Vaccines are the first line of defense against highly infectious diseases. Just how you don't prepare for a marathon as soon as the race starts, you prepare weeks, months, or even years in advance. The same idea can be applied to vaccinations. Vaccines can take several months to create the appropriate antibodies within the body. if we can prevent enough of the population from getting illness, it can be also a boost for the economy. Think of the Spanish flu back in the early 1900's. It decimated populations and caused productivity to be reduced.
No one should have the capacity to spread dangerous diseases that we already have a decent vaccine against. Personal freedoms only go so far as allowing individuals to decide what is right for them, not what is right for everyone else. A person who doesn't get the measles vaccine presents as a medical concern to everyone who isn't vaccinated around them, and as many people cannot get vaccinated (i.E. The elderly, infants, the immunocompromised), they are putting others at undue risk for acquiring these diseases.