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Vaccine. 2013 Oct 1;31(42):4765-74. doi: 10.1016/j.vaccine.2013.08.009. Epub 2013 Aug 16.

Immune response to 13-valent pneumococcal conjugate vaccine with a reduced dosing schedule.

Author information

1
Pfizer Inc, Collegeville, PA, USA. Electronic address: gail.l.rodgers@gmail.com.

Abstract

BACKGROUND:

The 7-valent pneumococcal conjugate vaccine (PCV7) has demonstrated effectiveness against pneumococcal illnesses when administered as 3 infant doses plus a toddler dose (3+1 schedule) or as an abbreviated schedule of 2 infant doses plus a toddler dose (2+1 schedule). The 13-valent pneumococcal conjugate vaccine (PCV13) is approved and World Health Organization-prequalified for administration in a 2+1 schedule when used as part of routine immunization programs.

OBJECTIVE:

To summarize immunologic responses elicited by PCV13 administered in a 2+1 schedule and following 2 doses in a 3+1 schedule.

METHODS:

Studies were double-blind, randomized, active-controlled, multicenter studies except the Mexico study (open-label, single-arm). In 2+1 studies, PCV13 was administered at 2, 4, and 12 (UK) or 3, 5, and 11 (Italy) months. In 3+1 studies (Spain and Mexico), assessment was made postdose 2 of the primary series (2, 4, and 6 months). The primary immunogenicity endpoint was the proportion of participants achieving serotype-specific antipolysaccharide immunoglobulin (Ig)G concentrations ≥ 0.35μg/mL (i.e., responders) 1 month postdose 2. Pneumococcal IgG geometric mean concentrations (GMCs), opsonophagocytic activity (OPA), and concomitant vaccine responses were assessed.

RESULTS:

PCV13 and PCV7 elicited comparable immune responses for the 7 common serotypes after 2 infant doses. The proportion of PCV13 responders postdose 2 was >85% for most of the 7 common and 6 additional serotypes, except common serotypes 6B (27.9-81.4%) and 23F (55.8-77.5%) and additional serotypes 3 (73.8-96.9%) and 6A (79.2-94.4%). Serotypes 6B and 23F elicited lower IgG GMCs postdose 2 compared with other serotypes; all serotypes demonstrated boosting posttoddler dose. All serotypes demonstrated functional activity; >95% of participants achieved OPA levels ≥ 1:8 postdose 2. Concomitant vaccine responses were similar between PCV13 and PCV7 groups.

CONCLUSION:

Immune responses elicited by PCV13 following 2 infant doses support transition from PCV7 to PCV13 in countries using a 2+1 schedule.

TRIAL REGISTRATION:

ClinicalTrials.gov NCT00366899 NCT00368966 NCT00384059 NCT00474539 NCT00708682.

KEYWORDS:

2+1; Immune response; PCV13; Pediatric; Pneumococcal conjugate vaccine

PMID:
23965217
DOI:
10.1016/j.vaccine.2013.08.009
[Indexed for MEDLINE]

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