Dual influenza and pneumococcal vaccination was associated with lower short-term risks of all-cause and acute respiratory hospitalizations among the elderly in Shenzhen, China: a retrospective cohort study

A narrative review on the effectiveness of PPSV23 vaccination in adults in China

Pneumococcal Polysaccharide Vaccine (PPSV23) is available for free in some Chinese cities for elderly patients and those with comorbidities. However, there is a lack of studies summarizing its preventive effect specifically in Chinese adults. This review aims to discuss the epidemiology of pneumococcal disease, coverage and effectiveness of PPSV23 vaccination, elderly individuals and patients with comorbidities, coadministration of PPSV23 vaccine with other vaccines, and future directions for its use in China. It was found that the PPSV23 vaccination rate among the elderly ranged from 1.2% to 42.1% depending on location, with an effectiveness of 9.34%(95%CI: 2.05%, 16.62%) to 57.7%(95%CI: 20.7%, 77.5%). There is a need to raise awareness of pneumococcal disease and its prevention, especially in China. To better manage pneumococcal disease in China, developing new vaccines for common serotypes and continuously monitoring serotype distribution associated with the disease is also needed.

Application of methodological strategies to address unmeasured confounding in real-world vaccine safety and effectiveness study: a systematic review

OBJECTIVES

Uses of real-world data to evaluate vaccine safety and effectiveness are often challenged by unmeasured confounding. The study aimed to review the application of methods to address unmeasured confounding in observational vaccine safety and effectiveness research.

STUDY DESIGN AND SETTING

We conducted a systematic review (PROSPERO: CRD42024519882), and searched PubMed, Web of Science, Embase, and Scopus for epidemiological studies investigating influenza and COVID-19 vaccines as exposures, and respiratory and cardiovascular diseases as outcomes, published between January 1, 2017, and December 31, 2023. Data on study design and statistical analyses were extracted from eligible articles.

RESULTS

A total of 913 studies were included, of which 42 (4.6%, 42/913) accounted for unmeasured confounding through statistical correction (31.0%, 13/42) or confounding detection or quantification (78.6%, 33/42). Negative control was employed in 24 (57.1%, 24/42) studies-2 (8.3%, 2/24) for confounding correction and 22 (91.7%, 22/24) for confounding detection or quantification-followed by E-value (31.0%, 13/42), prior event rate ratio (11.9%, 5/42), regression discontinuity design (7.1%, 3/42), instrumental variable (4.8%, 2/42), and difference-in-differences (2.4%, 1/42). A total of 871 (95.4%, 871/913) studies did not address unmeasured confounding, but 38.9% (355/913) reported it as study limitation.

CONCLUSION

Unmeasured confounding in real-world vaccine safety and effectiveness studies remains underexplored. Current research primarily employed confounding detection or quantification, notably negative control and E-value, which did not yield adjusted effect estimates. While some studies used correction methods like instrumental variable, regression discontinuity design, and negative control, challenges arise from the stringent assumptions. Future efforts should prioritize developing valid methodologies to mitigate unmeasured confounding.

Attitudes Toward General Vaccination Mediate the Association Between Influenza Vaccination History and Pneumococcal Vaccination Intention Among Older Adults in China

Background: Influenza and pneumococcal vaccinations play a crucial role in disease prevention among older adults and are recommended to older adults aged 60 years and over in China, but the vaccination rates are suboptimal. Behavioral spillover indicates that a change in one behavior may lead to changes in other related behaviors. Objective: Based on the Behavioral Spillover Theory, this study aimed to investigate the association between influenza vaccination history and pneumococcal vaccination intention, as well as the mediating role of negative attitudes toward general vaccination among older adults in China. Method: A multi-center cross-sectional survey was conducted among 1031 older adults, and 658 participants (median age: 65.0 ± 9.0 years) who had not received pneumococcal vaccination were included in the analysis. Correlation analysis and path analysis were performed. Results: A significant positive association was observed between influenza vaccination history and pneumococcal vaccination intention (r = 0.167, p < 0.001). In contrast, negative attitudes toward general vaccination, including mistrust of vaccine benefits (r = -0.253, p < 0.001), worries about unforeseen future effects (r = -0.180, p < 0.001), concerns about commercial profiteering (r = -0.360, p < 0.001), and a preference for natural immunity (r = -0.212, p < 0.001) were negatively associated with pneumococcal vaccination intention. Negative attitudes toward general vaccination mediated the association between influenza vaccination history and pneumococcal vaccination intention (total indirect effect = 0.119, p < 0.001, effect size = 50.0%). Conclusion: These findings demonstrated that influenza vaccination history may reduce negative attitudes toward general vaccination, which may further increase pneumococcal vaccination intention, indicating spillover effects of influenza vaccination history. To promote vaccination behavior among older adults, addressing negative attitudes toward general vaccination is crucial.

Optimization of Elderly Influenza and Pneumococcal Immunization Programs in Beijing, China Using Health Economic Evaluations: A Modeling Study

(1) Background: Currently, residents ≥ 60 and ≥65 years old in Beijing, China, are eligible for free influenza and pneumococcal polysaccharide vaccines (PPSV23), respectively. The present study aimed to assess the cost-effectiveness of current and alternative strategies of dual influenza and PPSV23 vaccination among the elderly in Beijing. (2) Methods: We developed a Markov state-transition model to compare the costs and the quality-adjusted life years (QALYs) associated with four influenza and PPSV23 vaccination strategies among the elderly in Beijing. The strategies were as follows: (1) no vaccination; (2) only flu vaccine for people ≥ 60 years old; (3) flu vaccine for people ≥ 60 years old and PPSV23 for people ≥ 65 years old; and (4) dual influenza vaccines and PPSV23 for people ≥ 60 years old. Incremental costs and QALYs were quantified to determine the optimal option. If dominant strategies emerged, the Chinese gross domestic product per capita in 2021 (80,976 CNY) was used as the willingness-to-pay (WTP) threshold to covert QALYs into the monetary equivalent. (3) Results: The current program saved costs and increased QALYs compared to no vaccination or flu vaccine-only strategies. However, extending free PPSV23 to people ≥ 60 years old saved 0.35 CNY additionally while increasing QALYs marginally compared with the current policy. Results were robust in all sensitivity analyses. (4) Conclusion: Beijing's current dual influenza and pneumococcal vaccination program was cost-effective among the elderly compared with the preceding policies of no vaccination and flu-only immunization programs. However, the program can further save money while enhancing the population health by extending PPSV23 to all people ≥ 60 years old.

Manifesto on the Value of Adult Immunization: "We Know, We Intend, We Advocate"

Immunization through vaccination is a milestone achievement that has made a tremendous contribution to public health. Historically, immunization programs aimed firstly to protect children, who were disproportionally affected by infectious diseases. However, vaccine-preventable diseases can have significant impacts on adult mortality, health, and quality of life. Despite this, adult vaccinations have historically been overlooked in favor of other health priorities, because their benefits to society were not well recognized. As the general population is aging, the issue of vaccination in older adults is gaining importance. In high-income countries, recommendations for the routine vaccination of older adults have been gradually introduced. The Italian National Immunization Plan is considered to be among the most advanced adult vaccination plans in Europe. However, available data indicate there is low adherence to vaccination recommendations in Italy. The COVID-19 pandemic has exposed the damage that can be caused by an infectious disease, especially among adults and individuals with comorbidities. The aim of this “Manifesto”, therefore, is to provide an overview of the existing evidence on the value of adult vaccination, in the Italian context, with a call to action to healthcare providers and health authorities.

Cost-effectiveness of dual influenza and pneumococcal vaccination among the elderly in Shenzhen, China

OBJECTIVE

To assess the cost-effectiveness of dual influenza and pneumococcal vaccination for the elderly in Shenzhen, China.

METHODS

A Markov state-transition model with a weekly cycle was developed to compare the outcomes of dual influenza and pneumococcal vaccination for the prevention of influenza and pneumococcal infections compared with no vaccination among 70-74 years old people in Shenzhen over 5 years. The model allowed seasonal variation of influenza activity. We calculated the incremental cost-effectiveness ratio (ICER) with costs and quality-adjusted life years (QALYs) discounted at 5% annually from the societal perspective. The impact of parameter uncertainty on the results was examined using one-way and probabilistic sensitivity analyses (PSA).

RESULTS

In the base case, dual vaccination prevented 5042 influenza infections, 26 IPD cases, 3 disabilities, 34 deaths, and cost US$7.1 per person while resulting in a net gain of 0.0026 QALYs compared with no vaccination. Using once the Chinese gross domestic product per capita in 2019 (US$10,289) as the willingness-to-pay threshold, dual vaccination was cost-effective with an ICER of US$2699 per QALY gained. One-way sensitivity analyses showed that the ICER was relatively sensitive to changes in influenza attack rates and influenza vaccine effectiveness. Based on the results of PSA with 1000 Monte Carlo simulations, receiving both vaccines was cost-effective in 100% of the repetitions.

CONCLUSION

The current study provides evidence that dual influenza and pneumococcal vaccination is a cost-effective disease prevention strategy for the elderly in Shenzhen, China.