Measles, mumps, rubella and varicella vaccines
Live attenuated measles, mumps and rubella (MMR) viruses contained in trivalent and measles, mumps, rubella and varicella (MMRV) in quadrivalent vaccines, are cultured in hen’s embryonic fibroblasts and might contain residual traces of ovalbumin. In the past, egg allergy has been suspected as a cause of hypersensitivity reactions to these vaccines but, currently, MMR and MMRV are considered safe for egg-allergic patients and they can be administered in standard settings1.
Some brands of MMR, MMRV and varicella vaccines may contain residual porcine or bovine gelatine as a stabilizer, which has been identified the responsible component in rare cases of anaphylaxis but also non-immediate systemic reactions such as skin symptoms are reported30. Consequently, in case of allergy to animal gelatine or to galactose-alpha-1,3-galactose (α-Gal) contained in mammalian meat, a gelatine-free vaccine is the first choice. When the latter is not available, in case of positive skin testing results, vaccines should be administered in fractionated doses (see above).