Routine immunization against measles, mumps, rubella, and rubella, also known as the rubella or measles virus, is generally believed to be essential for the prevention of infectious diseases, and has been part of routine childhood immunizations since the 1970s.
Although individual countries like the United States and Europe have a strong track record in timely childhood immunization coverage, results from the first-ever measles vaccination index published by the World Health Organization show that measles rates are falling at a slower rate than was thought possible.
“Measles was considered a vaccine success story,” says Sy Zayyad, president of the American Academy of Pediatrics (AAP). “If we had started a measles program in the United States, we would be still talking about it 20 years from now. If we look at the problems in the United States, like lack of funding, lack of availability and issues about religious exemptions, we can’t continue to say there’s no resistance to vaccinations in the United States.”
Measles is a highly contagious disease that has been in decline for decades. To understand how the success story unfolded, it helps to look at the development of measles between 1970 and 2015. (Measles is classified into three groups, depending on the severity of illness and the time interval between exposures. Because vaccines can help protect from measles in fewer years, it’s important to count people who’ve been exposed to the virus and then vaccinated themselves or their children.)
Measles outbreaks in the United States and other developed countries began falling steeply in the late 1970s, a decade before the WHO began using data on the measles death index, a tool for assessing the rate of incidence of measles in people up to five years of age.
The WHO began tracking countries’ measles death index numbers in 1985. The highest global death rate from measles during that period was 15 deaths per 100,000 people. But between 2000 and 2015, the number of deaths dropped by over 80 percent.
The decline likely reflected the availability of a vaccine for measles and childhood immunity levels, which were high enough to decrease the number of cases due to existing immunity. In 2003, the WHO introduced regional comparisons of children’s survival due to measles, making it easy to understand why measles deaths continued to fall in many parts of the world even as vaccine coverage remained high, even if there were still outbreaks.