There shouldn't be a law requiring it at all. But there is. EO's suck. Of course, some people love 'em, depending on the topic at hand. If one truly believes the vaccine is dangerous, then the process shouldn't be much of a hindrance.
Perry's EO is illegal, and and illegal act has no force in law.
Why should I have to go through ANY 'process' because he wants to play King of Texas?