MMRV vaccine elevates risk of febrile seizures

Reactions 1310 - 17 Jul 2010 MMRV vaccine elevates risk of febrile seizures The combination measles, mumps, rubella and varicella (MMRV) vaccine elevates the risk of fever and seizure during the 7–10 days after vaccination, compared with separate administration of the MMR plus varicella vaccines, shows a US-based study. The study population comprised 83 107 infants (aged 12 23 months) vaccinated with MMRV between January 2006 and October 2008, and 376 354 infants vaccinated with MMR plus varicella on the same day between January 2000 and October 2008. After vaccination with all measles-containing vaccines, seizure incidence peaked during days 7 to 10 postvaccination, with the most prominent peak recorded after MMRV vaccination. Primary analysis revealed that, compared with separate MMR plus varicella vaccination, the MMRV combination vaccine was associated with a significantly higher seizure risk during days 7 10 postvaccination (RR 1.98; 95% CI 1.43, 2.73). Vaccination with MMRV would result in one additional febrile seizure for every 2300 doses given instead of separate MMR plus varicella vaccines. Putting it all in perspective Commenting on these results, the study’s lead investigator Dr Nicola Klein says that providers recommending MMRV "should communicate to parents that it increases the risk of fever and febrile seizure over that already associated with measles-containing vaccines". However, she notes that parents must understand that the risk for febrile seizures after vaccination is low, at "less than 1 febrile seizure per 1,000 injections". Dr Randy Bergen, a Kaiser Permanente paediatrician, also comments that "it is more common...