Abstract
The mRNA COVID-19 vaccines were rapidly deployed worldwide to reduce morbidity and mortality from SARS-CoV-2 infection. While many individuals recovered fully, a subset developed persistent symptoms following natural infection, now recognised as Post-Acute COVID-19 Syndrome (PACS or Long COVID).
Following widespread vaccine rollout, it has become evident that a smaller but clinically significant proportion of recipients experience chronic, multisystem symptoms with similar but characteristic patterns, now termed Post-Acute COVID-19 Vaccination Syndrome (PACVS).
The SARS-CoV-2 spike protein has been shown to be intrinsically pathogenic, whether produced during natural infection or via mRNA vaccination. In PACVS, persistent circulating spike protein and/or markedly elevated anti-spike antibodies have been documented, often accompanied by immune dysregulation and the production of autoantibodies, particularly against G-protein-coupled receptors (GPCRs). Fatigue, cardiovascular and neurological symptomatology with dysautonomia, predominate.
This paper presents two detailed case histories that illustrate the clinical spectrum of PACVS and the associated immune abnormalities, both with either residual spike protein or high antispike antibodies some 31/2 years after vaccination. The likely pathophysiological mechanisms linking spike protein exposure to these findings are discussed. A further paper will discuss possible therapeutic interventions.