With air mattresses and beach chairs tucked under their arms, they began arriving as early as midnight, lining up down the sidewalk and around the corner in downtown Sao Paulo, Brazil. “Make sure you have your vaccination card and your number in hand,” a public health clinic worker shouted to those lucky enough to have one of the 300 numbers that would allow them to receive a full dose of the yellow fever vaccine, good for a lifetime. “If you’re not here when your number is called, you’ll lose your place in line!”Brazil is fighting to stay ahead of one of its worst epidemics of yellow fever, a

sometimes-fatal virus transmitted by Haemagogus and Sabethes mosquitoes and named for the yellowing of the skin and eyes of those infected. Though the surge has largely been in rural areas, there is increasing concern that if people don’t get the vaccine, the virus could spread into the country’s biggest cities. Those lined up on the January morning in Sao Paulo were also racing against the clock. The Brazilian government, faced with the task of vaccinating millions as quickly as possible, READ MORE