Changes

The USA has mandatory vaccination according to an official CDC schedule. Enforcement is left to the states. Most states have medical and religious exemptions. Some states make it very easy to opt out of vaccines, while other states strictly enforce compliance for school attendance. The difference in vaccination rates between these states is actually very slight, and not nearly enough to affect herd immunity.   

The USA has mandatory vaccination according to an official CDC schedule. Enforcement is left to the states. Most states have medical and religious exemptions. Some states make it very easy to opt out of vaccines, while other states strictly enforce compliance for school attendance. The difference in vaccination rates between these states is actually very slight, and not nearly enough to affect herd immunity.   

===Loss of Herd Immunity in the United States===

Measles has been eliminated from the USA, and the USA maintains herd immunity for measles, even in states where it is easy to opt out of vaccination requirements. Occasionally a case comes in from overseas travel, but the impact is minimal and no one has died from measles in years.<ref> [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5708a3.htm]</ref>

In February of 2008, an outbreak of [[measles]] occurred in [[San Diego]].  This outbreak was a result of the loss of herd immunity.  Due to the relaxed statutes in [[California]], many children in the San Diego community went unvaccinated.  One of these children, a boy, contracted measles in Sweden, return to the United States and caused the outbreak.  During this time, dozens of children contracted the disease and many were hospitalized with fevers reaching 104 degrees. These hospitalizations included a 3 month old baby who nearly died of dehydration.  The parents of the unvaccinated boy were unapologetic for nearly killing the other children, instead feeling their fears of vaccines were sufficient reason to endanger the lives of many.  The fear of the [[MMR]] vaccine (a vaccine against [[measles]], [[mumps]] and [[rubella]]), which no longer has mercury in it, continues to this day, with the vaccine being wrongly accused of causing [[autism]].<ref> [http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5708a3.htm]</ref>

== Adverse Reactions ==

== Adverse Reactions ==