BackgroundPublic and patient involvement and engagement (PPIE) is an important part of research. The inclusion of PPIE in research is becoming more widespread, however, there are some areas where it is still uncommon. For example, undertaking PPIE in secondary analysis projects is uncommon and PPIE with difficult to reach populations and vulnerable groups can be seen as being too difficult to facilitate. The aim was to summarise the approach to and findings of the PPIE undertaken as part of a programme of secondary analysis with a vulnerable, hard to reach population; residents of residential care facilities (RCFs), during the COVID-19 pandemic.MethodsAs part of a project to develop a publically available database of statutory notifications of adverse events from RCFs in Ireland, residents (n = 9) from RCFs for older people and people with disability were telephone interviewed. Residents were engaged through gatekeepers and posted participant information and consent forms. Themes were identified using content analyses of interview notes.ResultsThree parent themes were identified, each with two subthemes: privacy concerns, enthusiasm and dissemination of research findings. Residents highlighted the importance that no personal information be shared in the database. Once data were anonymized, residents thought that the database should be published and shared. Residents reported being happy about research being undertaken using the data and thought that publishing the database would help inform the public about RCFs. Completing a PPIE project with a vulnerable group during the global COVID-19 pandemic required planning and resources. Resources included finances, time and expertise.ConclusionsThe involvement of residents informed the data inclusion in the published database and the approach taken in the protection of personal data. Enthusiasm for publication and research using the database by residents encouraged the developers as it was considered something that was wanted by residents. The benefits of PPIE can be achieved with vulnerable groups during unprecedented times with the appropriate planning. It requires dedication of time, finances and expertise. Overcoming the obstacles was achievable and worthwhile. The approach outlined can be used as an example to support PPIE in secondary analysis projects and or with vulnerable groups.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40900-023-00416-7.