ABSTRACT
While evidence for pre-existing SARS-CoV-2-cross-reactive CD4+ T cells in unexposed individuals is increasing, their functional significance remains unclear. Here, we comprehensively determined SARS-CoV-2-cross-reactivity and human coronavirus-reactivity in unexposed individuals. SARS-CoV-2-cross-reactive CD4+ T cells were ubiquitous, but their presence decreased with age. Within the spike glycoprotein fusion domain, we identified a universal immunodominant coronavirus-specific peptide epitope (iCope). Pre-existing spike- and iCope-reactive memory T cells were efficiently recruited into mild SARS-CoV-2 infections and their abundance correlated with higher IgG titers. Importantly, the cells were also reactivated after primary BNT162b2 COVID-19 mRNA vaccination in which their kinetics resembled that of secondary immune responses. Our results highlight the functional importance of pre-existing spike-cross-reactive T cells in SARS-CoV-2 infection and vaccination. Abundant spike-specific cross-immunity may be responsible for the unexpectedly high efficacy of current vaccines even with single doses and the high rate of asymptomatic/mild infection courses.
Subject(s)
Severe Acute Respiratory Syndrome , COVID-19ABSTRACT
Objective: Characterization of the clinical features of patients with persistent symptoms after mild to moderate COVID-19 infection and exploration of factors associated with the development of Chronic COVID-19 Syndrome (CCS). Methods: Setting: Charite Fatigue Center with clinical immunologists and rheumatologist, neurologists and cardiologists at Charite University hospital. Participants: 42 patients who presented with persistent moderate to severe fatigue six months following a mostly mild SARS-CoV-2 infection at the Charite Fatigue Center from July to November 2020. Main outcome measures: The primary outcomes were clinical and paraclinical data and meeting diagnostic criteria for Chronic Fatigue Syndrome (ME/CFS). Relevant neurological and cardiopulmonary morbidity was excluded. Results: The median age was 36.5, range 22-62, 29 patients were female and 13 male. At six months post acute COVID-19 all patients had fatigue (Chalder Fatigue Score median 25 of 33, range 14-32), the most frequent other symptoms were post exertional malaise (n=41), cognitive symptoms (n=40), headache (n=38), and muscle pain (n=35). Most patients were moderately to severely impaired in daily live with a median Bell disability score of 50 (range 15-90) of 100 (healthy) and Short Form 36 (SF36) physical function score of 63 (range 15-80) of 100. 19 of 42 patients fulfilled the 2003 Canadian Consensus Criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). These patients reported more fatigue in the Chalder Fatigue Score (p=0.006), more stress intolerance (p=0.042) and more frequent and longer post exertional malaise (PEM) (p= 0.003), and hypersensitivity to noise (p=0.029), light (p=0.0143) and temperature (0.024) compared to patients not meeting ME/CFS criteria. Handgrip force was diminished in most patients compared to healthy control values, and lower in CCS/CFS compared to non-CFS CCS (Fmax1 p=0.085, Fmax2, p=0.050, Fmean1 p=0.043, Fmean2 p=0.034, mean of 10 repeat handgrips, 29 female patients). Mannose-binding lectin (MBL) deficiency was observed frequently (22% of all patients) and elevated IL-8 levels were found in 43% of patients. Conclusions: Chronic COVID-19 Syndrome at months 6 is a multisymptomatic frequently debilitating disease fulfilling diagnostic criteria of ME/CFS in about half of the patients in our study. Research in mechanisms and clinical trials are urgently needed.