Can 'friendship paradox' help scientists track flu?

Are you the last one to get the flu?

It may just be because you're no Kevin Bacon.

According to a new study, which appears in the journal PLoS ONE, popular people come down with the flu about two weeks earlier than a randomly selected group of people.

The study was based on a concept known as the "friendship paradox," when people are asked to name their friends, their friends tend to have more social contacts than they do.

The researchers chose 319 Harvard undergraduates at random and asked them to name their friends, which resulted in a list of 425 students who were named once or more.

About a third of the students reported catching the flu in the fall and winter of 2009, and those in the "friends" group were diagnosed 14 days earlier, on average, than those in the randomly chosen group. And, the epidemic peaked among the friends group a full 46 days before it peaked in the general population of students.

Some see the findings as a promising way to track and fight epidemics, especially in self-contained settings such as college campuses and military bases.

"Checking for disease among the 'Kevin Bacons' is an appealing concept," said Philip Polgreen, M.D. and assistant professor of medicine and epidemiology at the University of Iowa. He was referring to the actor who is central to a game connecting him with other stars through fewer than six degrees of separation.

Others aren't so sure, saying it's easier and cheaper just to keep track of the number of flu patients who show up at hospitals and clinics.

Popular or not, we're all going to be facing the flu season soon, and local clinics are receiving this year's vaccine. Check with your health care provider to see if a flu shot is right for you.

There's a better chance of that this year.

The Centers for Disease Control and Prevention has begun recommending that everyone over six months old get vaccinated. Previously, the CDC focused on vaccination of higher risk groups, children six months through 18 years of age, and close contacts of higher risk persons.

Also new this year, you will only need one shot to protect against both the seasonal flu and H1N1.

Sure, you may be no Kevin Bacon, but you still need to wash your hands, cover your mouth when you cough, stay home if you're sick, and call about getting a flu shot.