CROI 2022: Long COVID persists for over a year: evidence for divergent immune responses
Kirk Taylor, HIV i-Base
Approximately 20% of the studies at CROI 2022 had a link to COVID-19, included several focused on long COVID (PASC).
A French cohort study reported persistence of COVID symptoms a year after hospital admission that was was more common in women than men with 25% of people not returning to work after a year. 
Another study differentiated people with long COVID by antibody responses, although the clinical impact this has on disease progression was unclear. 
Persistent COVID symptoms 12 months post-hospital admission
A prospective cohort study followed people hospitalised with COVID (n=737) for a year after admission.
Participants were male (64%) with median age of 61 years (IQR: 51 to 70), 37% had been admitted to ICU and 27% had ≥3 symptoms at 12 months.
Follow-up visits were conducted at 3, 6 and 12 months post-admission. Participant interviews assessed quality of life, COVID symptoms and psychological distress. The most reported symptoms were fatigue (46%), shortness of breath (33%) and joint pain (21%).
Overall, 25% of participants had not returned to work after a year. This was more common for women (34%) than men (24%). Women also reported more COVID symptoms, depression, and anxiety.
Differential antibody responses of people with long COVID
Antibody responses were evaluated from people with long COVID who had persistent or resurgent symptoms three months post-infection. 
Participants either had long COVID (n=44), had recovered from COVID (n=25) or were uninfected (n=14).
Anti-COVID spike IgG and IgA antibody titres were measured and 48% of long COVID patients were seropositive. Seropositive patients had increased T Cell responses to inflammatory stimuli and COVID proteins in vitro. The seronegative group responses were not statistically different to people who had recovered.
These data show differences in the adaptive immune responses of people with long COVID that might help to understand reasons for disease persistence and potential therapies.
Long COVID is now a well-established complication that is complicated by very diverse symptoms and the lack of a single mechanism or simple diagnostic test,
These studies highlight the persistence of COVID symptoms and associated quality of life implications.
Kervevan and colleagues report divergent antibody responses that map to altered T cell responses but their study does not describe how these findings relate to disease progression or severity.
Further studies are required to understand the aetiology of long COVID and identify potential risk factors to facilitate clinical management.
The UK 100-page guidelines on late COVID were recently updated by NICE, the Scottish Intercollegiate Guidelines Network (SIGN) and the Royal College of General Practitioners (RCGP). 
These guidelines were also previously criticised for a limited focus on potential causes and the range of symptoms and for minimal involvement of people living with long COVID. 
- Chirouze C et al. Persistent COVID-19 symptoms are highly prevalent 12 months after hospitalisation. CROI 2022. 12-16 February 2022, virtual. Poster 628.
- Kervevan et al. Divergent adaptive immune responses define two types of long covid. CROI 2022. 12-16 February 2022, virtual. Poster 322.
- NICE et al. COVID-19 rapid guideline: managing the long- term effects of COVID-19. (3 March 2022).
- Gorna R et al. Long COVID-19 guidelines need to reflect lived experience. Lancet. 2021; 397: 455-457.