deusthindwa/markov.model.pneumococcus.hiv.malawi

doi.org # Estimating pneumococcal carriage dynamics in adults living with HIV in a mature infant pneumococcal conjugate vaccine program in Malawi, a modelling study Background: Adults living with human immunodeficiency virus (ALWHIV) taking antiretrovirals (ART) have higher pneumococcal carriage and disease than adults without HIV (HIV-). To assess factors influencing the high carriage prevalence and generate evidence base for evaluating future pneumococcal conjugate vaccine (PCV) strategies in ALWHIV, we estimated carriage acquisition and clearance rates in a high transmission and disease-burdened setting. Methods: We collected longitudinal nasopharyngeal swabs from age-and sex-matched HIV- adults, ALWHIV with ART experience of more than 1 year (ART>1y) or less than 3 months (ART 1 child U5, and 41.6% lived in low SES. Median age was 33y (interquartile range [IQR]: 25-37). Baseline pneumococcal carriage prevalence of non-PCV13 serotypes (NVT) (26.2%) was higher than PCV13 serotypes (VT) (5.1%). In a multivariate longitudinal analysis, pneumococcal carriage acquisition was higher in females than males (NVT [Hazard Ratio [HR]: 1.53, 95%CI:1.17-2.01]; VT [1.96, 1.11-3.49]). It was also higher in low than high SES (NVT [1.38, 1.03-1.83]; VT [2.06, 1.13-3.77]), in adults living with 2+ than 1 child U5 (VT [1.78, 1.05-3.01]), and in ALWHIV on ART>1y than HIV- adults (NVT [1.43, 1.01-2.02]. Moreover, ALWHIV on ART>1y cleared pneumococci slower than HIV- adults ([0.65, 0.47-0.90]). Residual VT 19F and 3 were highly acquired although NVT remained dominant. Conclusions: The disproportionately high point prevalence of pneumococcal carriage in ALWHIV on ART>1y is likely due to impaired nasopharyngeal clearance resulting in prolonged carriage. Our findings provide baseline estimates for comparison after new PCV strategies in ALWHIV are implemented. Key words: Pneumococcal acquisition, Pneumococcal duration, Serotype, Human immunodeficiency virus, Modelling, Malawi