Pandemic smallpox was responsible for 300–500 million deaths. As recently as the early 1950s, an estimated 50 million cases of smallpox occurred in the world each year. After successful vaccination campaigns throughout the 19th and 20th centuries, the WHO certified the eradication of smallpox in December 1979. To this day, smallpox is the only human infectious disease to have been completely eradicated, and one of two infectious viruses ever to be eradicated. Historically, measles was prevalent throughout the world, as it is highly contagious. According to the U.S. National Immunization Program, 90% of people were infected with measles by age 15.
Certified first responder be sent out in response to an emergency call. It is almost always required for professional and volunteer firefighters. For example, all firefighters of the New York City Fire Department require a valid CFR-D (Certified First Responder - Defibrillation) certification. The first responder level of emergency medical training is also often required for police officers, rescue squad personnel, and search and rescue personnel. Many first responders have location specific training such as water rescue or mountain rescue and must take advanced courses to be certified (i.e. lifeguard). Many people who do not fall into the earlier mentioned categories seek out