Related Experiment Videos
Polio immunity to killed vaccine: an 18-year follow-up
1National Bacteriological Laboratory, Stockholm, Sweden.
Insights
Long-term polio vaccination in children shows sustained antibody levels. A later booster dose at age ten resulted in significantly higher antibody levels by age 18 compared to an earlier dose at age six.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Killed polio vaccine (IPV) was administered to children in Sweden starting in 1967.
- Longitudinal studies are crucial for understanding the durability of vaccine-induced immunity.
Purpose of the Study:
- To assess the long-term neutralizing antibody levels against poliovirus in children vaccinated with IPV.
- To evaluate the impact of booster dose timing on sustained antibody responses.
Main Methods:
- A cohort of 250 children vaccinated with IPV in 1967 was followed for 18 years.
- Neutralizing antibody titers against poliovirus were measured periodically.
- Antibody levels were compared between children receiving a fourth booster dose at age 6 versus age 10.
Main Results:
- All participants had detectable poliovirus antibodies at age 18.
- Antibody titers showed an initial decline followed by stabilization (0.05-0.10 log10 per year).
- Children receiving the booster at age 10 exhibited significantly higher antibody levels at age 18 than those boosted at age 6.
Conclusions:
- IPV vaccination provides long-lasting antibody protection against poliovirus.
- Postponing the fourth booster dose to age 10 enhances sustained antibody levels into late adolescence.
Abstract:
Two hundred and fifty children born in 1967 and vaccinated with killed polio vaccine in Sweden were followed for 18 years and tested for neutralizing antibodies against polio. All of them had demonstrable antibodies at the age of 18. Sixty-four children were tested in samples collected throughout the years. After a more marked fall of antibody titres during the first few years after vaccination, the decline levelled off to a mean decrease in titre of 0.05-0.10 log10 per year. In half of them, the routine vaccination comprising a fourth dose at 6 years of age was changed and this booster was postponed to the age of ten. The children given the booster dose at ten had significantly higher antibody levels at 18 years of age than those given it at six.