Effect of pneumococcal conjugate vaccine six years post-introduction on pneumococcal carriage in Ulaanbaatar, Mongolia

• Published in: Nature communications Vol. 15; no. 1; pp. 6577 - 11
• Main Authors: von Mollendorf, Claire, Mungun, Tuya, Ulziibayar, Munkhchuluun, Skoko, Paige, Boelsen, Laura, Nguyen, Cattram, Batsaikhan, Purevsuren, Suuri, Bujinlkham, Luvsantseren, Dashtseren, Narangerel, Dorj, Tsolmon, Bilegtsaikhan, Demberelsuren, Sodbayar, Ortika, Belinda D., Pell, Casey L., Wee-Hee, Ashleigh, Nation, Monica L., Hinds, Jason, Dunne, Eileen M., Mulholland, E. Kim, Satzke, Catherine
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 03.08.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 45; 45/22; 45/61; 631/326/590; 692/308/3187; 692/699/255/1318; Antimicrobial resistance; Carrier State - epidemiology; Carrier State - microbiology; Carrier State - prevention & control; Conjugates; Cross-Sectional Studies; Density; DNA chips; DNA microarrays; Female; Humanities and Social Sciences; Humans; Infant; Long-term effects; Male; Mongolia - epidemiology; multidisciplinary; Nasopharynx - microbiology; Nucleotide sequence; Pneumococcal Infections - epidemiology; Pneumococcal Infections - immunology; Pneumococcal Infections - microbiology; Pneumococcal Infections - prevention & control; Pneumococcal Vaccines - administration & dosage; Pneumococcal Vaccines - immunology; Prevalence; Real time; Science; Science (multidisciplinary); Serogroup; Serotyping; Streptococcus pneumoniae - classification; Streptococcus pneumoniae - genetics; Streptococcus pneumoniae - immunology; Streptococcus pneumoniae - isolation & purification; Surveys; Vaccine development; Vaccines; Vaccines, Conjugate - immunology; Mongolia
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-50944-3

Limited data from Asia are available on long-term effects of pneumococcal conjugate vaccine introduction on pneumococcal carriage. Here we assess the impact of 13-valent pneumococcal conjugate vaccine (PCV13) introduction on nasopharyngeal pneumococcal carriage prevalence, density and antimicrobial resistance. Cross-sectional carriage surveys were conducted pre-PCV13 (2015) and post-PCV13 introduction (2017 and 2022). Pneumococci were detected and quantified by real-time PCR from nasopharyngeal swabs. DNA microarray was used for molecular serotyping and to infer genetic lineage (Global Pneumococcal Sequence Cluster). The study included 1461 infants (5–8 weeks old) and 1489 toddlers (12–23 months old) enrolled from family health clinics. We show a reduction in PCV13 serotype carriage (with non-PCV13 serotype replacement) and a reduction in the proportion of samples containing resistance genes in toddlers six years post-PCV13 introduction. We observed an increase in pneumococcal nasopharyngeal density. Serotype 15 A, the most prevalent non-vaccine-serotype in 2022, was comprised predominantly of GPSC904;9. Reductions in PCV13 serotype carriage will likely result in pneumococcal disease reduction. It is important for ongoing surveillance to monitor serotype changes to potentially inform new vaccine development. Pneumococcal carriage is a useful outcome to evaluate pneumococcal conjugate vaccine (PCV) introduction. Here the authors conducted cross-sectional carriage surveys before (2015) and after 13-valent PCV introduction (2017 and 2022) in Mongolia to determine vaccine impact.