Booster immune response in children 6-7 years of age, randomly assigned to four groups with two MMR vaccines applied by aerosol or by injection.

IMPORTANCE

Aerosol immunization may be a useful tool to reach and sustain the elimination of measles, rubella, and congenital rubella syndrome. We compared booster seroresponses to aerosolized or injected MMR vaccines containing different strains of measles (Attenuvax or Edmonston-Zagreb) and mumps (Jeryl-Lynn or Leningrad-Zagreb).

OBJECTIVE

To assess the safety and immunogenicity of two MMR: Vaccines administered by aerosol.

METHODS

A randomized and controlled clinical trial was conducted to evaluate the safety and booster responses to the MMR SII (Serum Institute of India) and MMR II (Merck Sharp & Dhome) vaccines, both of which were administered by aerosol (ae) or injection (inj) to Mexican children aged 6-7 years in elementary schools. The seroresponses were evaluated by PRN (measles) and ELISA (rubella and mumps). Adverse events were followed-up for 28 days after the immunization.

RESULTS

Two hundred and fifty-three of 260 children completed the one-month follow-up. All participants reached protective seropositivity for measles and rubella after immunization, and 98.3 to 100% reached protective seropositivity for mumps (p=0.552). The proportions of the seroresponses (a 2-fold rise from the baseline antibody titers) to measles were 38.3% for MMR SII (ae), 31.3% for MMR II (ae), 37.5% for MMR SII (inj), and 44.6% for MMR II (inj) (p=0.483). The seroresponses for rubella were 26.7% for MMR SII (ae), 31.3% for MMR II (ae), 46.9% for MMR SII (inj), and 40.0% for MMR II (inj) (p=0.086). The seroresponse to mumps were 31.7% for MMR SII (ae), 25.0% for MMR II (ae), 48.4% for MMR SII (inj), and 53.9% for MMR II (inj) (p=0.002). The difference in the seroresponse of a 4-fold rise from the baseline antibody titers was not statistically significant. Only mild adverse events were noted.

CONCLUSION

Aerosolized vaccines were as safe and as immunogenic as injected vaccines.

PROTOCOL REGISTRATION: CMN 2010-005 (National Regulatory Authority).