Ironically back in the day, Mumps was a rite of passage. Once you had it, you were immune for life.
Unfortunately this is not the case for some vaccines.  The problem especially with the multiple
vaccines like the MMR vaccine are the adjuvants they contain such as MSG, Aluminum, methyl mercury
(thimerosal) and other substances which may damage your immune system.  The problem this presents
is  a serious threat to one's health specifically to infants and young children who on average now
receive 20 vaccines by the age of six as their immune system is not fully developed and to the sick and elderly whose immune system may have been compromised yet  are encouraged to take the flu
vaccines  and other vaccines.  This is great for the medicos and big Pharma to the tune of
billions each year.  Everyone should weigh very carefully the pros and cons related to these vaccines.