Vaccine combo increases risk of fever seizures in young kids

As if there weren’t enough controversy over children’s vaccines, here comes some more fodder for those opposed to inoculations.

Try to follow this because it gets complicated. (Maybe that’s why people are so mistrustful of vaccines. A recent analysis showed that 39 percent of parents surveyed said they delayed or refused to vaccinate their children.)

The Centers for Disease Control and Prevention’s Advisory Committee on Immunizations recommends that all children get immunized against measles, mumps, rubella (German measles), and varicella (chicken pox). For years that has entailed separate doses of the MMR vaccine and of the varicella vaccine given first at the ages of 12 months and 15 months and again at 4 years to 6 years.

Then in 2005 a combined MMRV vaccine was approved for use in the U.S. That vaccine, ProQuad made by Merck & Co., has been unavailable since September 2007 due to “manufacturing constraints,” according to the CDC. The agency says it expects the MMRV vaccine to become available again in the U.S. in May, 2010.

.On Thursday, the CDC reiterated the recommendations from its Advisory Committee on Immunization Practices that the combo MMRV vaccine not be used for the initial dose in children younger than four years of age because of an increased risk of seizures associated with high fevers. Instead the ACIP recommends that the first dose be given as an MMR vaccine and a separate varicella vaccine, unless the parent objects and wants only one shot

The CDC analyzed data on 43,353 children 12 months to 23 months who got the MMRV shot compared to 314,599 kids in the same age range who got the chicken pox vaccine and the MMR vaccine at the same doctor’s visit. Preliminary results showed that those who got the MMRV were more than two times as likely to have a “febrile seizure” though the actual numbers were low. Nine per 10,000 who got the MMRV had the fever induced seizures compared with four per 10,000 who got the MMR and varicella vaccines.

“Of the 166 children who experienced febrile seizures after vaccination and had hospitalization information available, 26 (16 percent) were hospitalized,” the CDC reported. None of the children who had the seizures died, according to the agency.

Summary of the CDC's recommendations for measles, mumps, rubella and varicella (MMRV) vaccine use:

  • The routinely recommended ages for measles, mumps, rubella and varicella vaccination continue to be age 12--15 months for the first dose and age 4--6 years for the second dose.
  • For the first dose of measles, mumps, rubella, and varicella vaccines at age 12--47 months, either measles, mumps, and rubella (MMR) vaccine and varicella vaccine or MMRV vaccine may be used. Providers who are considering administering MMRV vaccine should discuss the benefits and risks of both vaccination options with the parents or caregivers. Unless the parent or caregiver expresses a preference for MMRV vaccine, CDC recommends that MMR vaccine and varicella vaccine should be administered for the first dose in this age group.
  • For the second dose of measles, mumps, rubella, and varicella vaccines at any age (15 months--12 years) and for the first dose at age ≥48 months, use of MMRV vaccine generally is preferred over separate injections of its equivalent component vaccines (i.e., MMR vaccine and varicella vaccine). Considerations should include provider assessment, patient preference, and the potential for adverse events.
  • A personal or family (i.e., sibling or parent) history of seizures of any etiology is a precaution for MMRV vaccination. Children with a personal or family history of seizures of any etiology generally should be vaccinated with MMR vaccine and varicella vaccine.