Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious respiratory virus which is the causative agent behind the Coronavirus Disease 2019 (COVID-19) pandemic. It is increasingly clear that recovered individuals, even those who had mild COVID-19, can suffer from persistent symptoms for many months after infection, which is popularly referred to as ‘long COVID’. However despite the plethora of research on COVID-19 relatively little is known about the molecular underpinnings of these long-term effects. We have undertaken an integrated analysis of immune responses in blood at a transcriptional, cellular, and serological level at 12-, 16-, and 24-weeks post-infection (wpi) in 69 patients recovering from mild, moderate, severe, or critical COVID-19 in comparison to healthy uninfected controls. We identified significant perturbations to gene expression in COVID-19 convalescents until at least 6 months post-infection. This was marked by hundreds of differentially expressed genes, a strong up regulation of cell cycle and infection related processes and alterations in non-coding RNAs such as MALAT1. Blood transcriptional module analysis highlighted variable rates of recovery in the transcriptome of COVID-19 convalescents, correlations between the antibody response and transcriptome and associations with ongoing symptoms. In conclusion, variation in the rate of recovery from infection at a cellular and transcriptional level may explain the persistence of symptoms associated with long COVID in some patients.