ONEs Africa emerges from its second wave of Covid-19, one thing is certain: having officially registered more than 3.8 million cases and more than 100,000 deaths, it has not been spared. But the death toll is still less than experts predicted when the first cases were reported in Egypt, just over a year ago. The relative youth of African populations compared to those in the global north – although it is an important contributing factor – may not fully explain the discrepancy. So, what is really happening in Africa, and what does the Covid-19 experience on that continent teach us about the disease and about ourselves?
“If someone had told me a year ago that we would have 100,000 deaths from a new infection by now, I would not have believed it,” says John Nkengasong, a Cameroonian virologist who heads the African Centers for Disease Control and Prevention (CDC) in Addis Ababa, Ethiopia. In fact, he deplores the shocking normalization of death that this pandemic has generated: “One hundred thousand deaths is a lot of death,” he says.
It is also an underestimate. Underreporting is happening around the world, but the fragility of many African health systems and the relative inaccessibility of testing – of which more than 35 million have been carried out since the pandemic began, in a population of 1.2 billion – are exacerbating the problem there. A study to be published soon in the British Medical Journal, which involved the post-mortem PCR test of 364 bodies in a morgue at a university hospital in Zambia’s capital, Lusaka, showed that one in five was infected with the virus. Most died before arriving at the hospital, without being tested.
Christine Jamet, director of operations for the Geneva-based charity organization Médecins Sans Frontières (MSF), says it will take time to establish the full impact of African epidemics, but the idea that the continent has had slight contact with Covid -19 it’s wrong. Many African countries implemented measures at the same time as Europe last spring, before reporting any case – and, as a result, flattened the initial curve much more effectively – but were hit hard by the second wave. In today’s hotspots, which include Eswatini, Malawi and Mozambique, “hospitals are overcrowded,” says Jamet. “We put tents next to them to care for patients who otherwise would not have beds.” The situation was made worse by a lack of oxygen – one reason, says Nkengasong, why the average lethality rate (CFR) across Africa recently exceeded the global average of 2.2%. It is now at 2.6%.
The CFR is in itself a blunt instrument, since a “case” is more difficult to define – and with regard to the management of the pandemic, less informative – than an infection, whether it produces symptoms or not. But the test is not good enough across Africa for the most useful infection mortality rate to be calculated. And yet, even counting the underreporting, Nkengasong believes that death is visible enough in African communities that he can confidently say that, in general, the disease was less lethal there than in other regions. Together with his scientific colleagues from the African Task Force for New Coronaviruses (Afcor), he agrees that this paradox can be explained mainly by young people in African populations – the average age is 18 – and by the relatively low prevalence of comorbidities, including obesity and diabetes, especially among the poorest.
It is difficult to discern the cause and effect in confusing epidemiological data, especially when these data are scarce, but there is now substantial evidence to support the idea that the most powerful predictors of Covid-19 mortality are age and comorbidities – something that African experts say of their local experiences confirm. Immunologist Hechmi Louzir, who heads the Pasteur Institute in Tunis, says that Tunisia – which was widely praised for dealing with the first wave but was less successful the second time – accounts for less than 1% of Africa’s population, but 6 % of their Covid-19 cases reported to date. With an average age of 33, Tunisia has one of the oldest populations in Africa.
Meanwhile, in South Africa, the main government advisor for the pandemic, epidemiologist Salim Abdool Karim, points to surveys conducted by the National Institute of Communicable Diseases that indicate that white people are dying at higher rates than blacks – the opposite of situation in the UK and the USA. The white population of South Africa is older than the black, on average. But within a certain age group, says Karim, blacks are slightly more likely to die than whites – an effect that is probably due to the fact that blacks come later for treatment. This, in turn, is probably related to access to health care, as white South Africans are more likely to pay for private care. Although the quality of care is practically the same in the public and private systems, says Karim, it can be more difficult to be seen in a public clinic. The increased risk of overcrowding can also act as a deterrent. (There may also be a trade-off in the operation, Jamet says, with richer, older white people making up for their greater vulnerability to Covid-19, to some extent, seeking treatment earlier.)
Many other theories have been proposed for what the researchers called “the African paradox. The most controversial is probably that poverty protects: the idea that people living in populous environments, such as neighborhoods, where social distance is more difficult to reach, may have been more exposed to coronaviruses related to what causes Covid-19 – including four that cause the common cold – and acquired some immunity to Covid-19 as a result. There is some evidence for this cross-protection, but the theory has not stood the test of time. “If these four coronaviruses protected you, we would see that in the slums of Mumbai and in the slums of Brazil, but we don’t,” says Karim. Infection with original variants of the Covid-19 virus does not necessarily even protect against the new variant first described in South Africa, he says.
Linda Benskin, a wound care nurse from Texas, argued that high levels of vitamin D – which is produced mainly in the skin when exposed to UVB radiation in sunlight – protect Africans against Covid-19 and therefore more More than 200 scientists and doctors signed an open letter in December, urging governments to act to increase levels of vitamin D in other populations. The World Health Organization (WHO) remains unconvinced, however, and has made suggestions that vitamin D supplements effectively treat Covid-19 (it does not mention prevention) on its “Mythbusters” page. There, the idea comes up against theories that hot and humid climates and antimalarial drugs related to hydroxychloroquine are protective – both without foundation, according to the WHO.
Then there is the category of theory for which the jury is still determined – that the genetic background of Africans may be playing a role, for example, by influencing the prevalence of the ACE-2 receptor that the virus uses to invade human cells, or The African immune system has been prepared to fight the virus, either by other types of vaccines or by high levels of parasitic worms infection.
While again difficult to demonstrate, most experts seem to be willing to agree that experience with other serious infectious diseases, including Ebola – of which there are active outbreaks in the Democratic Republic of Congo and Guinea – has prepared African populations for deal with Covid-19. “The government was able to quickly build a consensus on measures that were, a priori, drastic and unpopular,” says Amadou Sall, who runs the Pasteur Institute in Dakar, Senegal, on that country’s rapid response to the first wave. “Tracking contacts in countries like [the UK] it’s a theory, ”says Nkengasong. “In our countries it is a reality.” Jamet highlights the flip side of this: MSF skills are in high demand across Europe, she says, where “experience in epidemic management has been completely lost”.
For the time being, then, the African paradox persists. “We don’t have an explanation as to why the impact was less,” says Karim. “I have an unanswered question.” Nkengasong says that the answers can take years and, until then, most theories remain on the table. An initial prediction has been refuted, however: that many Africans whose immune systems have been weakened by HIV / AIDS infection would die from Covid-19. Fortunately, that didn’t happen, says Karim, for a reason that, in retrospect, seems obvious. The two diseases do not affect the same age groups, as HIV is mainly a disease of young people in Africa. There is, however, some evidence that when HIV-infected people get Covid-19, their Covid-19 may be more serious.
Ghana received the first African shipment of the Covova-19 vaccine from the Covax initiative this week – 600,000 doses of the Oxford / AstraZeneca vaccine. Vaccine programs are underway on the continent, amid confusion caused by the lack of data on the prevalence of new variants in many countries (from the available data, it appears that the variant described for the first time in the United Kingdom is spreading in Africa West, while the first one described in South Africa is spreading to the north from there), and a lack of data on how the various vaccines work against these variants. Africa’s CDC is trying to solve the first problem by stepping up sequencing efforts – it plans to sequence 50,000 viral genomes by December, up from about 7,000 now – and the second gathering data on hospitalizations and deaths as the distribution of vaccines continues.
Nkengasong’s goal is that 35% of Africans, mainly urban, will be vaccinated by the end of this year, and 60% by the end of 2022. Thus, he says, it should be possible to reduce the continental epidemic to localized outbreaks, which they can be eliminated by public health campaigns – with the ultimate goal of ridding Africa of Covid-19 in five years.
When he first proposed the 60% target, he says, it was informed by some beyond Africa that 20% was more realistic – the proportion of each population considered vulnerable to Covid-19. “But if you only vaccinate 20%, it will remain a continent of Covid forever,” he says. This is because in Africa the disease is transmitted by young people, who are not considered vulnerable and tend to have mild symptoms or no symptoms at all, but generally live in multigenerational families.
Paradox or not, says Nkengasong, Africa cannot afford Covid-19. And speed is essential when it comes to vaccination, because if it doesn’t happen quickly, the immune escape will make vaccines more and more ineffective and elimination will be beyond the reach of the continent. That is the main reason why he and his colleagues at Afcor condemn vaccine nationalism – both inside and outside Africa. The other reason is that, in this hyperconnected world, Africa-with-Covid is bad for everyone. As Karim likes to repeat: “Nobody is safe until everyone is safe”.