Changes

The incidence of other diseases such as [[diphtheria]], [[pertussis]], and [[measles]], has decreased greatly since the invention of vaccines against these diseases.<ref>https://www.unicef.org/pon96/hevaccin.htm</ref>

The incidence of other diseases such as [[diphtheria]], [[pertussis]], and [[measles]], has decreased greatly since the invention of vaccines against these diseases.<ref>https://www.unicef.org/pon96/hevaccin.htm</ref>

About one-third of the states have philosophical exemptions entitling parents to decline the vaccines; 48 out of 50 states have religious exemptions; all states have medical exemptions, but they are hardest to obtain.<ref>http://www.nvic.org/state-site/state-exemptions.htm</ref><ref>http://www.vaccinesafety.edu/cc-exem.htm</ref>  Some parents choose to [[homeschooling|homeschool]] rather than submit their children to numerous vaccinations as required by state laws, due to lobbying by vaccine manufacturers, as a condition of being in school.

17 US states have philosophical exemptions entitling parents to decline the vaccines; 47 states have religious exemptions; all states have medical exemptions,<ref>https://www.nvic.org/Vaccine-Laws/state-vaccine-requirements.aspx</ref><ref>http://www.vaccinesafety.edu/cc-exem.htm</ref> but they are hardest to obtain. Some parents choose to [[homeschooling|homeschool]] rather than submit their children to numerous vaccinations as required by state laws, due to lobbying by vaccine manufacturers, as a condition of being in school.{{cn}}

== Mechanism ==

== Mechanism ==