New York City?s first responders started to get the H1N1 vaccine on Thursday.

The shots are being given out at more than a dozen locations around the city, but are not mandatory for FDNY firefighters and EMTs. As of Thursday afternoon, a little less than half of the city?s first responders decided to opt out of the vaccine.

Many of those who opted out say they are still on the fence as to the safety of the vaccine.