Trial of a reduced dose of measles vaccine in Nigerian children.
To evaluate the effectiveness of measles vaccine in reduced dosage, Schwarz live, further attenuated measles virus vaccine was given in various doses by jet injector to 967 seronegative children aged 7-30 months in rural villages in the Northwest State of Nigeria. For children over 12 months of age, reducing vaccine virus dosage by 40%, 60%, or 80% led to progressive and statistically significant reductions in the seroconversion rates from 89% in children receiving the full dose to a minimum value of 46%. Reducing the volume of the inoculum below the standard of 0.5 ml resulted in a further reduction of seroconversion rates at each antigen dose level. Seroconversion rates in all dosage groups were lower for children below 12 months of age. These data suggest that dose reduction would not be a satisfactory economy measure in measles vaccination campaigns.
D000914:Antibodies, Viral / Q000032:analysis; D002675:Child, Preschool; D006801:Humans; D007223:Infant; D008457:Measles / Q000276:immunology / Q000517:prevention & control*; D008458:Measles Vaccine / Q000008:administration & dosage*; D009549:Nigeria; D014613:Vaccines, Attenuated / Q000008:administration & dosage
D000914:Antibodies, Viral; D008458:Measles Vaccine; D014613:Vaccines, Attenuated