Measles Immunity After Revaccination: Results in Children Vaccinated Before 10 Months of Age

Abstract

Measles immunity was studied in children in a private pediatric practice who had been revaccinated because they had received their primary measles vaccination before 1 year of age. Antibody was measured in 72 of these children who had received the first injection of live measles virus vaccine at <10 months of age, and the second at >1 year of age. Of the 72 children, 29 (40%) had no detectable antibody and the geometric mean titer for the group was approximately 1:4. Of the children with low antibody titers, 15 were given a third injection of measles vaccine and five (33%) still did not respond. Cell- mediated immunity as indicated by lymphocyte transformation to measles antigen was measured in 11 of the children. Five (45%) had responses to measles antigen, but the responses did not correlate with the presence or absence of antibody. This study confirms the observation that revaccination is unsuccessful in many children who received measles vaccine in the first year of life, and shows that even a third injection of vaccine may fail to produce a significant antibody response.

Seroepidemiological Study of Measles Virus among Young Adults: Response to Revaccination

“…Of the studied population 23.8% were seronegative, and there was no difference between those who had 1 dose of vaccine and those who had 2 doses (Table-1).Reinfection and disease seem to occur in individuals who have previously had a measles immunization and when the titer has fallen below a critical level [16,20].Our results in Table-3 were found to be consistent with previous results; children vaccinated twice have better protection than single dose recipients [11,13]and inconsistent with others elsewhere;additional doses of vaccine could not boost the antibodies to a satisfactory level, and that any boosting that did take place was only short-lived [11,13]. Although the waning immunity after immunization may be a factor in previously immunized children seem to occur in people in whom response to the vaccine was inadequate [i.e.…”

“…[21].Seronegativity or vaccine failure may occur either because the immune response never developed or because it weaned over time [22].Changes in the age of vaccination and type ofvaccine used over past decades may impact on future epidemiology of measles through differing rates of waning immunity [23].It had been found that 40% of children who had received 2 doses of measles vaccine (first dose before 12 months of age) were seronegative, and 33% of the seronegative ones did not respond to a third dose of vaccine [13].While seroconversion rates in children after the first and second doses of measles vaccination at 9 and 15 months ofseroconvertion rates of 77.6% and 69.9% after the first dose and 81.9% and 90.3% after the second dose of measles vaccine [24].The SVF phenomenon due to waning immunity may become apparent only after the passage of years. It was suggested that vaccine-induced measles antibodies decline with time, and fall below protective levels [25].…”

“…The measles vaccine is, however, less immunogenic in the presence of maternal antibodies before 12 months of age [11]. The Immunization policy in Iraq follows the World Health Organization's recommendation for developing countries, and includes monocomponent vaccine against measles at 9 months of age [13]. In addition, vaccination against measles has been recommended for children aged 12-15 months in Iraq which was started in 1986 as a single measles antigen vaccine, then at 1988 MMR was introduced [14].…”