The impact of pneumococcal vaccination and nasopharyngeal colonization on the performance of a serotype-specific urine antigen detection (SSUAD) assay.

Abstract

To better inform pneumococcal immunization policies, ongoing surveillance for pneumococcal community-acquired pneumonia (CAP) is crucial. To estimate the serotype-specific CAP burden of pneumococcal disease following the introduction of a new 15-valent pneumococcal conjugate vaccine (PCV), V114, a 15-plex serotype-specific urine antigen detection (SSUAD) assay was developed as a tool for surveillance of Streptococcuspneumoniae serotypes. V114-017 (NCT03547167; EudraCT 2017-004915-38) was a phase 3 randomized controlled trial in which participants (18-49 years) received V114 or 13-valent PCV (PCV13; as an active comparator), followed 6 months later by 23-valent pneumococcal polysaccharide vaccine (PPSV23). Here, we report findings from a prespecified sub-study nested within the phase 3 trial that descriptively assessed the impact of nasopharyngeal/oropharyngeal (NP/OP) carriage and pneumococcal vaccination on serotype detection with the SSUAD assay. In total, 301 individuals (all American Indian/Alaska Native) participated in the sub-study. NP/OP and urine samples were collected at 10 timepoints between baseline (prior to vaccination) and Month 7 (30 days following vaccination with PPSV23). NP/OP carriage was determined using qualitative polymerase chain reaction for pneumococcus detection and serotyping, and urine samples were tested in parallel with SSUAD. At any timepoint, NP/OP carriage was <2.0 % for 10 of the V114 serotypes; carriage was ∼2.6 % for serotype 1 and ranged between 4.0 % and 7.0 % for serotypes 4, 5, 9V, and 33F. At baseline, serotype-specific pneumococcal polysaccharide antigens were detected by SSUAD in only six study participants for serotypes 19A, 19F, and 1. SSUAD positivity for serotypes 4, 5, and 9V increased transiently following vaccination with V114/PCV13 and PPSV23, while SSUAD positivity lasted the longest for serotype 19A following PPSV23 vaccination. In general, SSUAD positivity appeared unrelated to NP/OP carriage. Our findings suggest SSUAD can support pneumococcal disease surveillance and vaccine effectiveness research, excluding individuals with recent pneumococcal vaccination to avoid false-positives.