Spring Break
Humidity may stop flu virus
OSU researcher, state epidemiologist discover link between humidity and influenza
Samantha Blann
Issue date: 2/18/09 Section: News
A recent study suggests there may be another way to avoid the pathogen known as influenza.
Atmospheric scientist Jeffrey Shaman of Oregon State University and state epidemiologist Melvin Kohn with the Oregon Department of Health Services believe they have found the answer in humidity.
"How [the virus] is transmitted is not really understood," Shaman said. Scientists do, however, have a few ideas. The four ways believed to cause transmission are airborne transmission, direct physical contact with the infected, contact with an intermediate object containing the virus and contact through expelled droplets (a sneeze or a cough) from the infected.
The problem with the influenza virus is that it can survive for days after being expelled. These are the very small droplets called "droplet nuclei" which, with air currents and inanimate objects, can travel for days. Shaman and Kohn, though, believe they know how to help prevent this from happening.
A previous study examining influenza transmission among guinea pigs suggested that airborne transmission rates increase with lower levels of relative humidity. This means that the droplet nuclei are able to survive longer due to higher evaporation levels, allowing the droplet to stay afloat.
However, the actual water vapor content of air, or absolute humidity can be more beneficial to people and has been found to have more of an effect on the virus.
"I redid an analysis of their data," Shaman said. Instead of researching the effects of relative humidity on the virus, Shaman and Kohn studied the viral effects from absolute humidity.
The findings from this study suggest that influenza survival depends on the amount of water vapor in the surrounding air. In higher levels of absolute humidity, the virus cannot stay aloft as long. Further research is still needed to understand why humidity can effect the virus' survival.
Shaman and Kohn's findings also suggest an answer to the seasonal appearance of influenza. During the winter, absolute humidity levels lower, allowing the virus to increase.
"[Still], the best thing to do for the flu is to get vaccinated," Shaman said.
Student Health Services offers approximately 2,000 flu shots every flu season, along with the flu mist.
"[Approximately] 10 people a day come into Student Health Services with symptoms of the flu," said nurse Mary Bruch.
Not all of them end up having influenza, though.
"[Student Health Services] has for a number of years had an air cleaner to filter the air in the waiting room," said Dr. Phillip Histand of SHS. The hospital does not, however, have humidifiers.
Shaman mentioned that placing humidifiers in living spaces or in hospitals could actually be worthwhile, but warned that this is a trade off due to mold and other unhealthy factors that flourish under moisture.
Samantha Blann, staff writer
news@dailybarometer.com, 737-2231
Atmospheric scientist Jeffrey Shaman of Oregon State University and state epidemiologist Melvin Kohn with the Oregon Department of Health Services believe they have found the answer in humidity.
"How [the virus] is transmitted is not really understood," Shaman said. Scientists do, however, have a few ideas. The four ways believed to cause transmission are airborne transmission, direct physical contact with the infected, contact with an intermediate object containing the virus and contact through expelled droplets (a sneeze or a cough) from the infected.
The problem with the influenza virus is that it can survive for days after being expelled. These are the very small droplets called "droplet nuclei" which, with air currents and inanimate objects, can travel for days. Shaman and Kohn, though, believe they know how to help prevent this from happening.
A previous study examining influenza transmission among guinea pigs suggested that airborne transmission rates increase with lower levels of relative humidity. This means that the droplet nuclei are able to survive longer due to higher evaporation levels, allowing the droplet to stay afloat.
However, the actual water vapor content of air, or absolute humidity can be more beneficial to people and has been found to have more of an effect on the virus.
"I redid an analysis of their data," Shaman said. Instead of researching the effects of relative humidity on the virus, Shaman and Kohn studied the viral effects from absolute humidity.
The findings from this study suggest that influenza survival depends on the amount of water vapor in the surrounding air. In higher levels of absolute humidity, the virus cannot stay aloft as long. Further research is still needed to understand why humidity can effect the virus' survival.
Shaman and Kohn's findings also suggest an answer to the seasonal appearance of influenza. During the winter, absolute humidity levels lower, allowing the virus to increase.
"[Still], the best thing to do for the flu is to get vaccinated," Shaman said.
Student Health Services offers approximately 2,000 flu shots every flu season, along with the flu mist.
"[Approximately] 10 people a day come into Student Health Services with symptoms of the flu," said nurse Mary Bruch.
Not all of them end up having influenza, though.
"[Student Health Services] has for a number of years had an air cleaner to filter the air in the waiting room," said Dr. Phillip Histand of SHS. The hospital does not, however, have humidifiers.
Shaman mentioned that placing humidifiers in living spaces or in hospitals could actually be worthwhile, but warned that this is a trade off due to mold and other unhealthy factors that flourish under moisture.
Samantha Blann, staff writer
news@dailybarometer.com, 737-2231
Note: writers will not reply to comments.
Viewing Comments 1 - 1 of 1
BD3946DF-BE6E-42F2-AF66-31F107958ACF
Brian, Corvallis community
posted 2/18/09 @ 3:38 AM PST
I've heard that this was a reanalysis of data from a study that was conducted a few years before it had the benefit of the NIH information indicating general temperature as a major factor in the contagion of influenza virus. (Continued…)
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