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Evaluation of Wistar RA27/3 rubella virus vaccine in children
Abstract:
Because the Wistar RA27/3 strain rubella virus vaccine has potentially important advantages over rubella vaccines currently licensed in the United States, a field trial was conducted in Minnesota and Wisconsin in 1974 to evaluate RA27/3 in this country. Two hundred eighty-five (99.7%) of 286 susceptible children given RA27/3 subcutaneously seroconverted, with a geometric mean hemagglutination inhibition (HI) titer of 81.2. Twenty-eight (23%) of 122 children with rubella antibodies before immunization had fourfold or greater rises in rubella HI titers. The highest percentage of booster responses occurred in children with low preimmunization titers. Side effects were reported in 34% of subjects, but only one reaction associated with RA27/3 was serious: in a 5-year-old boy, arthritis of the left hip developed 31 days after immunization. This study indicates that RA27/3 vaccine produced a very high rate of seroconversion with high postimmunization HI titers. The ability to elicit significant booster responses in children with low levels of HI antibodies suggests that RA27/3 could be used to boost immunity in women of childbearing age whose rubella titers have declined to undetectable levels.
Insights
The Wistar RA27/3 rubella vaccine demonstrated high effectiveness in children, achieving excellent seroconversion rates. This rubella virus vaccine also showed potential for boosting immunity in adults with declining antibody levels.
Area of Science:
- Virology
- Immunology
- Vaccinology
Background:
- The Wistar RA27/3 rubella virus vaccine presents potential advantages over existing US-licensed rubella vaccines.
- Evaluating novel vaccine strains is crucial for improving public health interventions against rubella.
Purpose of the Study:
- To assess the efficacy and safety of the Wistar RA27/3 rubella vaccine in a US population.
- To determine the seroconversion rates and antibody responses following RA27/3 vaccination.
- To evaluate the vaccine's potential for boosting immunity in individuals with low rubella antibody titers.
Main Methods:
- A field trial involving 286 susceptible children in Minnesota and Wisconsin during 1974.
- Subcutaneous administration of the Wistar RA27/3 rubella vaccine.
- Measurement of hemagglutination inhibition (HI) titers to assess seroconversion and booster responses.
Main Results:
- A high seroconversion rate of 99.7% (285/286) was observed in susceptible children.
- A geometric mean HI titer of 81.2 was achieved post-immunization.
- Twenty-three percent of children with pre-existing antibodies showed a fourfold or greater rise in HI titers, particularly those with lower initial titers.
- A low incidence of serious side effects was reported, with one case of arthritis.
Conclusions:
- The Wistar RA27/3 vaccine elicits a high rate of seroconversion and robust post-immunization HI titers.
- The vaccine's ability to induce booster responses in individuals with low antibody levels suggests its utility for enhancing immunity, particularly in women of childbearing age.
- RA27/3 represents a promising rubella vaccine candidate for the United States.