Post-Marketing Surveillance of Adverse Events Following 23-Valent Pneumococcal Polysaccharide Vaccination - China, 2021-2024.

Introduction: This study assesses the adverse events following vaccination with the 23-valent pneumococcal polysaccharide vaccine (PPV23) in China from 2021 to 2024. Methods: We obtained reports of adverse events following immunization (AEFI) with PPV23 and the number of PPV23 doses administered during the study period from the Chinese National Immunization Information System (CNIIS). We descriptively analyzed the AEFI characteristics and reported incidences per 100,000 doses administered. Results: During the study period, 26.65 million doses of PPV23 were administered and 22,221 PPV23 AEFI were reported, i.e., a reported incidence of 83.37 AEFI per 100,000 doses administered. The incidence per 100,000 doses of common vaccine reactions was 80.51, and the incidences of rare vaccine reactions and serious AEFI were 1.70 and 0.43, respectively. The incidences of AEFI, common vaccine reactions, and rare vaccine reactions decreased with age. The most frequently reported common vaccine reactions were fever (54.07/100,000 doses) and local redness and swelling (41.61/100,000 doses), and the most frequent rare vaccine reaction was allergic rash (0.92/100,000 doses). 99.15% of adverse vaccine reactions occurred within 3 days after vaccination. Conclusion: PPV23 had a good safety profile during 2021 to 2024. The findings support the use of PPV23 as recommended from a safety perspective.