Changes

An important concept in vaccine planning is [[herd immunity]]. This is the idea that when a certain percentage of a population is vaccinated, those within the population who are not vaccinated are protected from the disease.  This is a fairly straight forward concept; if 90 percent of a population is immune, then the chances that a carrier of the disease will come into contact with a non-immune member of the population (or "herd") is low. <ref>http://www.mathepi.com/maindir/herd.html The mathematics of herd immunity</ref>. Herd immunity is the goal of most vaccination programs as it is the point where a disease can start to be eliminated altogether from a population.  

An important concept in vaccine planning is [[herd immunity]]. This is the idea that when a certain percentage of a population is vaccinated, those within the population who are not vaccinated are protected from the disease.  This is a fairly straight forward concept; if 90 percent of a population is immune, then the chances that a carrier of the disease will come into contact with a non-immune member of the population (or "herd") is low. <ref>http://www.mathepi.com/maindir/herd.html The mathematics of herd immunity</ref>. Herd immunity is the goal of most vaccination programs as it is the point where a disease can start to be eliminated altogether from a population.  

For example, in 1962 Japan instituted mandatory vaccination against influenza in school children. This continued until 1987 when the program was changed to optional and abandoned in 1994. Approximately 85 percent of children were estimated to have been vaccinated. <ref>http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=387431 Control of Influenza </ref> Several studies examined the mortality rates due to influenza during this period of time and revealed that the death rates due to influenza in all population groups was drastically decreased including older adult populations. Since there was no increased rate of vaccination in these populations the decreased mortality was caused by herd immunity effects of vaccinating so many children. <ref>http://www.newsrx.com/newsletters/Vaccine-Weekly/2001-04-11/200104113335VW.html Mandatory Vaccination of Japanese Schoolchildren Demonstrates "Herd Immunity" </ref> Many researchers have written that this and other evidence argues strongly for mandatory vaccination programs world wide as a means of controlling many diseases and preventing  a [[pandemic]].<ref> http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1360502 Herd Immunity</ref>

For example, in 1962 Japan instituted mandatory vaccination against influenza in school children. This continued until 1987 when the program was changed to optional; it was abandoned in 1994. Approximately 85 percent of children were estimated to have been vaccinated. <ref>http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=387431 Control of Influenza </ref> Several studies examined the mortality rates due to influenza during this period of time and revealed that the death rates due to influenza in all population groups was drastically decreased, including older adult populations. Since there was no increased rate of vaccination in these populations, the decreased mortality was caused by herd immunity effects of vaccinating so many children. <ref>http://www.newsrx.com/newsletters/Vaccine-Weekly/2001-04-11/200104113335VW.html Mandatory Vaccination of Japanese Schoolchildren Demonstrates "Herd Immunity" </ref> Many researchers have written that this and other evidence argues strongly for mandatory vaccination programs world wide as a means of controlling many diseases and preventing  a [[pandemic]].<ref> http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1360502 Herd Immunity</ref>

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.