OBJECTIVES: Vaccination of the at-risk population against influenza by pharmacists was widely implemented in France in 2019. Only little data are available about the population using this service. We have explored the characteristics and determinants of the at-risk population vaccinated in pharmacy through a web-based cohort during the 2019-20 winter season. METHODS: This study is based on the data of the profile survey of at-risk over-18 vaccinated participants of the cohort GrippeNet.fr, for the 2019-20 winter season. Population characteristics were described using the inclusion questionnaire data. Factors associated with pharmacy influenza vaccination were analysed through a logistic regression model. KEY FINDINGS: In total, 3144 people were included in the study. 50.2% (N = 1577) of them were women and 65.5% (N = 2060) were over 65 years old. 29.5% (N = 928) of participants were vaccinated in pharmacy. 73.1% (N = 678) of participants vaccinated in pharmacy were over 65 years old and 46.6% (N = 432) had a treatment for one or more chronic disease. Factors positively associated with being vaccinated by a pharmacist were: being a man (OR = 1.25, 95% confidence interval [1.06-1.47]), being over 65 years old (OR = 1.97 [1.49-2.63]), living in a test region (OR = 1.62 [1.29-2.02] and 1.72 [1.43-2.07] depending on the year of the implementation of the experimentation) and being vaccinated against influenza in 2018/2019 (OR = 1.71 [1.32-2.21]). Factors negatively associated were: taking a chronic treatment (OR = 0.83 [0.70-0.97]), and living alone (OR = 1.40 [1.17-1.67] and being in contact with sick people (OR = 0.68 [0.50-0.93]). CONCLUSIONS: This study confirmed some factors associated with pharmacy influenza vaccination and feeds the debate on other uncertain factors. These findings can support public health authorities' willingness to enhance pharmacists' involvement in the future country-wide vaccination campaign. Our study also highlights the necessity to further investigate the impact of this measure in a few years.