The estimated age-group specific influenza vaccine coverage rates in Hong Kong and the impact of the school outreach vaccination program.

Previous studies have shown that seasonal influenza strikes annually causing millions to fall sick and several hundred thousand to die globally. Hence, universal vaccination is a public health aim to control influenza. The Hong Kong Government started to introduce the School Outreach Vaccination (SOV) program in 2018 to increase vaccination rates in children. This study looked at the impact this had on hospital admissions and estimated vaccination rates in the total population, using a questionnaire-based tool. The SOV program significantly increased vaccination coverage rates with a 1% increase associated with a reduction of 4.3 influenza-related hospital admissions of school-aged children. The estimation of vaccine coverage rates among the under 5-year olds (48.5%), primary school children (69.3%) and over 65-year olds (45.7%), through the questionnaire-based tool, was within the 95% confidence interval of the coverage rates published by the Center for Health Protection of the Hong Kong Government, 47.4%, 68.1% and 45.8%, respectively. Extension of the SOV program should be considered in secondary schools to increase the coverage rates in adolescents. The questionnaire survey may inform government how to achieve universal vaccination for specific age groups.