BackgroundThe need for patient engagement in health research has been increasingly acknowledged and accepted in recent years. However, implementation is still limited due to lack of evidence on its value and lack of guidance on how to implement patient engagement. This study aims to provide insight into the contribution of patient engagement in the RECOVAC project, which studied COVID-19 vaccination in kidney patients, and formulate concrete practice-based action perspectives for patient engagement.MethodsWe used a qualitative participatory mixed methods approach, based on the Patient Engagement Monitoring and Evaluation (PEME) framework. Patient engagement and data collection were based on the Reflexive Monitoring in Action (RMA) approach. Data collection included participant observations, open ended questionnaires and interactive reflection sessions. Qualitative analysis was done via a thematic approach.ResultsWe have described the process of patient engagement systematically, provided insight in its value and found that there is a need for clear aims, expectations and preparations from the start of the engagement process. We have shown that reflection throughout the process is of utmost importance and the same applies to clear communication between researchers and patient representatives. By being part of the consortium patient representatives had direct access to information, straight from the source, on for example the vaccination schedule and medication availability and had indirect influence on decisions made by the National Institute for Public Health and the Environment (RIVM) on preventive measures and treatment against COVID-19. Having experienced patient representatives is important, otherwise training needs to be provided. We also found that patient engagement had impact on conduct and outcomes of research activities itself and may have impact on future research and patient engagement activities in general.ConclusionPatient engagement has changed the course of the project. Concrete practice-based action perspectives have been formulated, which are already being implemented by the Dutch Kidney Patients Association (NVN). Studying patient engagement in a high pace project with high public interest has resulted in lessons learned and will help prepare and implement patient involvement in future research projects.Clinical trial registrationThe RECOVAC studies in which the patient engagement took place are registered at clinicialtrial.gov (NCT04741386 registration date 2021-02-04, NCT04841785 registration date 2021-03-22 and NCT05030974 registration date 2021-08-20).