Several major epidemiological studies have been funded in the UK with the goal of better understanding the epidemiology of persistent symptoms following SARS-CoV-2 infection. Investigators from nine of these studies formed the National Long COVID Research Working Group in 2021 to share key findings and methodological developments and explore ways of working across projects1.

Seven of these studies have worked substantively with diverse public and patient members and support groups, and have gone on to create participant involvement groups or panels specific to their research (Table 1). The large volume of people living with long COVID2 and the willingness of individuals and support groups to engage with these studies, as well as the barriers to operating during periods of pandemic control measures, have provided unique opportunities and challenges for patient and public involvement (PPI).

Table 1 Patient and public involvement within epidemiological studies of long COVID in the UK

A particular example of the success of PPI is the Therapies for Long COVID in non-hospitalized individuals (TLC) study3, during which patient partners identified the need to develop a new Symptom Burden Questionnaire for Long COVID (SBQ-LC)4. Individuals with long COVID were actively involved in generating item content for the SBQ and assisted with recruitment. The SBQ-LC has since been licensed more than 90 times across 50 countries. In addition to this important contribution, patient partners also actively coproduced a study to test the feasibility and acceptability of delivering non-pharmacological, self-management interventions remotely in the community, shaping the study design and co-selecting intervention resources.

Advocacy and support groups have been invaluable to individuals with long COVID and have acted as conduits for their involvement in research studies, through a diverse network of individuals and carers with a wide range of lived experience. Members of these groups often assist with public engagement, which helps with the recruitment of study participants, as well as with publicizing events such as study webinars, distributing questionnaires and disseminating results. However, there is often a lack of diversity among participants, who are often of similar age, sex, ethnicity, education level and professional status. As a result, the CONVALESCENCE long COVID study proactively recruited from underserved communities and included questions on equality and diversity in its PPI recruitment materials. Extensive training from the study PPI team was also provided so that participants felt qualified to contribute in areas such as quantitative data interpretation. When selecting participants, studies from the Working Group have included a diverse PPI membership, delivering individualized training and discussions on preferences on involvement.

A particular area of learning relates to the establishment of patient advisory groups (PAGs). Diversity of participants can be improved by recruitment from several PPI networks rather than a single source. Clear pathways for inviting new members to join PAGs are needed to ensure that they are sustainable. It is important that PPI members receive regular updates and information on the project and are clearly informed of the purpose and importance of their involvement. PPI activities can be greatly strengthened, coordinated and made sustainable throughout a project by a dedicated and trained PPI lead, which is a crucial role in long COVID research.

Researchers should continually revisit what different PPI members want to contribute and can contribute, based on skill set, interests, returning to work and other commitments, as well as on the restrictions that come with having a chronic condition with a relapsing and remitting nature where a main symptom is fatigue. Different studies, or different aspects of a study, may have different requirements for PPI members or may benefit from PPI members with specific experiences, knowledge or skills. Certain studies are more complicated, more cognitively challenging or more demanding of PPI members’ time than others. Studies can benefit from working with PPI members with extensive knowledge and experience of long COVID, as well as those who are able to attend and actively contribute to frequent meetings, to ensure that effective PPI is ingrained throughout the study. This can include working on various aspects of the study such as study design, contributing to patient-facing materials, interpreting results, coauthoring papers and participating in public engagement events.

Researchers may not always be aware of how much PPI can improve their research. Researchers should consider the experience, skills and capabilities of each PPI member and what they want to contribute to, rather than having this be decided, perhaps inappropriately, by the research team.

Individuals with long COVID often experience fatigue and sometimes have cognitive dysfunction, which may require adjustments as with any disability. PPI meetings should be flexible (for example, in timing and duration) and consider individual needs, with all materials and documents for review provided with sufficient advance notice. Other meeting adjustments should include taking into account the potential need for breaks and allowing cameras to be optional, as PPI members may tire, experience sensory or vision issues, or be concerned about appearing on camera.

The pandemic presented logistical challenges to working with participants on research due to strict public health measures such as social distancing. However, a rapid upskilling in the use of online communication technology has given studies from the Working Group access to a wide range of patient contributors from across the UK. Although carrying out PPI activities online raises concerns around digital exclusion, studies such as CLoCk have found that online recruitment and virtual meetings helped achieve more representative geographical coverage and diversity from across the UK, in terms of both ethnicity and socioeconomic status.

The level of patient involvement we have experienced has undoubtedly strengthened the applicability and rigor of our findings and increased public trust in the veracity of these studies. There remains a limited understanding on the causes of long COVID and the development of effective treatments, and so placing patients at the heart of future research in this area remains imperative5.