Africa facing a quarter of a billion coronavirus cases, WHO predicts
But continent will have fewer deaths than Europe and US because of its younger population and other lifestyle factors
Men in Mali greet each other without touching hands to prevent the spread of Covid-19, 29 March, Bamako. Photograph: Michele Cattani/AFP via Getty Images
Nearly a quarter of a billion people across 47 African countries will
catch coronavirus over the next year, but the result will be fewer
severe cases and deaths than in the US and Europe, new research
predicts.
A model by the World Health Organization’s (WHO) regional office for Africa, published in the BMJ Global Health,
predicts a lower rate of transmission and viral spread across the
continent than elsewhere, resulting in up to 190,000 deaths. But the
authors warn the associated rise in hospital admissions, care needs and
“huge impact” on services such as immunisation and maternity, will
overwhelm already stretched health services.
About one in four (22%) of the one billion people in the countries
measured would be infected in the first year of the pandemic, the model
suggests. However the disease is likely to linger for longer – possibly
for several years.
The continent’s much younger age profile compared to other countries is
behind the lower transmission rates, the authors say. Lower rates of
obesity in African countries, compared to the US and elsewhere, also
help to slow its progress.
“The biggest factor that plays out in our numbers is age,” said data
analyst Humphrey Karamagi. “We also have very few people who are obese,
although the numbers are rising. But not at the levels in the US.”
A report by the UN Economic Commission for Africa in
mid-April predicted a much higher infection and death rate on the
continent, of 1.2 billion infections and 3.3 million deaths. However,
the models are not comparable, because the new model uses data from the
WHO African Region, a smaller grouping of the continent that does not
include Djibouti, Egypt, Libya, Morocco, Somalia, Sudan or Tunisia. The
paper has been peer-reviewed. Scientists have also learned much more
about the virus and its transmission since the UN research.
“We tried to factor in what we are seeing on the ground,” said Karamagi.
“And we are seeing slower transmission rates in African countries
compared to Europe and the US.”
Some commentators have speculated that African countries may be
reporting fewer cases because they are not detecting them, but Karamagi
points to South Africa, which has “good detection capabilities, but low
numbers”.
“There might be an effect of reporting but we do not think that fully
explains the rates, when we are seeing the pattern we are seeing. There
is something around social-cultural or developmental or environmental
structure that is slowing the transmission rates,” he added.
The researchers have calculated the risk of exposure, and estimated the
number of infections and deaths for each of the 47 countries in the WHO
region.
“We are including a risk of exposure into our estimation of the risk of transmission” said Karamagi.
The risk of exposure, which is country specific, is driven by factors
including number of people in a household, population density, what
proportion of the population lives in slums, and road infrastructure.
Small countries, including Mauritius, are likely to be the most
vulnerable, while sparsely populated countries, such as Niger,
Mauritania and Chad, less so, the research found. Per head of
population, Mauritius, Seychelles and Equatorial Guinea are likely to
have the highest numbers of cases.
Larger countries, including Cameroon, South Africa and Algeria, would be
most at risk, while Nigeria is set to have the largest number of
infections overall, followed by Algeria and South Africa.
Recent data about who is likely to suffer more severe symptoms, for
instance those who are obese, or who have hypertension or diabetes, has
informed the research. Levels of diabetes in Africa are similar to
elsewhere, but the condition is more likely to be undiagnosed, so more
cases of severe infections in people thought to be healthy are expected.
“The pattern that seems to be emerging is that it is diseases of
lifestyle that pushes someone to severe illness as opposed to diseases
of poverty,” said Karamagi. “We have fewer people whose infections will
progress to a more serious disease.”
The infection mortality rate across Africa, he said, was 0.06%, compared to about 0.1% elsewhere.
