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Evidence for reinstatement of infants 12 to 14 months of age into routine measles immunization programs
Insights
Infants aged 12-14 months achieve strong measles immunity with vaccines, comparable to older children. This study supports earlier measles vaccination, not delaying it to 15 months.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Measles remains endemic in the United States, posing risks to unvaccinated populations.
- Current recommendations suggest delaying routine measles vaccination until 15 months of age.
Purpose of the Study:
- To evaluate the serologic response to measles vaccine in infants and children.
- To determine the efficacy of measles vaccination at different ages, specifically 12-14 months versus 15 months and older.
Main Methods:
- A ten-year evaluation of hemagglutination inhibition (HI) serologic responses in 851 measles-susceptible infants and children.
- Analysis of vaccine response based on age at inoculation, with 23-day intervals.
Main Results:
- Infants vaccinated between 12-14 months showed seroconversion rates comparable to those vaccinated at 15 months or older.
- HI assay results indicate robust immune response across the evaluated age groups.
Conclusions:
- The findings challenge the recommendation to postpone routine measles immunization until 15 months of age.
- Vaccinating infants at 12-14 months is supported, mitigating risks during endemic measles periods.
- Further research is needed to understand vaccine failures post-maternal antibody loss.
Abstract:
The hemagglutination inhibition (HI) serologic responses of 851 measles-susceptible infants and children to the live, further-attenuated measles virus vaccine were evaluated over a ten-year period. The response by age at 23-day intervals was determined. Infants inoculated at 12 through 14 months of age demonstrated seroconversion rates by HI assay comparable to those in infants and children inoculated at 15 months of age or older. This finding does not support the recent recommendation that routine active immunization with measles vaccine should be postponed until 15 months of age. We emphasize the possible consequence of electively leaving infants 12 throught 14 months of age vulnerable to measles because of the current endemicity of this disease in the United States. We also present evidence for the reinstatement of infants 12 through 14 months of age into routine measles immunization programs and for the need to further evaluate the causes for vaccine failure in vaccines after the loss of maternal antibody.