The Center for American Progress reports
A federal judge has ruled in favor of a New York City policy that allows schools to ban unvaccinated kids from attending classes when another child has come down with a vaccine preventable illness, the New York Times reports(paywalled).
[...]
Nicole Phillips, the mother of two[...], explained when she sued back in 2012. "We'd rather rely on our natural immune system and our faith in God. This is about my children's rights."
Judge William F. Kuntz II of the Federal District Court in Brooklyn disagreed with that argument, determining that the Supreme Court has "strongly suggested that religious objectors are not constitutionally exempt from vaccinations" and concluding that the city's strict vaccine guidelines are in place to safeguard its residents' well being.
[...]
the judge cited a 1905 Supreme Court ruling upholding a fine for a Massachusetts man who refused to get vaccinated during a smallpox outbreak
(Score: 1) by sjwt on Tuesday June 24 2014, @01:43PM
The immunity provided by a vaccine is not 100%,it lies between 90-99.99999% good enough for general causal exposure.
your own immune system could be weakened from fighting another issue at the time or by just being generally compromised to begin with, the virus could have evolved to get around the immunity or you could be living in a cluster where a lot of ppl are not immunized, and as such your body could be overwhelmed by others around you giving you a massive espouse that you can not hope to fight.