Editing Immunization (section)

=== Internalizing the externality ===
In order to internalize the positive externality imposed by immunizations payments equal to the marginal benefit must be made. In countries like the United States these payment usually come in the form of subsidies from the government. Before 1962 immunization programs in the United States were run on the local and state level of governments. The inconsistency in subsidies lead to some regions of the United States reaching the socially optimal quantity while other regions were left without subsidies and remained at the private marginal benefit level of immunizations. Since 1962 and the [[Vaccination Assistance Act]], the United States as a whole has been moving towards the socially optimal outcome on a larger scale.<ref>{{Cite web|url=https://www.cdc.gov/mmwr/preview/mmwrhtml/su6004a9.htm|title=Vaccine-Preventable Diseases, Immunizations, and MMWR – 1961–2011|website=www.cdc.gov|language=en|access-date=2018-03-07|archive-date=2018-05-06|archive-url=https://web.archive.org/web/20180506132751/https://www.cdc.gov/mmwr/preview/mmwrhtml/su6004a9.htm|url-status=live}}</ref> Despite government subsidies it is difficult to tell when social optimum has been achieved. In addition to hardships determining the true social marginal benefit of immunizations we see cultural movements shifting private marginal benefit curves. [[Vaccine controversies]] have changed the way some private citizens view the marginal benefit of being immunized. If Individual A believes that there is a large health risk, possibly larger than the antigen itself, associated with immunization they will not be willing to pay for or receive immunization. With fewer willing participants and a widening marginal benefit reaching a social optimum becomes more difficult for governments to achieve through subsidies.

Outside of government intervention through subsidies, non profit organizations can also move a society towards the socially optimal outcome by providing free immunizations to developing regions. Without the ability to afford the immunizations to begin with, developing societies will not be able to reach a quantity determined by private marginal benefits. By running immunization programs organizations are able to move privately under-immunized communities towards the social optimum.