https://apnews.com/fc4c536d62c5ef25152884adb1c14168 > GAMPELA, Burkina Faso (AP) — The chain breaks here, in a tiny medical clinic in Burkina Faso that went nearly a year without a working refrigerator. > From factory to syringe, the world’s most promising coronavirus vaccine candidates need non-stop sterile refrigeration to stay potent and safe. But despite enormous strides in equipping developing countries to maintain the vaccine “cold chain,” nearly 3 billion of the world’s 7.8 billion people live where temperature-controlled storage is insufficient for an immunization campaign to bring COVID-19 under control.