On march 19, 2020, 20 days after the confirmation of the first case of the Covid-19 in sub-saharan Africa, the WHO director said that Africa needed to " expect the worst ". This assertion is based on the observation that the state of the health systems of african countries would not effectively respond to the pandemic. To date, however, the african continent account for hardly 2 % of confirmed cases in the world, and less than 1 % of the deaths. Even if the limitation of the number of tests does not allow to estimate the prevalence of the disease in Africa, these statistics call into question the forecasts of alarmist and apocalyptic of an effect on a pest of the pandemic in the continent, especially in its subsaharan part.
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The Covid-19 : a pandemic linked to the age structure of populations
The data of the first countries affected, showing a case fatality of the disease concentrated in persons over the age of 60 years and a near absence of mortality among the under 20 years of age, demographers have posited the hypothesis of a differential evolution of the pandemic according to the age structure of populations. It was suggested that with a population of a median age of 18.7 years, a life expectancy at birth of 60.5 years and a proportion of people aged over 60 years of age of only 4.8 %, the pandemic has a low incidence in Africa.
However, this potential asset of his youth has been systematically demolished with the assumption that the endemic diseases affecting the continent as malnutrition, malaria, HIV and tuberculosis, by the decrease of the immunity they induce, increase necessarily the vulnerability of african youth Covid-19
While the predictions of a surge in late of the disease on the continent persist, the empirical data collected on the Covid-19 in Burkina Faso are helping to change the debate on the progression of particular disease that we observe.
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What is the relationship between age and the spread of the Covid-19 in Burkina Faso ?
Our on-going study of writing (" The effect of age on the fatality rate of Covid-19 in Burkina Faso " by Madeleine Wayack Pambè, Bruno Lankoande and Seni Kouanda) highlights the effect of age on the fatality rate of Covid-19 in Burkina Faso. The country has recorded its first case of Covid-19 march 9, 2020. At the date of may 17, it had 806 positive cases (including 508 men and 298 women) and 52 deaths. Like the rest of the sub-continent, sub-saharan, the country's population is young, with a median age estimated at 17.6 years and a life expectancy at birth 60.9 years.
in Accordance to what is observed in the western countries, the risk of hospitalization and lethality due to the Covid-19 are closely related to age in Burkina Faso. On 604 positive cases (50 deaths) analyzed in 1.8 % were less than 20 years, and no deaths had been recorded in this population.
the bulk of The deaths (66 %) occurred in people aged 60 years and over. The average age increases with the severity of the disease. She is 40 years of age among non-hospitalized patients, 50 years of age in hospitalized patients, and 64-year-old among the deceased persons. It is noted that the average age of deceased persons is much lower than that observed elsewhere – 81 years in Italy and 79 years in France, for example. It thus reflects the structure of the mortality of the country, which has few people living beyond age 64. Analyses preliminary statistics show that the effect of age on the lethality of the Covid-19 remains the determining factor, after controlling for known risk factors of the disease, including gender, and cardio-vascular diseases including hypertension, diabetes, and renal disease.
By limiting the analysis to patients admitted to hospital, for which the risk factors are available, we observe a mortality rate five times higher among individuals older than 60 years, compared to less than 40 years. The difference in lethality between the under 40 and the age group 40-59 years is modest. Diabetes and cardiovascular disease are also risk factors, but an analysis by age group indicates that their effects are more visible in the age group 40-59 years. Overall, therefore, age is the most determining factor of the lethality of the Covid-19 in Burkina Faso.
After several weeks of closure, the students were returned to school on the 11th of last may in Benin. © Yanick Folly/AFP
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The youth of its population : a strong bulwark against the Covid-19 in Africa
The first data analyzed from the Covid-19 in Burkina Faso confirm that the patterns by age of the lethality of this disease do not differ from those of western countries. Despite the lack of serological information to know the prevalence of the disease in the general population, it can be argued that with transmissibility equal to that of Europe, the african populations, in which there are few elderly people develop less symptomatic, and severe and, consequently, are less aware of death.
factors comorbidity – the presence of other diseases or pathologies, in addition to the original illness – individuals considered for the continent do not contribute either to the spread of the disease. Malaria and malnutrition (under-nutrition) affecting mainly children under 5 years of age who are not very likely to be contaminated by the Covid-19. Moreover, the evolution of the pandemic in some african countries highly affected by HIV and tb, such as South Africa seems to indicate that the progress in the treatment of patients mean that these countries are not particularly more " at risk ".
If Africa must pay a heavy toll on health in the pandemic, this will certainly be due to other indirect effects, such as the decrease in the utilization of health care and the easing of some policies in favour of the health of the mother and the child. For the moment, it is more resilient, thanks in large part to the age structure of its population made up mostly of young people.
* Madeleine Wayack-Pambè is a teacher-researcher in demography at the university Joseph Ki-Zerbo.
** Bruno Yempabou Lankoande is a researcher in demography (Institut national d'études démographiques - INED) at the university Joseph Ki-Zerbo.
*** Seni Kouanda is a professor of epidemiology at the africa Institute of public health.
