Vaccination policies are health rules implemented by governments, schools, or workplaces to prevent infectious disease spread, ranging from mandatory requirements to strong recommendations. Their primary goals include achieving herd immunity—which protects vulnerable populations—and even eradicating diseases, as demonstrated by the global eradication of smallpox (last naturally occurring case in Somalia in 1977) and the ongoing WHO effort to eliminate polio, which remained only in Pakistan and Afghanistan after being cleared from Africa in 2020. These policies are often justified by economic incentives, as cost-benefit analyses show vaccines save states money by reducing healthcare burdens, and they are typically guided by advisory bodies like the CDC or ECDC. However, a core challenge lies in individual versus group goals: using game theory, researchers have shown that as vaccination rates rise and disease threats drop, individuals may logically choose to refuse vaccines, which can undermine community immunity. Globally, vaccines prevent an estimated 2–3 million deaths each year from diseases like measles and diphtheria, yet vaccine-preventable illnesses still claim around 3 million children annually, highlighting the delicate balance needed to design effective and broadly accepted policies.