Long Covid: a longitudinal perspective of cognitive impairment and symptom trajectories in a working age sample

SARS-CoV-2, has been shown to induce inflammation in the hippocampus which may lead to prolonged memory deficits in people with Long Covid (pwLC). While Long Covid (LC) is estimated to affect over 65 million people worldwide, its long-term cognitive and functional sequalae remain poorly understood. Using a mixed-methods longitudinal design, this thesis investigated the symptom trajectories of LC. It also examined the lived experiences of pwLC, integrating qualitative insights alongside quantitative data. People of working age (N = 68), most of whom (81%) had a formal LC diagnosis, completed sub-tests of the BIRT Memory and Information Processing Battery (BMIPB-II), a word categorisation and recognition task (Addante et al., 2012) and health surveys at three time points, from March 2023 to March 2025 with an average of 19 months between the first and third assessment (SD = 1.41). Qualitative data from open-ended survey responses and semi-structured interviews, were examined using thematic analysis to capture lived experiences. Finally, a study protocol was designed to explore cortical dynamics of memory encoding and retrieval, to further delineate the neurophysiological underpinnings of the condition. Persistent impairments in memory were observed for up to 60 months since LC diagnosis. Verbal learning and retention and speed of information processing were impaired on all assessments. Visual memory, semantic categorisation accuracy and speed were preserved. Participants self-reported up to 34 LC symptoms. The most frequent were fatigue, memory and concentration problems. PwLC demonstrated elevated fatigue compared to controls, which correlated with low quality of life. Linear mixed modelling showed changes over time for some of the cognitive performance measures, but not on all other measures. Lived experience perspectives demonstrated the complex and multifaceted challenges of living with LC. The findings from this thesis evidence the persistent cognitive and functional deficits in pwLC, and may inform the development of better diagnosis and support pathways for pwLC.