Abstract： Objective To evaluate safety and immunogenicity of one dose of 23-valent pneumococcal polysaccharide vaccine(PPV23)in a healthy population aged ≥2 years.Methods We recruited healthy subjects aged 2-5,6-15,16-59,and ≥60 years into an open-label phase Ⅳ clinical trial and observed for adverse events 0-30 days after one dose of PPV23 vaccination to determine incidence of adverse events.We tested serum samples for IgG antibodies against each of 23 Streptococcus pneumoniae(Spn)serotypes before and 30 days after vaccination to determine seroconversion rates,geometric mean concentrations(GMC),and geometric mean increases(GMI).Results Among the 2 997 subjects who received one dose of PPV23,the overall incidence of vaccine-related adverse events was 10.84％(325 cases).Incidences for grade 1,2,3,and 4 adverse events were 9.94％,0.77％,0.13％,and 0.00％;and for injection-site pain and fever were 4.50％and 1.40％.Among 273 subjects,seroconversion rates,GMCs,and GMIs of IgG antibodies against 23 Spn serotypes after vaccination ranged from 92.83％to 99.66％,from 2.00 to 63.34 μg/mL,and from 6.82 to 171.24.Conclusions One dose of PPV23 showed good safety and immunogenicity profiles among healthy individuals ≥2 years of age.