Flu Research

Last week, National Geographic wrote an article on why the flu is prevalent in the winter and what allows its transmission. In the article, they heralded a study that is going to be published in Proceedings of the National Academy of Sciences. Here is some of the article:

"Absolute humidity conditions explain most of these changes," Shaman said. The researchers do not know exactly what it is about low absolute humidity that the flu virus likes. But they suggest that absolute humidity levels be raised in buildings such as hospitals and medical clinics where the disease most often spreads.
"This gets us a big step closer to one type of mechanism" for how the flu spreads, said epidemiologist Marc Lipsitch of Harvard University. "One really key
question is how much influenza is transmitted in tropical locations"—places with
high absolute humidity year-round—"and how this compares to temperate parts of
the world,"

While this may be news to some, these research findings are not unique, nor are they recent. I'm surprised the journal selected the study for publishing because these findings and additional insights have already been answered - or at least discovered.

Peter Palese, a flu researcher who is professor and chairman of the microbiology department at Mount Sinai School of Medicine in New York published a study a year and a half ago linking flu transmission rates with temperature and humidity. Here is an article talking about his findings, as well answering some of the questions raised in the "newer" study:

Air temperature and humidity in the guinea pigs' quarters were varied, and they discovered that when the air temperature was at 41 degrees the virus was transmitted. As the temperature rose there was a significant decrease in the transmission of the virus and at 86 degrees, the virus was not transmitted at all.
A[sic] low humidity of 20 percent, the virus was transmitted and when the humidity reached 80 percent the virus was not transmitted at all. Dr. Palese said that this
flu virus spreads through the air, unlike the cold virus, which spreads by direct contact when people touch surfaces that had been touched by someone with a cold or a handshake with someone who is infected. Cold air makes a stable
environment for the flu virus. Low humidity also helps the virus particles remain in the air. The viruses float in the air in little respiratory droplets. With the humidity in the air, those droplets pick up water, grow larger and fall to the ground.

I guess the lesson to be learned is get a humidifier or live in a more tropic climate if you want to avoid the flu.