Speakers - 2025

Juan Li

  • Designation: Beijing Center for Disease Prevention and Control (Beijing CDC)
  • Country: China
  • Title: Effectiveness of Influenza Vaccines in Preventing Acute Cardiovascular Events Within 1 year in Beijing, China

Biography

Juan Li, Ph.D. in Epidemiology and Health Statistics from Peking University, is a researcher at Beijing CDC, focusing on vaccine-preventable disease surveillance and evaluation. She has over 40 papers, 4 compiled/translated works, led/participated in 10 projects, and won the 2017 Chinese Preventive Medicine Association's Science and Technology Third Prize and the 2020 Beijing March 8th Red Banner Medal. Academic roles include Beijing health popularization expert and association committee member.

Abstract

Abstract: 

Background: Cardiovascular disease is the leading cause of death globally and in China, with accumulating evidence linking acute respiratory infections to increased risk of acute cardiovascular events. Influenza vaccination, effective in preventing acute respiratory infections, may also reduce cardiovascular complications, but controversies persist regarding its protective effects across different populations and study designs. Previous research has highlighted inconsistencies due to confounding biases, varying study populations, and limited data from Chinese populations using self-controlled case series (SCCS) designs, which better control for non-time-varying confounders. 

Objective: This study aimed to investigate the protective effect of influenza vaccination against acute cardiovascular events within one year using an SCCS design, based on hospitalization data from Beijing, China. It sought to clarify the duration of protection, variations across subgroups (e.g., age, cardiovascular history), and potential confounding by acute respiratory infections, providing evidence to optimize cardiovascular disease prevention strategies. 

Methods: Participants included 1,647 permanent Beijing residents (median age 65 years, 38.43% female) who received influenza vaccination between 2016–2018, had no subsequent vaccinations within two years, and experienced at least one acute cardiovascular event within two years post-vaccination. The SCCS design defined a 2-year observation period: exposure period (29–365 days post-vaccination) and control periods (0–28 days and 366–730 days post-vaccination). Relative incidence (RI) and 95% confidence intervals (CI) were calculated, adjusting for acute respiratory infections and seasonal effects. Stratified analyses by age, cardiovascular history, and other factors were performed. 

Results: The risk of acute cardiovascular events during 29–365 days post-vaccination was 0.76 times the baseline (RI=0.76; 95% CI: 0.68–0.84). Protective effects were more pronounced in younger participants (P=0.043) and those without cardiovascular history (P<0.001), with no significant impact from acute respiratory infections (P=0.986) or vaccination frequency (P=0.272). Influenza vaccination reduced risks of ischemic stroke (RI=0.58; 95% CI: 0.49–0.69) and myocardial infarction (RI=0.74; 95% CI: 0.55–0.99) within one year. Sensitivity analyses confirmed stability, and protection persisted for at least two years. 

Conclusion: Influenza vaccination reduces the risk of acute cardiovascular events for at least one year, with stronger protection in younger individuals and those without prior cardiovascular disease. These findings support influenza vaccination as a potential primary and secondary prevention strategy for cardiovascular disease, highlighting its public health significance in China.

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