title: Increasing the time of exposure to aerosol measles vaccine elicits an immune response equivalent to that seen in 9-month-old Mexican children given the same dose subcutaneously.
abstract: BACKGROUND
  A 30-second aerosol measles vaccination successfully primes children 12 months of age and older but is poorly immunogenic when given to 9-month-old children. We examined the immune responses when increasing the duration to aerosol exposure in 9-month-olds.
  
  
  METHODS
  One hundred and thirteen healthy 9-month-old children from Mexico City were enrolled; 58 received aerosol EZ measles vaccine for 2.5 minutes and 55 subcutaneously. Measles-specific neutralizing antibodies and cellular responses were measured before and at 3 and 6 months postimmunization.
  
  
  RESULTS
  Adaptive immunity was induced in 97% after aerosol and 98% after subcutaneous administration. Seroconversion rates and GMCs were 95% and 373 mIU/mL (95% confidence interval [CI], 441-843) following aerosol vaccination and 91% and 306 mIU/mL (95% CI, 367-597) after subcutaneous administration at 3 months. The percentage of children with a measles-specific stimulation index ≥3 was 45% and 60% in the aerosol versus 55% and 59% in the subcutaneous group at 3 and 6 months, respectively. CD8 memory cell frequencies were higher in the aerosol group at 3 months compared with the subcutaneous group. Adverse reactions were comparable in both groups.
  
  
  CONCLUSIONS
  Increasing exposure time to aerosol measles vaccine elicits immune responses that are comparable to those seen when an equivalent dose is administered by the subcutaneous route in 9-month-old infants.
authors: Facultad de Medicina, Departamento de Medicina Experimental, Universidad Nacional Autónoma de México. rmwong@unam.mx
authors: Rosa María
authors: RM
authors: Wong-Chew
authors: Miguel Leonardo
authors: ML
authors: García-León
authors: Bogart
authors: B
authors: Espinosa-Torres Torrija
authors: Brenda
authors: B
authors: Hernández-Pérez
authors: Lino E
authors: LE
authors: Cardiel-Marmolejo
authors: Judy A
authors: JA
authors: Beeler
authors: Susette
authors: S
authors: Audet
authors: José Ignacio
authors: JI
authors: Santos-Preciado
mesh_terms: D056704:Adaptive Immunity; D000336:Aerosols; D000914:Antibodies, Viral / Q000097:blood*; D005260:Female; D006801:Humans; D007223:Infant; D007371:Interferon-gamma / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008297:Male; D008458:Measles Vaccine / Q000008:administration & dosage* / Q000276:immunology; D008800:Mexico; D013601:T-Lymphocytes / Q000276:immunology; D013997:Time Factors; D014611:Vaccination
chemical_list: D000336:Aerosols; D000914:Antibodies, Viral; D008458:Measles Vaccine; D007371:Interferon-gamma