New study shows higher risk of febrile seizures from combo vaccine in infants but still a minuscule risk

By ACSH Staff — Jun 10, 2014
Giving a combination vaccine, MMR-V (MMR plus varicella-chickenpox) vaccines at one time as opposed to separately, increases the risk of febrile seizures in infants. But the absolute risk is extremely low either way, much lower than the risk of measles, and such seizures have no significant sequelae.

Measles is Back!A large Canadian study shows that infants who receive the MMR vaccine (protective against measles, mumps and rubella) and at the same visit receive the varicella (chickenpox) vaccine termed MMRV have an approximately double the risk of febrile seizures within the 7-10 days thereafter, as compared with those who got the 2 shots separately (MMR+V). However, the absolute rate of such transient, self-limited seizures is minuscule, whether occurring after MMRV or MMR+V.

The group of researchers from the University of Alberta branches in Calgary and Edmonton, was led by Dr. Shannon MacDonald. They studied data from 277,774 children between 12 and 23 months who received either the combined MMRV vaccine or separate MMR+V vaccines. Alberta, where the study was conducted, replaced the separate vaccines with the combined vaccine in 2010. Nine of 13 Canadian provinces and territories administer the combined vaccine as part of their routine childhood immunization schedule. In Ontario, children are given separate vaccines for the first dose and the combined vaccine when they are between four and six years old. The rate of febrile seizures in infants given only MMR is about 2 per 10,000 patients; if given MMRV, the rate increases to almost 4 per 10,000.

ACSH s Dr. Gilbert Ross had this comment: Parents should not be dissuaded from getting their kids vaccinated against MMR and chickenpox by this scary headline. First, the actual rate of such seizures is barely there; next, these febrile seizures last for a very short time, and resolve without any long-lasting effect; they can be caused by any febrile illness, especially including the viral contagions protected against by these vaccines; and lastly, the specter of recurring contagious diseases is a real one, and they can do real long-term harm, even kill in rare cases. Only last month, the CDC announced that measles cases had soared to a new, 20-year high. That is largely thanks to the anti-vaccine activists whose ignorant diatribes are helping to stoke the flames of new dangerous outbreaks and epidemics.

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