Evaluation of the epidemiological efficacy of 23-valent pneumococcal polysaccharide vaccine among the elderly in Minhang District of Shanghai
Objective 
To evaluate the epidemiological efficacy of 23-valent pneumococcal polysaccharide vaccine on the clinical symptoms and the incidence of respiratory tract infections in the elderly over 60 years old in Minhang District, Shanghai. 
 
 
Methods 
A prospective cohort study was conduct, in which the sample size was 1 200 for both inoculated and uninoculated groups. This study followed the two groups of subjects every quarter for a year. Clinical symptoms and the incidence of respiratory tract infectious diseases as well as the acute onset of chronic respiratory diseases were compared between the subjects of the two groups. 
 
 
Results 
Compared with the uninoculated group, less people in the inoculated group developed the clinical symptoms of respiratory tract infection (RR=0.894, 95% CI: 0.804-0.994). Immunization with the 23-valent pneumococcal polysaccharide vaccine protected 57.7% of the senior citizens (≥75 years old) from respiratory tract infections(95% CI: 0.207-0.775). 
 
 
Conclusion 
The 23-valent pneumococcal polysaccharide vaccine can effectively reduce the incidence of respiratory tract infections in the elderly aged 60 years old and over and protects the elderly aged 75 years old and over from respiratory tract infections. Further studies on the immunological efficacy of 23-valent pneumococcal polysaccharide vaccine should be carried out by measuring the antibody titers before and after vaccination. 
 
 
Key words: 
The elderly; Pneumococcal vaccine; Respiratory tract infection; Cohort study; Efficacy evaluation