[1][5] Most children do not experience any side effects;[6] those that do occur are usually mild, such as fever, rash, pain at the site of injection, and joint stiffness; and are short-lived.

[13] In that year, the Edmonston-B strain of measles virus was turned into a vaccine by John Enders and colleagues and licensed in the United States.

"[22] In the United States, reported cases of measles fell from 3 to 4 million with 400 to 500 deaths to tens of thousands per year following introduction of two measles vaccines in 1963 (both an inactivated and a live attenuated vaccine (Edmonston B strain) were licensed for use, see chart at right).

[29] The vaccine for measles led to the near-complete elimination of the disease in the United States and other developed countries.

[30] While the vaccine is made with a live virus which can cause side effects, these are far fewer and less serious than the sickness and death caused by measles itself; side effects ranging from rashes to, rarely, convulsions, occur in a small percentage of recipients.

[33] Of the 66 cases of measles reported in the U.S. in 2005, slightly over half were attributable to one unvaccinated teenager who became infected during a visit to Romania.

[36] A high-titre vaccine resulted in worse outcomes in girls, and consequently is not recommended by the World Health Organization.

[37] The immune response to the measles vaccine can be impaired by the presence of parasitic infections such as helminthiasis.

[43] Adverse effects associated with the MMR vaccine include fever, rash, injection site pain, and, in rare cases, red or purple discolorations on the skin known as thrombocytopenic purpura, or seizures related to fever (febrile seizure).

[46][47][48][45] Some people shouldn't receive the measles or MMR vaccine, including cases of: John Franklin Enders, who had shared the 1954 Nobel Prize in Medicine for work on the polio virus, sent Thomas C. Peebles to Fay School in Massachusetts, where an outbreak of measles was underway; Peebles was able to isolate the virus from blood samples and throat swabs, and was later able to cultivate the virus and show that the disease could be passed on to monkeys inoculated with the material he had collected.

[30] Enders was able to use the cultivated virus to develop a measles vaccine in 1963 by attenuation through cultured chicken embryo fibroblasts of the material isolated by Peebles.

[54] In the mid-20th century, measles was particularly devastating in West Africa, where child mortality rate was 50 percent before age five, and the children were struck with the type of rash and other symptoms common prior to 1900 in England and other countries.

[citation needed] The first trial of a live attenuated measles vaccine was undertaken in 1960 by the British paediatrician David Morley in a village near Ilesha, Nigeria;[55] in case he could be accused of exploiting the Nigerian population, Morley included his own four children in the study.

The encouraging results led to a second study of about 450 children in the village and at the Wesley Guild Hospital in Ilesha.

[59] The measles component of the MMR vaccine uses Attenuvax,[60] which is grown in a chick embryo cell culture using the Enders' attenuated Edmonston strain.

[60] Following ACIP recommendations, Merck decided not to resume production of Attenuvax as standalone vaccine on 21 October 2009.