No Seizure Risk From Measles Vaccine in Older Children A large new study has ruled out concerns that children over 4 are at greater risk of seizures after getting a common measles-containing vaccine called MMRV. The vaccine - which combines the shot for measles, mumps and rubella, or MMR, with the vaccine for varicella, or chickenpox - is given to children in two steps, first as toddlers and then again between ages 4 and 6. Concerns were raised several years ago after scientists found that 1-year-old children who were given the MMRV vaccine had double the risk of a febrile seizure, a brief convulsion triggered by a fever, compared with those who were given the MMR and chickenpox shots separately but on the same day. Febrile seizures, which can also be set off by ear infections, colds and other viral illnesses, strike about 5 percent of children younger than 5 and are particularly common in toddlers. Although they are alarming to parents, they do not cause any long-term problems. The earlier findings in toddlers raised concerns that children who got the combined shot later on might also be at greater risk of febrile seizures. But the new study, financed by the Centers for Disease Control and Prevention and published in the journal Pediatrics, found that that was not the case. Looking at more than 150,000 children who were vaccinated from 2000 to 2008, the researchers found that there was no increased risk of febrile seizures in older children who were given either the combined MMRV shot or the MMR and chickenpox vaccines separately. "This is a very reassuring study," said Dr. Nicola Klein, the lead author of the paper and co-director of the Kaiser Permanente Vaccine Study Center. The MMRV shot became widely available in 2006, allowing multiple vaccines to be bundled into one injection. But four years later a study, also published in Pediatrics, pointed out the increased risk of febrile seizures in toddlers, prompting the C.D.C. to recommend that parents opt for the separate MMR and chickenpox shots when immunizing younger children. Although febrile seizures are more likely with the combined shot at that younger age, the risk is still low, occurring in one of every 2,300 toddlers receiving it. In the latest study, the number of such reactions was even lower. In the 10 days after vaccination, only one of the 86,750 4- to 6-year-olds who were given the MMRV shot experienced a febrile seizure. Meanwhile, there were no seizures in the 67,000 who received the MMR and chickenpox vaccines separately but on the same day. Dr. Klein said the pattern in which febrile seizures occur with age may have something to do with the higher risk among toddlers. "Febrile seizures peak around the age of 18 months," she said. When you start looking at older children, over all they have a much lower risk. That's just what happens.