Related Experiment Video
Updated: May 2, 2026
Experimental Human Pneumococcal Carriage
Published on: February 15, 2013
Pneumococcal serotype-specific antibodies persist through early childhood after infant immunization: follow-up from a
Johannes Trück1, Matthew D Snape1, Florencia Tatangeli1
1Oxford Vaccine Group, Department of Paediatrics, University of Oxford and the NIHR Oxford Biomedical Research Centre, Oxford, United Kingdom.
Insights
Pneumococcal conjugate vaccines (PCV-7 and PCV-13) given in infancy provide sustained protection against common serotypes up to preschool age. A PCV-13 booster at preschool age further enhances immunity with minimal adverse effects.
Area of Science:
- Pediatric immunology
- Vaccinology
- Infectious disease prevention
Background:
- Previous UK study administered 7-valent (PCV-7) or 13-valent (PCV-13) pneumococcal conjugate vaccines to infants at 2, 4, and 12 months.
- At 13 months, most children exhibited protective pneumococcal serotype-specific IgG concentrations and opsonophagocytic assay (OPA) titers.
Purpose of the Study:
- To assess the persistence of immunity following infant pneumococcal conjugate vaccination (PCV-7 or PCV-13).
- To evaluate the immune response to a PCV-13 booster dose at preschool age (3.5 years).
Main Methods:
- 108 children from the original cohort were re-enrolled at 3.5 years of age.
- Children received a PCV-13 booster dose.
- Serotype-specific IgG concentrations and OPA titers were measured to assess immune persistence and response.
Main Results:
- At 3.5 years, a majority of children retained protective IgG levels against most vaccine serotypes, with higher persistence in the PCV-13 group for some serotypes.
- Immunity against pneumococcal serotypes 4 and 18C showed lower persistence (22-42%).
- The PCV-13 booster was highly immunogenic, eliciting robust antibody responses with low rates of local and systemic adverse effects.
Conclusions:
- Infant pneumococcal conjugate vaccination confers significant, albeit partially waning, protection into preschool years.
- A PCV-13 booster dose at preschool age is effective in restoring and enhancing immunity against pneumococcal serotypes.
- These findings support continued use of pneumococcal conjugate vaccines for sustained protection in children.
Background:
In a previous UK multi-center randomized study 278 children received three doses of 7-valent (PCV-7) or 13-valent (PCV-13) pneumococcal conjugate vaccine at 2, 4 and 12 months of age. At 13 months of age, most of these children had pneumococcal serotype-specific IgG concentrations ≥ 0.35 µg/ml and opsonophagocytic assay (OPA) titers ≥ 8.
Methods:
Children who had participated in the original study were enrolled again at 3.5 years of age. Persistence of immunity following infant immunization with either PCV-7 or PCV-13 and the immune response to a PCV-13 booster at pre-school age were investigated.
Results:
In total, 108 children were followed-up to the age of 3.5 years and received a PCV-13 booster at this age. At least 76% of children who received PCV-7 or PCV-13 in infancy retained serotype-specific IgG concentrations ≥ 0.35 µg/ml against each of 5/7 shared serotypes. For serotypes 4 and 18C, persistence was lower at 22-42%. At least 71% of PCV-13 group participants had IgG concentrations ≥ 0.35 µg/ml against each of 4/6 of the additional PCV-13 serotypes; for serotypes 1 and 3 this proportion was 45% and 52%. In the PCV-7 group these percentages were significantly lower for serotypes 1, 5 and 7F. A pre-school PCV-13 booster was highly immunogenic and resulted in low rates of local and systemic adverse effects.
Conclusion:
Despite some decline in antibody from 13 months of age, these data suggest that a majority of pre-school children maintain protective serotype-specific antibody concentrations following conjugate vaccination at 2, 4 and 12 months of age.
Trial Registration:
ClinicalTrials.gov NCT01095471.
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