MADISON (WSAU) State health officials are urging people who haven't had a flu shot yet this year to get one now. There's been a sharp increase in flu cases over the last few weeks.

Even though flu season started late this year, it isn't too late to get vaccinated. It can take two to three weeks after getting the shot for your body to build up immunity.

It's not uncommon to see flu outbreaks in March. In some years the flu season can last into April. People can have the flu virus and unknowingly spread it. They may not have any symptoms until 3 to 5 days after being infected.