San Luis Obispo County Health officials say the number of people getting the flu is on the rise throughout the county and the nation. While flu season starts in October or November it can last as late as May. So, officials say it’s not too late to get your flu shot. According to the advisory, those most at risk for influenza include adults over the age of 65 and young children under the age of 5. Children 2 years of age and younger are especially vulnerable. They add that even young, healthy people can experience serious complications from the flu.