The T cell response to SARS-CoV-2 mRNA vaccine in adults with high exposure to perfluoroalkyl substances from Ronneby, Sweden

BACKGROUND: Perfluoroalkyl substances (PFAS) have been associated with impaired antibody levels after childhood vaccinations and immunosuppressive effects in animals. However, the in vivo effects of PFAS on antigen specific human T cell responses have not been investigated in adults. In Ronneby, Sweden, the drinking water of one of the water works was previously highly contaminated with primarily perfluorohexane sulfonic acid (PFHxS) and perfluorooctane sulfonic acid (PFOS). The COVID-19 vaccination scheme presented the possibility to assess antigen specific T cell function after vaccination in adults with high PFAS serum levels.

OBJECTIVES: To investigate the relationship between PFAS exposure and T cell responses after COVID-19 vaccination in a population with varied PFAS exposure.

METHODS: 116 COVID-19 naïve individuals from Ronneby and a background exposed group were included from the PFAS Immune Response After COVID-19 Vaccination cohort (PIRVACoV). All participants received two doses of Spikevax® (Moderna) vaccine. Blood T cells were stimulated with overlapping peptides based on the SARS-CoV-2 spike protein and their production of the cytokines IFN-γ, IL-2, and TNF were measured. The general immune response was assessed by measurement of phytohemagglutinin stimulated cytokines and total immunoglobulin serum levels. Adjusted mixed linear regressions were fitted against measured, address-based and prenatal PFAS exposure indices.

RESULTS: PFAS median serum levels differed greatly between participants ever having had contaminated drinking water at home (PFOS 47 ng/mL, 5th to 95th percentile 6-221 ng/mL) and the background group (PFOS 4 ng/mL, 2-9 ng/mL). PFAS exposure was not associated with SARS-CoV-2 specific T cell cytokine responses (e.g., measured PFOS to IFN-γ: +3% per interquartile range PFOS, 95% confidence interval: -10, 17), nor general immune response.

CONCLUSIONS: This study indicates, in concordance with the PIRVACoV antibody study and other antibody PFAS/COVID-19 studies, that PFAS exposed, healthy adults mount adequate immune responses to mRNA COVID-19 vaccination. EudraCT-number: 2021-000842-16.