Detection of S1 spike protein in CD16+ monocytes up to 245 days in SARS-CoV-2-negative post-COVID-19 vaccine syndrome (PCVS) individuals

Abstract

Despite over 13 billion SARS-CoV-2 vaccine doses administered globally, persistent post-vaccination symptoms, termed post-COVID-19 vaccine syndrome (PCVS), resemble post-acute sequelae of COVID-19 (PASC). Symptoms like cardiac, vascular, and neurological issues often emerge shortly after vaccination and persist for months to years, mirroring PASC. We previously showed the S1 subunit of the SARS-CoV-2 spike protein persists in CD16+ monocytes after infection, potentially driving PASC. Approved vaccines (Pfizer, Moderna, Janssen, AstraZeneca) deliver synthetic S1 to elicit immunity, suggesting a shared mechanism. We hypothesized that vaccine-derived S1 persistence in CD16+ monocytes sustains inflammation akin to PASC, contributing to PCVS. We studied 50 individuals with PCVS symptoms lasting over 30 days post-vaccination and 26 asymptomatic controls, using (1) machine learning-based immune profiling to compare cytokine signatures with PASC, (2) flow cytometry to detect S1 in CD16+ monocytes, and (3) LC-MS to confirm S1 across vaccine types. We correlated S1 persistence with symptom duration and inflammation. Prior infection was excluded via clinical history, anti-nucleocapsid antibody tests, and T-detect assays, though definitive tests are lacking. Preliminary findings suggest S1 persistence in CD16+ monocytes and an associated inflammatory profile may contribute to PCVS. Further studies are needed to confirm causality and prevalence.

Keywords: CCR5; COVID-19; PASC; SARS CoV-2 S1 protein; fractalkine; non-classical monocytes.

Figure 1.

Frequency of symptoms in post-COVID-19 vaccine syndrome patient.

Figure 2.

Machine learning classification of the immune profile seen in post-vaccination individuals with PASC-like symptoms (red) compared to the immune profile in individuals with PASC (yellow) due to SARS-CoV-2 infection, mild-moderate COVID infection (blue), and severe COVID (green).

Figure 3.

Statistically significant elevation of cytokines in PCVS individuals compared to vaccinated, healthy individuals.

Figure 4.

Flow cytometric quantification of S1-containing monocyte subsets as previously performed. Increased S1-containing intermediate and non-classical monocytes in patients (12) was statistically significant compared to healthy controls (10).

Figure 5.

Liquid chromatography/mass spectrometry confirmation of S1 and S2 protein in flow cytometrically isolated cells from five post-vaccination individuals with PASC-like symptoms.

Figure 6.

Protein sequences found via liquid chromatography/mass spectrometry in CD16+ sorted monocytes.

Figure 7.

Pearson correlation coefficients between symptoms and biological markers, where red shades indicate positive correlations and blue shades indicate negative correlations.

Figure 8.

Pearson correlation coefficients between symptoms and S1 monocyte subsets, where red shades indicate positive correlations and blue shades indicate negative correlations.

Figure 9.

Mann–Whitney U test between before 120 days and after 120 days post-vaccination groups.