[Effectiveness of influenza vaccination for school-age children in preventing school absenteeism in Shenzhen: an empirical study].

Objective: To assess the impact of vaccination at school and influenza vaccination rates among school-age children on school absenteeism in Shenzhen. Methods: The study subjects were primary school students in Shenzhen. School absenteeism panel database from December 2017 to June 2020 of 286 primary schools in Shenzhen was merged with vaccination rates and organizational patterns (i.e., vaccination at school vs. non-school) data of 9 districts in Shenzhen after influenza vaccination for children. The outcome was the number of school absenteeism. The treatment and control groups were distinguished by organizational patterns and district vaccination rates. Difference-in-Difference (DiD) Poisson regressions were used to analyze the effectiveness of vaccination at school and higher vaccination rates. Besides, a robustness test was performed on the regression results. Results: Poisson regression analysis and robustness test of regression results showed that vaccination at school and higher vaccination rates effectively reduced the risk of school absenteeism, with effectiveness against absenteeism of 32.6% (95%CI: 17.0%-45.3%, P<0.01) and 53.0% (95%CI: 42.1%-61.8%, P<0.01), respectively. Conclusion: A free influenza vaccination program for school-age children in Shenzhen and prioritizing school-based vaccination may be an effective measure to reduce the risk of school absenteeism.