BERLIN—German vaccine maker BioNTech, which developed the first widely approved shot against COVID-19 together with Pfizer, unveiled plans Wednesday to establish manufacturing facilities in Africa that would boost the availability of much-needed medicines on the continent. The modular design presented at a ceremony in Marburg, Germany, consists of shipping containers fitted with the equipment necessary to make the company’s mRNA-based vaccine, save for the final step of putting doses into bottles, a process known as fill and finish. “Our goal is to enable mRNA production on all continents,” BioNTech CEO Ugur Sahin told The Associated Press. BioNTech has been criticized by some campaign groups for refusing to suspend its vaccine patents and let rivals manufacture the shots as part of an effort to make them more widely available, especially in poor countries. The company argues that the process of making mRNA vaccines is difficult and it prefers to work with …