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SYSTEMATIC REVIEW ON THE EFFECTS OF DIFFERENT PNEUMOCOCCAL CONJUGATE VACCINE DOSING SCHEDULES ON IMMUNOGENICITY
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| Speaker: |
Daniel Park
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| Author: |
D.E. Park1, M.D. Knoll1, T.S. Johnson1, S. Chandir1, B.A.S. Nonyane1, D. Goldblatt2, L. Conklin3, K. Fleming-Dutra3,4, J. Loo3, C.G. Whitney3, K.L. O'Brien1
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| Affiliation: |
1International Vaccine Access Center, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA, 2Immunobiology Unit, UCL Institute of Child Health, London, UK, 3Division of Bacterial Diseases, National Center for Immunization and Respiratory Diseases, 4Epidemic Intelligence Service, Centers for Disease Control and Prevention, Atlanta, GA, USA
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Background: Despite the breadth of studies demonstrating benefits of pneumococcal conjugate vaccine (PCV), uncertainty remains regarding the optimal PCV dosing schedule in children.
Methods: We conducted a literature review of PCV immunogenicity published from 1994-2011. Studies included for analysis evaluated =2 doses of 7-valent or higher product (excluding Aventis-Pasteur PCV11) administered to non-high risk children =6 months of age. Impact of PCV schedule on antibody concentration (GMC) 1 month post-dose against 6 serotypes was assessed using random effects linear regression, adjusted for product, DTaP/DTwP co-administration, lab method, age at first dose, and geographic region.
Results: We evaluated 23 2-primary-dose, 87 3-primary-dose, 13 “2+1” (i.e., 2-primary plus boost), and 46 “3+1” schedules. GMC was higher following 3-primary compared to 2-primary doses for all serotypes except serotype 1. GMC was significantly higher for all serotypes when dose3 was administered in the second year compared to =6 months of age.
Conclusions: While giving the third dose in the second year of life produces higher antibodies than if given in the first 6 months, the lower GMC between the primary series and booster may increase an individual's risk of disease in that interval. In populations with high PCV coverage in infancy, this risk may be offset by indirect effects. Whether theoretical advantages of higher antibodies induced by giving the third dose in the second year of life, such as potential improvement for serotype 1 disease, longer duration of protection, or more rapid induction of herd effects, occur in practice needs to be evaluated.
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