No link found between measles vaccine and autism
Yet another study has found that there is no link between the vaccination for measles, mumps and rubella and autism, even among children who are at high risk for the disorder.
The study sought to report the occurrence of autism spectrum disorders (ASD) among American children who have older siblings with and without ASD. The children received either no dose, one dose, or two doses of the MMR vaccine between birth and the age of 5. The researchers found that, of 95,727 children with older siblings, 994 (1.04 percent) were diagnosed with ASD, and 1,929 (2.01 percent) had an older sibling on the spectrum.
Of the children with an older sibling with ASD, 134 (6.9 percent) had ASD, compared with 860 (0.9 percent) of those with a sibling not on the spectrum.
The researchers also found that there was no association between the MMR vaccine and an increased risk of ASD at any age.
According to the study, surveys of parents who have children with ASD suggest that many believe that the MMR vaccine, which is given in two doses -- one between 12 to 15 months and the second between 4 to 6 years of age -- was a contributing cause. A 2012 study published in the journal Clinical Pediatrics found that, of 468 parents of children with ASD, 20 percent declined or delayed MMR immunization for their younger children.
The new study was published in the Journal of the American Medical Association (JAMA).
"Hopefully this study is reassuring that there isn’t any additional risk from the vaccine," said lead author Dr. Anjali Jain, a pediatrician and vice president at The Lewin Group.
Before the measles vaccine was licensed in 1963, there were an estimated 3 to 4 million cases each year. Since 1963, the number of cases dropped significantly, with only 1,497 cases two decades later. In 2004, a record low of 37 cases of measles were reported. Ten years later, the U.S. experienced 644 cases in 27 states, the greatest number of cases since measles elimination was documented in 2000.
From January to April 17 of this year, there have been 162 reported cases of measles in 19 states and the District of Columbia. Seventy-two percent of those cases are part of a large multi-state outbreak linked to Disneyland in California, which most likely started from a traveler who became infected overseas and then visited the amusement park while infectious.