Measles reimmunization in children seronegative after initial immunization
G. A. Poland, R. M. Jacobson, A. M. Thampy, S. A. Colbourne, P. C. Wollan, J. J. Lipsky and S. J. Jacobsen
Mayo Vaccine Research Group, Mayo Clinic and Foundation, Rochester, Minn 55905, USA.
OBJECTIVE: To evaluate the success of measles reimmunization in children
without measles antibody after the initial dose of measles vaccine. DESIGN
AND SETTING: A prospective clinical trial in Olmsted County, Minnesota, and
Northern Newfoundland and Labrador in Canada. SUBJECTS: A total of 130
healthy white, Innu, and Inuit schoolchildren. All subjects had received
the post-1980 Moraten measles vaccine 4 to 11 years earlier. METHODS:
Children previously identified as measles antibody seronegative or
equivocal after 1 dose of measles vaccine were entered into the trial and
reimmunized. Measles antibody was measured a minimum of 6 weeks later using
a whole-virus IgG measles-specific enzyme-linked immunoassay (EIA).
RESULTS: Of the 130 children reimmunized, 106 (81.5%) became measles
antibody seropositive, but 24 children (18.5%) remained seronegative.
Younger age at initial immunization (<13 months vs > or = 13 months)
was significantly associated with lack of seropositive antibody levels
following reimmunization (odds ratio, 3.9; 95% confidence interval,
1.5-9.7). In addition, antibody levels after reimmunization were
significantly reduced with increasing time since initial immunization
(P=.001). CONCLUSIONS: After 2 doses of measles vaccine, 98.2% of all
subjects in this study were seropositive for measles antibody, despite the
fact that almost 20% of children did not have measurable antibodies 4 to 11
years following a first dose. These findings suggest that the current
public health policy recommending a 2-dose measles immunization strategy,
with the second dose given at school entry, will provide high levels of
immunity in the community.
