Reactogenicity and immunogenicity of a new live attenuated combined measles, mumps and rubella vaccine in healthy children

Objective. To compare the reactogenicity and immunogenicity of a novel live attenuated measles-mumps-rubella vaccine, SE MMR (Priorix; SmithKline Beecham Biologicals), with a widely used MMR vaccine, Merck MMR (M-RI-R II; Merck & Co. Inc). Methods, A total of 4702 healthy children, ages 9 to 24 months, were enrolled in 8 single blind, randomized, controlled trials. Reactogenicity (local and general solicited symptoms and all unsolicited symptoms) was assessed for up to 42 days postvaccination, Immunogenicity [seroconversion rates and geometric mean titers (GMT)] was assessed at 42 or 60 days postvaccination in 1912 subjects in 7 studies. In two studies the persistence of the antibodies at Month 12 postvaccination. was assessed in 201 subjects. Results, Local symptoms (pain on or immediately after injection; pain, redness and swelling within 4 days of injection) were reported less frequently after SE MMR than Merck MMR (P < 0.0001). General symptoms and all other events were similar between the two groups. Fever >39.5 degrees C was reported after 9.5 and 11.9% of the SE MMR and Merck MMR doses, respectively, At Days 42 to 60 postvaccination seroconversion rates for antimeasles antibodies were higher with SE MMR than with Merck MMR (98.7% vs. 96.9% P < 0.031) but similar in both groups for anti-mumps and anti-rubella antibodies, GMTs being similar to 10% higher (P < 0.05) with Merck MMR than with SE MMR, At the Month 12 assessment the seropositivity rates and GMTs were similar in both groups. Conclusion, When administered as primary vaccination in children in the second year of life, the new SE MMR vaccine has been shown to be superior to a comparator vaccine in terms of local reactogenicity, with equivalent immunogenicity.