My mother used to take us to measles, mumps and chicken pox parties so we could be exposed and get it over with
I wouldn't trust that immunization method with the current variants of measles.
Measles is far more dangerous than most people realize. A serious complication is acute encephalitis, or inflammation of the brain, which can result in permanent brain damage in one of every 1,000 cases. In the U.S., death from neurologic or respiratory complications of measles occurs in one to three of every 1,000 cases.
School-age children are recommended to receive yearly injections of common vaccines that include those for chickenpox, mumps, measles, rubella, tetanus, and influenza. In our school district, children are required to have medical documentation of immunization in order to attend class. I think that is wise because our region is a major port of entry.
The purpose of the vaccines is to provide herd immunity. For information about herd immunity, consult the many You Tube videos on the subject.