SEROCONVERSION RATES TO COMBINED MEASLES-MUMPS-RUBELLA-VARICELLA VACCINE OF CHILDREN WITH UPPER RESPIRATORY-TRACT INFECTION

Objective. To determine if upper respiratory tract infection (URI) aff ects the seroconversion rate or quantitative response to each componen t of a combined measles-mumps-rubella-varicella vaccine. Subjects and methods. One hundred forty-nine children between 15 and 18 months of a ge were prospectively divided into two groups according to the presenc e of URI or recent history of URI symptoms within the 4 weeks before v accination. Once stratified, 74 children in the healthy group and 75 c hildren in the URI group were randomly assigned to receive one of thre e lots of measles-mumps-rubella varicella vaccine by subcutaneous inje ction into the deltoid area. Serum was obtained from each child just b efore vaccination and 4 to 6 weeks later for measuring antibody levels against each virus. Results. Prevaccination antibody levels against e ach virus in the URI and healthy groups did not differ. Nine children had pre-existing antibodies to varicella and six to mumps; no child ha d positive serologies for measles or rubella before vaccination. Child ren with pre-existing antibody were excluded from analysis of seroconv ersion for that virus. Seroconversion to measles, mumps, and rubella o ccurred in 100% of children in both groups. Mean antibody levels did n ot differ between the healthy and URI groups for measles (111 vs 122), mumps (97 vs 108), or rubella (96 vs 102). Three (4%) of 70 children with URIs in whom varicella serologies were available failed to seroco nvert to varicella vaccine although none of the 69 healthy children ha d vaccine failure (P = .24). The mean varicella antibody level was 11. 3 +/- 1.4 in the healthy children, which did not differ significantly from the level of 9.5 +/- 0.9 in the URI group.Conclusions. Seroconver sion to measles, mumps, rubella, and varicella was not significantly a ffected by the presence of a concurrent or recent URI in 15- to 18-mon th-old children.