Marina Pollán of the Carlos III Health Institute in Madrid, who led Spain’s antibody survey, says Africa’s youthfulness may protect it. Spain’s median age is 45; in Kenya and Malawi, it’s 20 and 18, respectively. Young people around the world are far less likely to get severely ill or die from the virus. And the population in Kenya’s cities, where the pandemic first took hold, skews even younger than the country as a whole, says Thumbi Mwangi, an epidemiologist at the University of Nairobi. The number of severe and fatal cases “may go higher when the disease has moved to the rural areas where we have populations with advanced age,” he says.
Jambo is exploring the hypothesis that Africans have had more exposure to other coronaviruses that cause little more than colds in humans, which may provide some defense against COVID-19. Another possibility is that regular exposure to malaria or other infectious diseases could prime the immune system to fight new pathogens, including SARS-CoV-2
