Predictors of serological non-response to the 13-valent pneumococcal conjugate vaccine followed by the 23-valent polysaccharide vaccine among adults living with HIV

Background: People living with HIV (PLWH) have higher incidence of pneumococcal disease compared to people without HIV. Immunization with pneumococcal vaccines is recommended, but serological nonresponse to pneumococcal vaccination is common for largely unknown reasons. Methods: PLWH on antiretroviral treatment and no prior pneumococcal vaccination received the 13valent pneumococcal conjugate vaccine (PCV13) followed 60 days later by the 23-valent polysaccharide vaccine (PPV23). Serological response was evaluated 30 days post-PPV23 by antibodies against 12 serotypes covered by both PCV13 and PPV23. Seroprotection was defined as a >2-fold rise to a level above 1.3 lg/ml in geometric mean concentration (GMC) across all serotypes. Associations with nonresponsiveness were evaluated by logistic regression. Results: Fifty-two virologically suppressed PLWH (median age of 50 years (IQR 44-55) and median CD4 count of 634 cells/mm3 (IQR 507-792)) were included. Forty-six percent (95 % CI 32-61, n = 24) achieved seroprotection. Serotypes 14, 18C and 19F had the highest, and serotypes 3, 4 and 6B the lowest GMCs. Pre-vaccination GMC levels less than 100 ng/ml were associated with increased odds of nonresponsiveness compared to levels above 100 ng/ml (adjusted OR 8.7, 95 % CI 1.2-63.6, p = 0.0438). Conclusion: Less than half of our study population achieved anti-pneumococcal seroprotective levels following PCV13 and PPV23 immunization. Low pre-vaccination GMC levels were associated with nonresponse. Further research is required to optimize vaccination strategies that achieve higher seroprotection in this high-risk group. & COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).