Streptococcus pneumoniae Nasopharyngeal Carriage among PCV-10-Vaccinated HIV-1-Infected Children with Maintained Serological Memory in Ethiopia

Abstract

Streptococcus pneumoniae (S. pneumoniae) vaccines have substantially reduced the burden of invasive pneumococcal diseases (IPDs) worldwide. Despite high coverage with S. pneumoniae vaccination, upper-respiratory-tract colonization by S. pneumoniae is still common. We assessed maintenance of serological responses to S. pneumoniae serotypes included in PCV-10 by ELISA in HIV-1-infected children (n = 50) and age-matched controls (n = 50) in Ethiopia. We isolated S. pneumoniae in nasopharyngeal swabs and determined S. pneumoniae serotype by whole genome sequencing (WGS). Comparable levels of S. pneumoniae serotype-specific IgG concentrations were detected in plasma of HIV-1-infected children and matched controls, with geometric mean concentrations (GMCs) consistently higher than the protective threshold for PCV-10 serotypes of 0.35 μg/mL. We isolated S. pneumoniae from 38 (out of 97) nasopharyngeal swabs, 25 from HIV-1-infected children and 13 from controls. WGS based serotyping revealed 22 known S. pneumoniae serotypes and 2 nontypeable (NT) isolates. Non-PCV-10 serotypes represented >90% of isolates. We showed that HIV-1-infected children and matched controls in Ethiopia carry a level of maintained serological memory to PCV-10 considered protective for IPDs. We identified a higher proportion of nasopharyngeal carriage with highly pathogenic S. pneumoniae non-PCV strains among HIV-1-infected children compared to controls.

Nasopharyngeal Staphylococcus aureus colonization among HIV-infected children in Addis Ababa, Ethiopia: antimicrobial susceptibility pattern and association with Streptococcus pneumoniae colonization

“…The study by Mulu and colleagues from Northern Ethiopia reports pharyngeal carriage and samples might not have been taken from the nasopharynx. Our results were however lower than those reported from the same hospital as the current study at a later time point (2018–2019), 52 %(26/50) [30]. The differences in carriage prevalence might be due to differences in the median ages of the study populations, which was the 53.5 months' range (24–89) in the study by Lemma and colleagues while in the current study the median age is the 132 months' range (36–168).…”