Shots - Health News Fri March 8, 2013 Flu Risk And Weather: It's
Not The Heat, It's The Humidity As winter wanes into spring, flu
season wanes, too. But while people get the flu when it's cold
in the United States, in Senegal they're getting sick when it's
hot. It's a puzzle that's baffled scientists for decades. Now,
they think they might be have an explanation, though it's not a
straightforward one. Places where humidity and temperature drop
seasonally, like North America in the winter, have flu outbreaks
then. But in the tropics, where the air stays hot all year long,
flu season tends to peak with the heavy monsoon rains. Over the
years, scientists have come up with lots of theories as to why
influenza outbreaks are so strongly tied to the calendar. Maybe
it's because people are inside more in cold weather, one theory
holds, so the virus spreads more easily. Or maybe it's because
people aren't out in the sun making Vitamin D, and their immune
systems are weak. Or maybe it's because people travel for holida