I read that 9 out of 10 kids gain immunity from the first shot and the second is done to catch the other 10 (well 9 out of 10 again). I got my son an appointment for his second one. But I know he spiked a high enough for me to call the doc fever 10 days after his first MMR. For me, that means it was prob 103. She says that was a common side effect about 10 days later and lasted a couple days. My kids aren't pukers thank goodness and knock on wood. But... The appt is Tuesday. 10 days from that is the day before we leave. I am now feeling like I have a much higher chance of him spiking a high fever from the shot than catching measles after having one MMR. And my daughter can't get her second one yet anyway. But... Its the measles! Is it1954? Why am I worried about measles? Because people suck. Anyway, not sure what I'm gonna do... We are going for sure... But can't decide what to do about my son!