Effectiveness of influenza vaccine among the population in Chongqing, China, 2018-2022: A test negative design-based evaluation

• Main Authors: Shuang Yang (Author), Qing Wang (Author), Tingting Li (Author), Jiang Long (Author), Yu Xiong (Author), Luzhao Feng (Author), Yong Zhao (Author), Jule Yang (Author), Wenge Tang (Author), Huadong Zhang (Author), Li Qi (Author)
• Format: Book
• Published: Taylor & Francis Group, 2024-12-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.

Summary

Influenza vaccination is the most cost-effective strategy for influenza prevention. Influenza vaccines have been found to be effective against symptomatic and medically attended outpatient influenza illnesses. However, there is currently a lack of data regarding the effectiveness of inactivated influenza vaccines in Chongqing, China. We conducted a prospective observational test-negative design study. Outpatient and emergency cases presenting with influenza-like illnesses (ILI) and available influenza reverse transcription polymerase chain reaction (RT-PCR) were selected and classified as cases (positive influenza RT-PCR) or controls (negative influenza RT-PCR). A total of 7,307 cases of influenza and 7,905 control subjects were included in this study. The overall adjusted influenza vaccine effectiveness (IVE) was 44.4% (95% confidence interval (CI): 32.5-54.2%). In the age groups of less than 6 years old, 6-18 years old, and 19-59 years old, the adjusted IVE were 32.2% (95% CI: 10.0-48.9%), 48.2% (95% CI: 30.6-61.4%), and 72.0% (95% CI: 43.6-86.1%). The adjusted IVE for H1N1, H3N2 and B (Victoria) were 71.1% (95% CI: 55.4-81.3%), 36.1% (95% CI: 14.6-52.2%) and 33.7% (95% CI: 14.6-48.5%). Influenza vaccination was effective in Chongqing from 2018 to 2022. Evaluating IVE in this area is feasible and should be conducted annually in the future.

Item Description

10.1080/21645515.2024.2376821
2164-554X
2164-5515