ACIP adjusts recommendations on MMRV vaccine

The Advisory Committee on Immunization Practices recommended several adjustments to guidelines for administering the combination measles, mumps, rubella and varicella vaccine vs. separate component vaccines after assessing additional febrile seizure data presented at a meeting in Atlanta last week.

The changes are as follows:

Health care providers now have the option of administering either MMRV vaccine (Proquad, Merck) or separate MMR and varicella vaccines to children aged 12 months to 3 years for the first dose in the measles, mumps, rubella and varicella immunization schedule after discussing the benefits and risks of both options with parents or caregivers.
Physicians should defer to the ACIPs new general recommendations on combination vaccines — which state a preference for combination vaccines when safe and effective — for a first dose administered to children aged 4 to 12 years and for the second dose in the MMRV immunization schedule for children ages 4 to 6 years.

This replaces the ACIP stance adopted last year that favored separate but equivalent component vaccine administration as a precaution following evidence that suggested increased risk for febrile seizures in children who received the combination vaccine.

“This allows physicians and parents to make a decision that best suits a child’s individual situation,” Mona Marin, MD, a member of the CDC’s division of viral diseases said about the first-dose recommendations when she presented the policy options. But she also noted that providers may need more time to counsel parents about the options to help them weigh the evidence.

Benefits of the new second dose recommendations include:

Simplification and harmonization with general recommendations.
Fewer injections with combination MMRV vaccine can reduce pain and anxiety and may lead to more rapid increased coverage for dose-two varicella vaccine.

The new recommendations followed a lengthy discussion concerning the benefits and risks associated with both options.

Karen Broder, MD of the Immunization Safety Office at the CDC presented the vaccine safety working group’s risk assessment analysis. She explained that risk for febrile seizure was about two-fold greater among children aged 12 to 23 months during the one to two weeks following vaccination with the first dose of MMRV compared with children who received MMR vaccine plus varicella vaccine — a risk which equates to one additional febrile seizure per 2,300 to 2,600 children vaccinated.

However, she emphasized that children who experience febrile seizures generally have an excellent prognosis, and that greater than 90% do not develop epilepsy or other neurodevelopmental disorders. “The peak ages for febrile seizure are 14 months to 18 months, which overlaps with the recommendation for the first dose of MMRV,” Broder said.

Data suggest that children who experience febrile seizures after MMR vaccination are no more likely to experience a seizure than those whose seizures are attributable to other causes, according to Broder who cited data from studies previously published in the New England Journal of Medicine and the Journal of the American Medical Association. – by Nicole Blazek

For more information:

Broder K. Synthesis of evidence for febrile seizure risk after MMRV vaccination. Presented at: Advisory Committee on Immunization Practices Meeting. June 24-26, 2009; Atlanta