BOSTON -- Fifteen Needham firefighters and several Needham residents were caught in a medical mix-up when the H1N1 vaccine they thought they were getting turned out to be a vaccine for another strain of flu.

NewsCenter 5's Randy Price reported Monday that the Centers for Disease Control and Prevention is now warning health departments about the possible vaccination label confusion.

The label of the seasonal flu vaccination had H1N1 on the label as one of the strains targeted -- but not the current H1N1 strain.

Paul Buckley, the Needham Fire Department chief, was among those coming in Monday to get the H1N1 vaccine.

Buckley had been notified by the department that the vaccination he originally got, along with a number of his colleagues, was the seasonal flu vaccination by mistake.

In all, 47 people were affected. The mistake left people confused and concerned.

"Hopefully, we haven't had any issues in the past week where some of the people came in contact with the H1N1 virus or possibly got sick from it believing they were vaccinated when they actually weren't," Buckley said.

The town's health department has been calling everyone to tell them about the mistake. Officials said it was harmless and amounted to getting a booster for the seasonal flu.

Dr. Janice Berns said it is the first mistake like this that she has seen in her 40-year career in public health.

"I think the label doesn't appear to be clear," she said.

Health departments are now being alerted to the possibility of making this mistake.