SUNDAY, March 16, 2014 (HealthDay News) -- Think you know who has the flu? Think again: a new study finds that three-quarters of people infected with seasonal flu and swine flu in recent years showed no symptoms.
Researchers analyzed data gathered in England during the winter flu seasons between 2006 and 2011, including the 2009 H1N1 "swine flu" pandemic.
Overall, about 18 percent of unvaccinated people became infected with an influenza virus, but only 23 percent of them went on to develop flu symptoms, the researchers reported March 16 in The Lancet Respiratory Medicine.
What's more, only about 17 percent of infected people became ill enough to see a doctor, the British study found. And compared with some of the seasonal flu strains, the 2009 swine flu strain actually caused much milder symptoms.
The findings suggest that relying on data about flu-related visits to primary care doctors underestimates the extent of flu infections and illnesses, the researchers said.
Overall, the infection rate for the winter flu seasons as calculated in the study were an average of 22 times higher than the rates recorded by standard methods.
...
Researchers analyzed data gathered in England during the winter flu seasons between 2006 and 2011, including the 2009 H1N1 "swine flu" pandemic.
Overall, about 18 percent of unvaccinated people became infected with an influenza virus, but only 23 percent of them went on to develop flu symptoms, the researchers reported March 16 in The Lancet Respiratory Medicine.
What's more, only about 17 percent of infected people became ill enough to see a doctor, the British study found. And compared with some of the seasonal flu strains, the 2009 swine flu strain actually caused much milder symptoms.
The findings suggest that relying on data about flu-related visits to primary care doctors underestimates the extent of flu infections and illnesses, the researchers said.
Overall, the infection rate for the winter flu seasons as calculated in the study were an average of 22 times higher than the rates recorded by standard methods.
...
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