Once vaccinated it takes several WEEKS to sero convert and get immunity.So you can STILL catch it if you were recently vaccinated. As for the safety of the vaccine , the number of reactions and adverse effects are NO WORSE than the seasonal flu vaccine. Both drugs are made the EXACT SAME WAY. I think the media with all its crap about the Swine vaccine from years ago has made people ridiculously on edge about it.I vaccinated my whole family including my kids,nieces,nephews and everyone has been FINE.If you react to seasonal flu vaccine , you will react to H1n1. Also take into account that they have had record turnout for people to receive all flu vaccines this year....INCLUDING PEOPLE WHO NEVER HAD IT BEFORE AND DIDN'T KNOW THEY WOULD REACT.