RESUMO
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.
Assuntos
Vacinas Pneumocócicas/administração & dosagem , Vacinas Pneumocócicas/imunologia , Vacinação/métodos , Anticorpos Antibacterianos/sangue , Método Duplo-Cego , Feminino , Humanos , Imunoglobulina G/sangue , Lactente , Itália , Masculino , México , Infecções Pneumocócicas/prevenção & controle , Espanha , Reino UnidoRESUMO
We evaluated the immunogenicity and safety of an investigational combination of 9-valent pneumococcal conjugate vaccine (PCV9) and meningococcal group C conjugate (MnCC) vaccine (PCV9-MnCC) administered concomitantly with Haemophilus influenzae type b (Hib) conjugate vaccine, and of a combination of the three vaccines mixed together as a single injection (Hib-PCV9-MnCC), and compared them to separately administered PCV9 and MnCC dispensed to Chilean infants at 2, 4, and 6 months of age. The frequency of adverse events was similar among groups. Recipients of PCV9 alone or in combination with the other vaccines mounted significant antibody responses to the nine pneumococcal serotypes in PCV9, with >88% achieving protective levels of > or =0.35microg/mL. For serotypes 6B, 9V, and 5, recipients of PCV9 alone had significantly higher geometric mean concentrations (GMCs) than those of the other vaccine groups. Similarly, the GMC of anti-PRP antibodies was significantly lower among recipients of Hib-PCV9-MnCC than among those who received Hib vaccine separately from PCV9 or MnCC. In Chilean infants, PCV9, PCV9-MnCC, and Hib-PCV9-MnCC were highly immunogenic and safe. Overall, interactions of PCV9, MnCC and Hib affected the magnitude (GMC) of the primary antibody responses to some of the antigens, but not the percentage of subjects who achieved protective antibody thresholds.