Evaluation of Combination Measles-Mumps-Rubella-Varicella Vaccine Introduction in Australia

Abstract

Some parents and health care workers are finding decision making regarding immunization increasingly complex, presenting a barrier to timely vaccine uptake.^1,2 A commonly reported concern is the number of injections given to children.^1,2 Combination vaccines reduce the number of injections needed and may improve vaccine acceptance, coverage, and, ultimately, disease control. However, various other factors surrounding use of combination vaccines, including cost-effectiveness, safety, availability, and country- or region- specific disease epidemiology, require consideration.³ In the past decade, several countries have faced challenges in incorporating the combination measles-mumps-rubella-varicella (MMRV) vaccine into their immunization schedules. Although both available MMRV vaccines (Priorix-Tetra [GlaxoSmithKline Biologicals SA] and ProQuad [Merck & Co Inc]) offer the advantage of a single injection against 4 diseases, prelicensure studies showed an increased risk of fever in first-dose recipients aged 12 to 23 months compared with children who received measles-mumps-rubella (MMR) and varicella vaccines separately.^4,5 This reaction was presumed to be related to potentiation of the immune response to the measles virus component. Postlicensure studies subsequently reported an approximately 2-fold increased risk of febrile seizures (FSs) following MMRV compared with giving separate MMR and varicella vaccines.^6,7 This finding prompted a withdrawal of a preferential recommendation for use of MMRV as the first measles-containing vaccine (MCV) in the United States and Germany.^8,9