Association between early SARS-CoV-2 viral rebound and post-COVID conditions among immunocompromised patients: cohort study.

Objectives: Immunocompromised status has been shown to be a risk factor for SARS-CoV-2 viral rebound. However, no studies have assessed the long-term clinical consequences of viral rebound in the immunocompromised population. This study aimed to examine the association of early viral rebound with postacute conditions among immunocompromised patients.

Methods: We conducted a retrospective cohort study using territory-wide electronic health records from the Hospital Authority and the Department of Health in Hong Kong. The study cohort consisted of immunocompromised adults aged 18 years or older who tested positive for SARS-CoV-2 between 26 February 2022 and 9 November 2023, and who were hospitalized with COVID-19. Patients were classified as having early viral rebound or not having early viral rebound based on the cycle threshold values within 21 days of the positive RT-PCR test result. The primary outcome was postacute all-cause inpatient death, evaluated starting from 21 days after the positive RT-PCR test.

Results: A total of 1296 immunocompromised adults were included in this study (46.4% [601 of 1296] were female; median [interquartile range] age, 68 [59-76] years). In all, 22.3% (289 of 1296) patients were categorized as having early viral rebound. Haematological malignancy was significantly associated with early viral rebound (hazard ratio 1.52, 95% CI 1.09-2.12, p 0.014). Early viral rebound was significantly associated with a higher risk of postacute inpatient death (hazard ratio 1.53, CI 1.16-2.02, p 0.002).

Conclusions: This study demonstrated an association between early viral rebound and post-COVID mortality among immunocompromised individuals.