In light of recent measles outbreaks in the US, would you recommend an MMR booster for an immunocompetent patients born before 1957?   

I would not recommend a measles vaccine for a person born before 1957. This year has been chosen because people before born before 1957 have a very very high likelihood of having had measles because virtually all children got this highly contagious disease. On the other hand, there is no harm to get...

I think titers are useful. Would revaccinate if not at protective levels.

Currently, I would not recommend a booster for all immunocompetent individuals born before 1957. However, for healthcare workers, it's recommended that they have proof of immunity. If they do not have this already, I would check titers and revaccinate if not immune. 

More of a question - What about those born between 1963-1968, have not received a booster, and are not sure if they received the attenuated or inactivated measles vaccine?  It is my understanding that the inactivated measles vaccine was still available during this period and was not very effe...