2574. Serotype Distribution of Streptococcus pneumoniae and Pneumococcal Vaccine Coverage in Adults in Turkey between 2019 and 2022

BACKGROUND: Streptococcus pneumoniae infections are challenging due to pneumococci having more than 100 serotypes. This ongoing study is aimed to evaluate serotype distribution of S. pneumoniae causing pneumococcal infections in adults ( >18 years) and to provide a perspective regarding serotype coverage of both current and future pneumococcal vaccines. [Figure: see text] METHODS: Pneumococcal strains were collected from 22 centers between January 2019 and December 2022. Serogrouping was performed using latex particle agglutination, and serotyping was performed by the conventional Quellung reaction using commercial type-specific antisera (Statens Serum Institut, Copenhagen, Denmark). RESULTS: During the study period, 212 pneumococcal strains (156 males [73.6%] and 56 females [26.4%]) were collected from adults over 18 years of age. Of the isolates, 114 (53.8%) were from patients < 65 years old and 98 (46.2%) were from patients ≥65 years old. The majority of isolates were obtained from blood (n=123, 58%) followed by bronchoalveolar lavage [BAL] (n=38, 17.9%) and cerebrospinal fluid (CSF) (n=25, 11.7%). The most frequently isolated serotypes were 3, 9N and 8. The vaccine coverage for PCV13, PCV15, PCV20, and PPV23 was 36.3%, 36.7%, 50.9%, and 56. 1%, respectively, in all isolates. The vaccine serotype coverage rates in the study group are shown in Table-1. CONCLUSION: It has been observed in time that while vaccine serotypes are decreasing, serotypes not covered by vaccines are increasing. Accordingly, surveillance is essential to determine vaccination policy. DISCLOSURES: Mehmet Ceyhan, n/a, Pfizer Pharmaceuticals, Istanbul, Turkey: Advisor/Consultant|Pfizer Pharmaceuticals, Istanbul, Turkey: Grant/Research Support