Two measles-containing vaccines are unlikely to result in adverse effects, a 12-year study has found.
Researchers from the Kaiser Permanente Vaccine Study Center evaluated the effects of 123,200 doses of measles-mumps-rubella-varicella (MMRV)vaccine and 584,987 doses of measles-mumps-rubella and varicella (MMR+V) vaccines (given separately on the same day) in children aged 12 to 23 months from 2000 to 2012 to determine whether MMRV posed more risk that MMR+V.
Risks for the 7 main study outcomes (anaphylaxis; immune thrombocytopenic purpura; ataxia; arthritis; meningitis and encephalitis; acute disseminated encephalomyelitis; and Kawasaki disease) didn’t differ significantly between MMRV and MMR+V, and several of the outcomes were associated with few or no postvaccination events. Researchers didn’t discover any new safety concerns for either vaccine course.
In line with previous research, the study found that MMRV and MMR+V both slightly increase the risk of fever and febrile seizures in 1-year-old children within 7 to 10 days after vaccination and that MMRV carries a higher risk than MMR+V. Fewer than 1 febrile seizure occurs for every 1000 immunizations.
The researchers conclude that the study findings provide reassurance that the safety outcomes they evaluated are “extremely rate and unlikely after either vaccine.”
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