all the windows open and a brisk cross-breeze.
Other explanations for the comparatively mild African epidemic have been put forward. Pre-existing immunity to other common cold coronaviruses, perhaps a result of crowded living conditions, may have lent some protection. What we know about waning immunity to these weaker cousins of SARS-CoV-2 suggests any such effect may not fully account for the low rates of severe disease. Even those with HIV infection on successful ART would be expected to possess weaker cell-mediated immunity. A recently released preprint found that the major genetic risk factor for severe COVID-19 disease moved from Neanderthals to Homo sapiens and is virtually absent from African populations. The OR of 1.6 for severe disease among carriers of this DNA segment, however, is less than the OR for death found for HIV, current or past tuberculosis, and diabetes in the South African study cited above.
The observed outcome has allowed those of us involved in African clinical care to breathe a grateful sigh of relief. It should also humble us, especially those (including myself) who feared a much worse course. Medical and epidemiological knowledge is often provisional. Given past experience, we can be forgiven the preparations taken. Procurement of personal protective equipment both reduced risk for health workers and raised morale. Our organization and others are moving forward with plans to make oxygen more accessible; the pandemic appears to have stimulated interest in such system-wide improvements. At the hospital where I worked on the COVID-19 ward, years of investment in training intensive care nurses and clinicians saved lives. Graduates of the hospital’s ICU training programs are fanning out across the country as policymakers recognize the need for a higher standard of care to confront a range of health problems.
With the waning of the epidemic, patients have begun to return to hospitals. Reports of disrupted access to routine care — HIV, tuberculosis, vaccinations, and surgery — portend a setback for recent advances in African health metrics. Suspicion for active COVID-19 disease hinders normal hospital operations, resulting in canceled surgeries and delayed chemotherapy. The lack of widespread and rapid testing compounds these delays. COVID-19 will confuse the differential diagnosis for months or longer, creating clinical uncertainty and complicating staffing of limited isolation space.
These reflections cannot be the final word. A second wave (or perhaps just a ripple) may yet wash over Africa. Travelers may seed a new outbreak. Immunity may wane. The CEO of India’s Serum Institute has warned that adequate vaccine supplies for worldwide coverage may not be available until the end of 2024. Cases and clusters will likely sporadically occur for a prolonged period.
But at least for the time being, thankfully, Africa appears to have dodged a bullet. Benevolent epidemiology has triumphed over sophisticated medical capacity.
Jon Fielder, MD, is chief executive of African Mission Healthcare, a U.S. and Kenyan non-profit organization that strengthens mission hospitals to aid those in greatest need. He lives in Kenya and serves as consultant physician at Maua and Kijabe hospitals. If interested in learning more about AMH, contact Fielder at [email protected]
Last Updated October 21, 2020
Source: MedicalNewsToday.com
