School is officially back in session and thousands of students on Valley playgrounds are some of the most at-risk of catching and spreading the flu. Once kids start getting the flu it is very communicable.
Fresno Unified School's Health Director Diane Torna is reminding parents to keep sick children, at home.
Torna explained, "So they don't expose it to other students."
Health experts say the virus is hitting the U.S. unusually early and hard this year and California hasn't seen the worst of the outbreak.
Dr. Richard Besser said, "One of the reasons they think it may be a more severe season is that one of the strains that is circulating has been known in the past to cause more severe flu."
ABC Chief Health and Medical Editor Dr. Richard Besser is encouraging anyone older than six months and in good health to get a flu shot. But check in first with your doctor, if you have a serious illness. He said, "If you are a child or an adult who has an immune disorder, you're being treated for cancer then flu vaccine is not recommended for you."
Dr. Besser say there's no need to head into the e-r if you're handling the virus okay. He explained, "If you were healthy before you got the flu and you are handling it well, you are drinking fluids and you are managing your fever. You are feeling lousy but you are able to function the last place you want to be is sitting around the emergency room, you can pick up other things there."