Unmasking Pneumococcal Carriage in a High Human Immunodeficiency Virus (HIV) Prevalence Population in two Community Cohorts in South Africa, 2016-2018: The PHIRST Study.

Background: Longitudinal pneumococcus colonization data in high human immunodeficiency virus (HIV) prevalence settings following pneumococcal conjugate vaccine introduction are limited.
Methods: In 327 randomly selected households, 1684 individuals were enrolled and followed-up for 6 to 10 months during 2016 through 2018 from 2 communities. Nasopharyngeal swabs were collected twice weekly and tested for pneumococcus using quantitative lytA real-time polymerase chain reaction. A Markov model was fitted to the data to define the start and end of an episode of colonization. We assessed factors associated with colonization using logistic regression.
Results: During the study period, 98% (1655/1684) of participants were colonized with pneumococcus at least once. Younger age (<5 years: adjusted odds ratio [aOR], 14.1; 95% confidence [CI], 1.8-111.3, and 5-24 years: aOR, 4.8, 95% CI, 1.9-11.9, compared with 25-44 years) and HIV infection (aOR, 10.1; 95% CI, 1.3-77.1) were associated with increased odds of colonization. Children aged <5 years had fewer colonization episodes (median, 9) than individuals ≥5 years (median, 18; P < .001) but had a longer episode duration (<5 years: 35.5 days; interquartile range, 17-88) vs. ≥5 years: 5.5 days (4-12). High pneumococcal loads were associated with age (<1 year: aOR 25.4; 95% CI, 7.4-87.6; 1-4 years: aOR 13.5, 95% CI 8.3-22.9; 5-14 years: aOR 3.1, 95% CI, 2.1-4.4 vs. 45-65 year old patients) and HIV infection (aOR 1.7; 95% CI 1.2-2.4).
Conclusions: We observed high levels of pneumococcus colonization across all age groups. Children and people with HIV were more likely to be colonized and had higher pneumococcal loads. Carriage duration decreased with age highlighting that children remain important in pneumococcal transmission.
Competing Interests: Potential conflicts of interest. M. C. has received the Robert Austrian Award sponsored by Pfizer as well as received funding as part of the South Africa-Pittsburgh Public Health Genomic Epidemiology (SAPPHGenE) training program and reports support for attending meetings and/or travel paid to the institution from Bill and Melinda Gates Foundation. D. T. received funding from the UK National Institute of Health Research Mucosal Pathogen Research 336 Unit (NIHR-MPRU) at University College London. C. C. has received grant support from Sanofi Pasteur, Advanced Vaccine Initiative, CDC, Wellcome Trust, PATH, Bill and Melinda Gates Foundation, and South African Medical Research Council (SA-MRC). A. v. G. has received grant support from Sanofi Pasteur, Pfizer related to pneumococcal vaccine, CDC, and the Bill and Melinda Gates Foundation and reports being chairperson at their local NiTAG. N. W. report grants from Sanofi Pasteur and the Bill and Melinda Gates Foundation paid to the institution. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
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