Edmonston-B measles vaccine

Nearly every American child had measles by the age of 15. An estimated 3 to 4 million people in the United States were infected each year, and about 500,000 cases were reported annually. Among reported cases, an estimated 400 to 500 people died each year, 48,000 were hospitalized and 1,000 developed encephalitis. When measles first became a nationally notifiable disease in 1912, deaths in the first decade of reporting averaged 6,000 a year.

In 1954 John F. Enders and Thomas C. Peebles collected blood from sick students during a measles outbreak in Boston, hoping to isolate the virus and make a vaccine. They isolated it from the blood of 13-year-old David Edmonston. Enders and his colleagues turned the Edmonston-B strain into a live, weakened vaccine, and in 1963 it was licensed in the United States together with an inactivated, or killed, vaccine.

Neither 1963 product lasted. The inactivated vaccine protected poorly and was withdrawn in 1967, and the Edmonston-B vaccine caused fever and rash in a fairly high share of recipients and was withdrawn in 1975. A further weakened Schwarz strain vaccine appeared in 1965 but is no longer used in the country. From 1968 a still weaker vaccine developed by Maurice Hilleman and colleagues, the Edmonston-Enders strain, formerly called Moraten, was distributed, and it has been the only measles vaccine used in the United States since then. A combined measles, mumps and rubella vaccine was licensed in 1971.

After licensure, measles incidence fell by more than 95 percent. In 1978 CDC set a goal of eliminating the disease by 1982; the target was missed, and measles in vaccinated schoolchildren during the 1980s led to a recommendation for a second dose. Measles was declared eliminated from the United States in 2000, meaning it had not spread continuously in the country for more than 12 months.