Went to Disneyland over the Christmas break, got back and came to a family party. Turns out they had contracted measles at Disneyland, but weren't showing symptoms yet at the family party. By youngest had only had one of the required 2 MMR shots because he wasn't old enough for the second yet. Another cousin's child was an infant, so none of the MMR shots yet. Both had to be quarantined for 3 weeks. Thanksfully, nobody else got the measles, but we were very lucky.