PRETORIA, SOUTH AFRICA—Addressing supporters Monday from the hospital bed where he is being treated for a recurring lung infection, former South African president Nelson Mandela admitted that the millions of thoughts, prayers, and well-wishes he has received have played absolutely no role in his improving health, and that his recovery has been 100 percent dependent on doctors. “In these past days of struggle, I have seen messages of hope and love from citizens around the world, which, while nice, weren’t going to help remove the excess fluid from my lungs. Doctors do that,” Mandela told reporters. “The capacity of gentle souls to unite their voices in a message of peace and strength is certainly the greatest gift of mankind—I’m not denying any of that. But when you’re a 94-year-old man with a horrible lung infection, you need trained medical professionals. That’s really most important. All that prayer stuff is, frankly, pretty useless.” Mandela said that while his doctors were compassionate and thoughtful human beings of unflinching character, that’s not going to do anyone any good if they “don’t give me some codeine.”