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RA27/3 rubella vaccine. A four-year follow-up
Insights
The RA27/3 rubella vaccine provided durable immunity in children and adolescents, with rare reinfection and few adverse events over four years. This rubella immunization study shows long-lasting protection.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Rubella vaccination is crucial for preventing congenital rubella syndrome.
- The RA27/3 rubella vaccine strain has been widely used.
- Long-term efficacy and safety data for RA27/3 vaccine are important.
Purpose of the Study:
- To evaluate the four-year efficacy and safety of the RA27/3 rubella vaccine in children and adolescents.
- To assess rubella reinfection rates and vaccine-induced antibody persistence.
Main Methods:
- 418 subjects aged 1-17 years received RA27/3 rubella vaccine.
- A four-year follow-up study included 201 subjects.
- Immune response was assessed via hemagglutination-inhibiting (HI) and neutralizing (Nt) antibody titers.
Main Results:
- Two mild vaccine-associated complications were reported: transient arthritis and a skin macule.
- Rubella reinfection was uncommon (≤3 subjects).
- High seroconversion rates (186/186) and sustained HI titers (182/186) were observed at four years, with a geometric mean titer of 30.3.
Conclusions:
- The RA27/3 rubella vaccine demonstrated durable immunity and a favorable safety profile over four years.
- Low rates of rubella reinfection and secondary vaccine failure were noted.
- The vaccine effectively induces and maintains protective antibody levels in pediatric populations.
Abstract:
RA27/3 rubella vaccine was given to 418 subjects aged 1 to 17 years in 1974, 201 of whom participated in a four-year follow-up study. Two vaccine-associated complications were reported. A 5-year-old boy had transient arthritis of the hip, and a 1-year-old boy had a pigmented macule at the inoculation site. Rubella reinfection was uncommon, occurring at most in three of our subjects. All of the 186 susceptible children seroconverted, and 182 had hemagglutination-inhibiting (HI) titers of 8 or greater at four-year follow-up (geometric mean titer, 30.3). In the four children whose HI titers declined to undetectable levels, both HI and neutralizing (Nt) antibodies had developed immediately postimmunization, and two had Nt titers at follow-up despite loss of HI antibodies. RA27/3 vaccine boosted HI titers in 15 seropositive subjects, but titers returned to preimmunization levels four years later. We concluded that RA27/3 vaccine produced durable immunity with very low rates of rubella reinfection and secondary vaccine failure during the four years since immunization.