Then came the coronavirus pandemic.
43 of the 54 states in Africa closed their borders as a result.
The African Union warns that border closures for people and goods could have a "devastating effect on the health, economy and social stability of many African states" that rely on trade with neighbors.
The GAVI vaccine alliance warned that vaccines are running out in some African countries due to border closures and restricted air traffic. Although GAVI says the problem has now been resolved, the example shows how much health care on the continent also depends on flexible borders.
Africa is heavily dependent on the mobility of its workforce. But right now, that workforce is stuck in place.