NAPA, CA – OCTOBER 02: A man receives a flu shot as he sits in his car during a drive-thru flu shot clinic October 2, 2009 in Napa, California. The County of Napa Public Health Department held the one of eight scheduled drive-thru flu shot clinics where seasonal flu shots will be given for free to anyone who attends in an effort to vaccinate as many people in Napa County as possible before the start of the flu season. (Photo by Justin Sullivan/Getty Images)