Evaluating the effectiveness of pneumococcal conjugate vaccine in Taoyuan city on adult population

Abstract

Abstract Pneumococcus is one of the major threat for senior citizens health worldwide. Pneumococcal Conjugate Vaccines (PCV7, PCV10, and PCV13) were gradually commenced in the national pediatric immunization programme in Taiwan since 2005 and polysaccharide pneumococcal vaccine (PPV23) was granted adult indication since 2015. However, in a most-recent nationwide long-term surveillance, the PCV13 serotypes have shifted to being dominated types in that of > = 65 years-old seniors. This study aims to evaluate the PCV13-introduction effectiveness based on a selected test city. Data of the national health insurance research database (NHIRD) between 2013 and 2018 were retrieved to collect data on yearly medical use of citizen aged 65-66 years and were linked to the death registry database for death-ascertainment. Compared to females, males had more hospitalization due to IPD (RR = 1.37, 95% CI: 1.04-1.79) and due to pneumonia (1.69, 1.34-2.14). The introduction of PCV13 free-vaccination was associated with significant reductions of hospitalization by 40% for IPD (0.6, 0.51-0.71) and 36% for pneumonia (0.64, 0.58-0.7) in females. However, the effects were not significant in both sex combined and in males. As far as mortality is concerned, the introduction of the PCV13 free-vaccination had 33% lower risk of all cause death with IPD claimed within one month of death (0.67, 0.49-0.91) and for pneumonia (0.77, 0.60-0.99). This was also observed in both sex combined (0.82, 0.68-0.98) for IPD, but not for pneumonia, or for both events in males. In conclusion, the policy of PCV13 vaccination for seniors aged 65 years was associated with all-cause mortality with IPD or pneumonia claims one month before death. The evidence was stronger in females than in males. The effectiveness for the associated reduced hospitalization has been demonstrated in females. Further analysis with individual vaccination history and extended years is needed. Funding: The current study was funded by Pfizer Limited (Taiwan). Key messages The pneumococcal serotype shift has been found in elderly from PPV-23 vaccine-type to PCV vaccine-type and hence the preparedness of PCV13-introduction for elderly immunization programme is necessary. The findings of this pilot study included the effectiveness of PCV13-introduction in seniors aged 65 years and some implications to subgroup analyses needed for preparing a nationwide implementation.