Title:
Association of the use of MMRV in infants by pediatric infectious disease specialists with that of other affiliated providers.

Abstract:
In an effort to maximize vaccine acceptance by minimizing adverse events following immunization associated with fever, including seizures, the Advisory Committee on Immunization Practices (ACIP) recommended in 2009 the use of measles, mumps and rubella vaccine (MMR) and varicella vaccines (V) given separately (MMR+V) rather than combination MMRV as the first dose of MMR-containing vaccine to infants. We evaluated factors associated with continued administration of MMRV as the first dose in many infants despite the ACIP recommendation.
Children 12 to 23 months of age who received MMRV or MMR+V between May 1, 2010 and April 30, 2011 were identified. Patient, provider and facility characteristics associated with MMRV or MMR+V administration were analyzed by bivariate and by multilevel multivariable logistic regression analysis.
Altogether, 30,017 children received the first dose of MMRV or MMR+V at 12 to 23 months of age between May 1, 2010 and April 30, 2011. Of these, 10.2% received MMRV while 89.8% received MMR+V. MMRV was more likely to be administered to children who were non-compliant with vaccine recommendations at age one (adjusted odds ratio=1.48, 95%CI=1.28, 1.71). In addition, administration of MMRV by a Pediatric Infectious Disease specialist affiliated with a clinic was significantly associated with an increased likelihood of administration of MMRV by other providers at that clinic (interval odds ratio 80=2.18, 675.94, P(OR>1)=95%).
These data suggest that while most providers followed the ACIP recommendation to administer MMR and V separately, Pediatric Infectious Disease specialists' vaccination practices may impact compliance with ACIP recommendations by other providers. Further study of the drivers behind the use of MMRV rather than MMR+V as the first dose of measles-containing vaccine is needed to determine if reinforcement or if clarification of ACIP recommendations is needed to elucidate when MMRV might be preferred over MMR+V.