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Age- and dose-interval-dependent antibody responses to inactivated poliovirus vaccine
H Sormunen1, M Stenvik, J Eskola
1Department of Virology, National Public Health Institute (KTL), Helsinki, Finland.
Insights
Different inactivated poliovirus vaccine (IPV) schedules impact antibody responses in children. Optimal antibody persistence was observed with a later third dose and avoiding early initial doses or short intervals.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Inactivated poliovirus vaccine (IPV) is crucial for polio eradication.
- Understanding optimal IPV immunization schedules is vital for robust and lasting immunity in children.
Purpose of the Study:
- To evaluate the impact of varying three-dose inactivated poliovirus vaccine (IPV) schedules on antibody responses in children.
- To determine the influence of age at first dose, interval between doses, and timing of the third dose on antibody persistence.
Main Methods:
- Five groups of children received three doses of IPV according to different schedules.
- Antibody titers against poliovirus serotypes (PV1, PV2, PV3) were measured at various time points.
- Correlation between maternal antibody levels and infant antibody response was analyzed.
Main Results:
- Initial antibody responses were influenced by the age at the first dose and the interval between the first two doses in a serotype-dependent manner.
- While all schedules achieved sufficient antibody levels after three doses, a third dose at 18 months yielded higher persisting antibody levels than at 12 months.
- The current standard schedule (first dose at 6 months) resulted in the highest persisting antibody titers against PV1 and PV2 at 3 years.
- Maternal antibody levels at the time of the first dose negatively correlated with antibody titers at 3 years of age.
Conclusions:
- Multiple IPV schedules can induce satisfactory immune responses in children.
- For optimal and long-lasting antibody levels, initiating the IPV program very early and using short dosage intervals should be avoided.
- The timing of the third IPV dose and the initial vaccination schedule significantly affect long-term antibody persistence.
Abstract:
Antibody responses were studied in five groups of children immunized with different three-dose schedules of inactivated poliovirus vaccine (IPV). The age of the child at the first dose (1-4 months) and the interval between the first and second doses (2-4 months) influenced the initial responses in a serotype-dependent manner. All the groups attained sufficient antibody level after three doses but the third dose given at 18 months resulted in higher persisting antibody levels than that given at 12 months. The highest persisting antibody titers against PV1 and PV2 (but not against PV3) at the age of 3 years were measured in the control group immunized with the current schedule (P < 0.001) in which the first dose is given at 6 months. The level of maternal antibodies present at the time of the first dose correlated negatively with the antibody titers as late as at 3 years of age. It is concluded that three doses of IPV given in widely variable schedules may result in satisfactory immune responses in children but, for optimal results, very early onset of the program and short dosage intervals should be avoided.