Persistence of immunity following 2-dose priming with a 10-valent pneumococcal conjugate vaccine at 6 and 10 weeks or 6 and 14 weeks of age in Nepalese toddlers

Journal article

Background:

The pneumococcal conjugate vaccine has had a substantial impact on invasive pneumococcal disease. Previously, we compared immunity following vaccination with the 10-valent pneumococcal conjugate vaccine (PCV10) administered at 2 slightly different schedules: at 6 and 10 weeks of age, and at 6 and 14 weeks of age, both followed by a 9-month booster. In this study, we followed up those participants to evaluate the medium-term persistence of serotype-specific pneumococcal immunity at 2-3 years of age.

Method:

Children from the previous studies were contacted and after taking informed consent from their parents, blood samples and nasopharyngeal swabs were collected. Serotype-specific IgG antibody concentrations were determined by enzyme-linked immunosorbent assay, for the 10 vaccine serotypes, at a WHO pneumococcal serology reference laboratory.

Findings:

Two hundred twenty of the 287 children who completed the primary study returned at 2–3 years of age to provide a blood sample and nasopharyngeal swab. The nasopharyngeal carriage rate of PCV10 serotypes in the 6 + 14 group was higher than the 6 + 10 group (13.4% vs. 1.9%). Nevertheless, the proportion of toddlers with serum pneumococcal serotype-specific IgG greater than or equal to 0.35 µg/mL was comparable for all PCV10 serotypes between the 6 + 10 week and 6 + 14 week groups. Similarly, the geometric mean concentrations of serum pneumococcal serotype-specific IgG levels were similar in the 2 groups for all serotypes, except for serotype 19F which was 32% lower in the 6 + 10 group than the 6 + 14 group.

Conclusion:

Immunization with PCV10 at 6 + 10 weeks or 6 + 14 weeks, with a booster at 9 months in each case, results in similar persistence of serotype-specific antibody at 2-3 years of age. Thus, protection from pneumococcal disease is expected to be similar when either schedule is used.

Authors: Gurung, M; Bijukchhe, SM; Hariri, P; Voysey, M; Kandasamy, R

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Lippincott, Williams & Wilkins
• Journal: Pediatric Infectious Disease Journal More from this journal
• Volume: 40
• Issue: 10
• Pages: 937-943
• Publication date: 2021-07-20
• Acceptance date: 2021-04-30
• DOI: 10.1097/inf.0000000000003223
• EISSN: 1532-0987
• ISSN: 0891-3668
• Pmid: 34292271
• Language: English
• Keywords: immunogenicity; Nepal; FFR; pneumococcal; pneumococcal conjugate vaccine; toddlers