33 countries. In the 1960s six to eight children died each year in the U.S. from vaccination-related complications. According to the WHO there were in 1966 about 100 million cases of smallpox worldwide, causing an estimated two million deaths. In the 1970s there was such a small risk of contracting smallpox that the U.S. Public Health Service recommended for routine smallpox vaccination to be ended. By 1974 the WHO smallpox vaccination program had confined smallpox to parts of Pakistan, India, Bangladesh, Ethiopia and Somalia. In 1977 the WHO recorded the last case of smallpox infection acquired outside a laboratory in Somalia. In 1980 the WHO officially declared the world free of smallpox. In 1974 the WHO adopted the goal of universal vaccination by 1990 to protect children against six preventable infectious diseases: measles, poliomyelitis, diphtheria, whooping cough, tetanus, and tuberculosis. In the 1980s only 20 to 40% of children in developing countries were vaccinated against these six diseases. In wealthy nations the number of measles cases had dropped dramatically after the introduction of the measles vaccine in 1963. WHO figures demonstrate that in many countries a decline in measles vaccination leads to a resurgence in measles cases. Measles are so contagious that public health experts believe a vaccination rate of 100% is needed to control the disease. Despite decades of mass vaccination polio remains a threat in India, Nigeria, Somalia, Niger, Afghanistan, Bangladesh and Indonesia. By 2006 global health experts concluded that the eradication of polio was only possible if the supply of drinking water and sanitation facilities were improved in slums. The deployment of a combined DPT vaccine against diphtheria, pertussis (whooping cough), and tetanus in the 1950s was considered a major advancement for public health. But in the course of vaccination campaigns that spanned decades, DPT vaccines became associated with high incidences of side effects. Despite improved DPT vaccines coming onto the market in the 1990s DPT vaccines became the focus of anti-vaccination campaigns in wealthy nations. As immunization rates fell outbreaks of pertussis increased in many countries. In 2000, the Global Alliance for Vaccines and Immunization was established to strengthen routine vaccinations and introduce new and underused vaccines in countries with a per capita GDP of under US$1000. Vaccination policy To eliminate the risk of outbreaks of some diseases, at various times governments and other institutions have employed policies requiring vaccination for all people. For example, an