Summary
A small cross-sectional preprint reports overlapping clinical and immune findings among people with post-acute COVID-19 and a group with persistent symptoms following COVID-19 vaccination. The results describe similarities between the groups but do not determine what causes the symptoms.
A medRxiv preprint reports clinical and immune similarities between people with post-acute COVID-19 syndrome (PACS) and a group with persistent symptoms following COVID-19 vaccination, called post-acute COVID-19 vaccination syndrome (PACVS) in the study. The cross-sectional study compared 28 people with PACS, 29 with PACVS and 16 convalescent controls. Several symptoms were more severe in the PACS group, but the researchers found substantial overlap between the two patient groups.
The findings describe patterns in these participants; they do not establish that the same process causes symptoms in both groups. The report is a preprint, and its results should be read as preliminary.
What the researchers measured
Participants completed ME/CFS-related symptom questionnaires and the Bell Score. The researchers also examined immune-cell profiles and tested blood for antibodies against selected G protein-coupled receptors (GPCRs), circulating SARS-CoV-2 Spike protein and Epstein–Barr virus (EBV) load.
GPCRs are cell-surface proteins involved in transmitting signals. The study measured antibodies and T cells reactive to β1- and β2-adrenergic receptors and M3 and M4 muscarinic receptors, alongside T-cell responses to Spike. These laboratory measures show immune reactivity; their presence alone does not establish that it is driving symptoms.
Similarities and differences between the groups
The researchers reported comparable GPCR autoantibody profiles in the PACS and PACVS groups. β2-adrenergic receptor autoantibodies were increased in both patient groups compared with convalescent controls. T cells reactive to the tested adrenergic and muscarinic receptors were also increased, while Spike-specific CD4+ T cells were reduced relative to controls.
Conventional immune-cell profiling showed a closer match between the patient groups than between either group and the controls: only three of 57 measured parameters differed between PACS and PACVS in unadjusted analyses, while both groups had multiple differences from controls. Circulating Spike protein was detected in both patient groups, with its highest prevalence in PACVS. EBV reactivation was rare.
What the comparison can tell us
The results point to overlapping clinical and immune features in the two groups studied. The cross-sectional design captures measurements at one point in time, so it cannot determine whether these immune findings preceded, followed or contributed to participants’ symptoms. Nor does similarity in measured features establish that PACS and PACVS have an identical underlying mechanism.
The authors suggest investigating whether treatments being explored for PACS might also be relevant to PACVS. This study identifies a research question rather than showing that any such treatment works for either group.