Introduction: Public awareness and support for secondary health data use may vary by health care experience and participant demographics. Those in England can “opt out” of data secondary use. We explored the awareness, support for and concerns about anonymised healthcare data secondary use and the NHS data opt-out system amongst patients, carers, healthcare staff and the public within the West Midlands. Methods: A patient and public engagement program was completed between February 2019 and July 2020 through PIONEER, conducted at University Hospitals Birmingham NHS Foundation Trust and public venues. This program included patient and public workshops, questionnaires regarding anonymised health data use and feedback discussion groups. Results: Central themes of the benefits and concerns for health data use were agreed by patient and public participants. Key public and patient priorities were projects leading to patient benefit, oversight by the NHS as a trusted organisation, increasing awareness of the NHS data opt-out, and ongoing transparency and public/patient involvement. Questionnaires (308 respondents) showed 31.8% were aware of the NHS data opt-out. 93.8% were happy for their data to be used for NHS research, 84.8% for academic research and 68.4% by health companies. However, opinion varied across groups (age, gender or public, patient, NHS staff and volunteers).Four action points were agreed in workshops based on these results: namely, education regarding the NHS opt-out, increased public awareness of data use, public involvement in data requests with NHS oversight, and transparency including reporting data use and subsequent patient benefit. Conclusion: Use of anonymised healthcare data for secondary purposes is acceptable to most patients, carers and healthcare workers. However, awareness is limited, including of the NHS data opt-out system. Initiatives to improve awareness and publicise potential benefits are needed amongst patients, healthcare staff and the public. Funding Statement: This work was supported by PIONEER, the Health Data Research UK (HDR-UK) Health Data Research Hub in acute care. HDR-UK is an initiative funded by UK Research and Innovation, Department of Health and Social Care (England) and the devolved administrations, and leading medical research charities. Declaration of Interests: CA, BC, KD, GP, EM, MO’H, CM, AI, CC, ML, SM, SG, SP, JA, RD, AR, HF have no conflicts of interest. GG reports funding from HDR-UK. AKD reports funding from HDRUK, The Wellcome Trust and Fight for Sight. ES reports funding from the Wellcome Trust, MRC, HDR-UK, Alpha 1 Foundation (A1F), British Lung Foundation and NIHR. Ethics Approval Statement: PIONEER is an ethically-approved research database and analytical environment (East Midlands – Derby Research Ethics 20/EM/0158). This PPIE work was conducted following ethical approval from the University of Birmingham Ethical Committee (reference ERN_20-0118).