Vaccines provide protection against a wide range of serious diseases. Diseases do not respect the boarders of countries, and contagious infections and diseases may reappear, however, if vaccination coverage decreases.
Immunization has proven to be one of the most cost-effective investments made in public health care (WHO, 2018). Immunization saves millions of lives, and it is also widely recognized as one of the most successful and cost-effective global health interventions. Vaccinating increases life expectancy. It saves millions of people from illness, secondary infections, infertility, disability and death each year. Various illnesses, infections and diseases cause suffering and pain. Therefore, financial resources are also required, such as resources in health care services, treatment days in hospitals, sick leaves, or days off from work to care for sick children.
Through vaccination, infectious diseases can be eradicated. One disease, smallpox (lat. variola), has been rooted out worldwide. WHO has reported that smallpox was eradicated globally in 1980.