Sure. When only every other children die before the age of 2 instead of 80%, that is a huge improvement, although I wouldn't want to live in those conditions...
Sub-Saharan Africa was one of the last regions to advance out of the Stone Age. Some populations were Neolithic (agriculture), others were Paleolithic (nomadic hunter-gatherers) when Europeans and Arabs began colonizing, along with some influence from Iron Age North Africa.
To my knowledge it was the largest, densest Stone Age population at that time. Australia, Siberia and the Western Hemisphere north of the Rio Grande had very low population densities. At that time, with no vaccines and antibiotics, 80% infant mortality (before adulthood, which was about 13-14 in those days) was the norm everywhere and it was higher in dense populations. Even in 17th-century London 80% of babies may have died before age 2--I haven't looked that up but I'm sure they died before age 10.
So the fact that the infant morality rate was at that level doesn't mean that the continent had slid backwards, merely that it had not advanced.
Westerners tried to "save Africa," but without understanding the consequences of their efforts. They brought modern medicine and vaccines to the region, attempting to leapfrog the cultures from the Paleolithic to the Industrial Era in one generation--skipping (for many) the Agricultural Revolution, the rise of civilization, the Bronze Age and the Iron Age; each of these Paradigm Shifts had taken centuries or millennia for the rest of the world to adapt to.
Stone Age people have large numbers of children: they have to so enough survive to keep the community from disappearing through attrition. But of course they don't understand this "reasoning," it's an instinct--look at how long it's taken the industrial world to learn to stop breeding itself into oblivion. So when their children began to survive into adolescence and even adulthood, they had no reason to suspect that they should stop having so many; it seemed like a blessing.
Of course this blessing overwhelmed their economy, particularly their ability to grow food with pre-industrial technology. The colonial powers had divided the continent into arbitrary "countries" made up of fragments of rival tribes, so it was nearly impossible to establish a sense of community to solve these problems together.
So instead of dying from malaria and dysentery, they starve to death. And of course the AIDS epidemic came along, courtesy of the colonial powers who established trade routes that cris-crossed the continent and allowed everyone to infect everyone else with whatever disease was going around. (The origin of the epidemic has been pinpointed to the Congo, a veritable Union Station of trade routes from which it even spread to other continents.)
So the fact that the poverty rate in Africa has fallen below 50% probably means that conditions there are better than they have been in centuries.
The same is true for the world at large. In this century, the number of people worldwide living in poverty has fallen below one billion. Obviously you can thank post-Mao economics in China for much of that. The new hybridization of communism with a little capitalism and a lot of Confucianism has catapulted them into relative prosperity. India is doing alright. Mexico, in one generation, has transformed itself into a middle-class country. Brazil now has the world's six-largest economy and the failing states of Europe are looking to
them for help!
