Changes

Perhaps the most successful example of using contact tracing to diminish the effects of a disease is the example of smallpox, which was mostly eradicated by 1980 (Figure 2). This was mainly due to efforts of contact tracing, by isolating and treating infected individuals, and then also focus immunization efforts for people nearby, thereby focusing available resources to those who most urgently need immunization. The World Health Organization (WHO) perhaps established one of the largest contact tracing programs that now focused on the entire world. From the 1950s-1970s, contact tracing was used in developed and developing countries, where teams of volunteers, doctors, and individuals would go and interview people to determine the likely place in which an outbreak was present. This helped to track all major areas of smallpox that eventually led to its near eradication. The combination of a vaccine and contact tracing made this among the most successful, large-scale WHO efforts.<ref>For more on the success of smallpox contact tracing, see: McGuire-Wolfe, Christine. <i>Foundations of Infection Control and Prevention</i>. Burlington, MA: Jones & Bartlett Learning, 2018, pg. 11. </ref>

Contact tracing has transformed public health and epidemiology since its inception. The most recent advances have to do with the use of mobile phone data. The 2014 Ebola outbreak and 2015 MERS outbreak shaped South Korea's and some other Asian countries' experience with a major viral outbreak. The use of mobile phones and tracing someone's whereabouts was used under powers issued to the government. This experience helped South Korea and other east Asian countries pioneer the use of such data to track how individuals movements may affect the transmission of an infectious disease. While this was used initially in the Ebola and MERS outbreaks, the use in the 2020 COVID-19 outbreak proved essential for South Korea, China, and other east Asian countries in limiting the overall impact of COVID-19. While the use of mobile data for Western states is only now being applied, it also remains controversial given concerns over location data and personal data sharing with government authorities. Nevertheless, it is clear from the history of contact tracing, even without the use of mobile phones, tracking someone's whereabouts and the likely community in which they could spread infection to is critical in reducing infection rates. The example of syphilis, cholera, tuberculosis, and smallpox all demonstrate this even without the use of mobile phones.<ref>For more on recent contact tracing technology and application, see: Mittelstadt, Daniel Brent. <i>The Ethics of Biomedical Big Data</i>. New York, NY: Springer Berlin Heidelberg, 2016, pg. 26.</ref>