Since it goes against the general constitution of the vaccine movement to admit a vaccinated child has a certain disease that he has been vaccinated for, it is interesting when these articles pop up. They do pop up quite a bit though, so it makes one wonder how many of these cases really occur.
If this child had been unvaxed (which usually means they conveniently can't find out vax status or has had most shots but not all), that poor family would be a part of a witch hunt and we'd hear all the usual about how non-vaxing parents hate their children and are destroying the planet.
Only the vaccine movement can use the slogan "We admit our product does not work, but that just means we need to give you more of it."