no vaccine is 100% effective. unfortunately it is possible for someone who is immunized to still get measles. your child is as protected as any child who is immunized so exposure is really unknown. parks like disneyland have tens of thousands of adults and children touching everything and breathing on each other. many park goers are not immunized and do not practice good hygiene so you take that chance. you also take a similar chance sending him to day-care taking him to the mall etc. disneyland is clean but the people who go there may not be as clean or disease-free. this recent outbreak is distressing since measles is preventable if everyone does their part by being adequately vaccinated. the more people who are vaccinated the less chance of any of these outbreaks. as a parent only you can make this decision. since he is only three you will have ample time in the future to go when this outbreak is controlled or over. if you decide to go statistically he will most likely be fine but remember there is no 100% certainty.
is it safe for my 3 year old to go to disneyland in light of the recent measles outbreak? . she has only received one mmr vaccine at 12 months of age and isn't due for the second dose until next year.