Modeling of nasopharyngeal acquisition as a function of anti-capsular serum antibody concentrations and of ethnicity after vaccination with pneumococcal conjugate vaccines (PCVs)
large 13- and 7-valent PCV study in Israel provided sufficient nasopharyngeal
(NP-) acquisition and immunogenicity data for the 7 common serotypes (4, 6B,
9V, 14, 18C, 19F, 23F) and PCV7 cross-reacting serotype 6A (which is in PCV13)
to further investigate the reported correlation between NP-acquisition and
serum IgG levels, and the impact of ethnicity.
Methods: Anticapsular IgG concentrations measured one month after 3 PCV7/PCV13 doses (age = 7 months); and NP-acquisition collected at ages 7, 12, 13, 18 and 24 months enabled serotype specific analyses of 1410–1530 subjects. A logistic regression model assessed the rate of new acquisitions as a function of the logarithm of IgG concentrations, and was then adjusted by ethnicity.
Results: New NP-acquisition rates decreased as IgG concentrations increased for all studied serotypes (p<0.001 for 6A, 14, 23F; p=0.010 for 6B; p=0.089 for 19F; Figure 1). There were significant differences in the model between Bedouin and Jewish populations for all serotypes (covariate p-value, ≤0.007) except for serotype 4, where acquisition was low (9/1530). Despite higher acquisition rates in Bedouin children than in Jewish children, serotype-specific immune responses were similar across ethnic groups. Decrease in rates of NP-acquisition by increasing IgG concentrations within each ethnic group, seemed similar across the groups for most serotypes (Figure 2).
Conclusion: NP-acquisition decreased with increasing anti-capsular serum IgG for all common serotypes and serotype 6A. Despite different NP-acquisition rates observed between the ethnic groups, the dynamics of NP-acquisition reduction by increasing IgG concentrations were similar in the majority of serotypes studied, and seemed similar across ethnic groups.
Pfizer: Consultant and Speaker's Bureau, Grant recipient
MSD: Consultant, Grant recipient
GSK: Consultant and Speaker's Bureau, Speaker honorarium
J. Trammel, inVentiv Health Clinical: employee of CRO contracted by Pfizer to perform the analyses for this study, Salary
S. D. Patterson, Pfizer Vaccines Clinical Research: Employee, Salary
D. Greenberg, None
N. Givon-Lavi, None
N. Porat, None
W. C. Gruber, Pfizer: Employee and Shareholder, Salary
D. A. Scott, Pfizer: Employee and Shareholder, Salary