Patients with Trichinella spiralis infection display unmodified antigen-specific immune response to SARS-CoV-2.

BACKGROUND: Through coevolution, helminths have developed immunomodulatory mechanisms that regulate exaggerated host immune responses and may influence immune responses to coinfections or vaccines. The coronavirus disease 19 (COVID-19) pandemic has raised concerns about how such infections might affect vaccine-triggered immune responses. OBJECTIVES: The aim of the study was to investigate how ongoing Trichinella spiralis infection affects the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in individuals already vaccinated or virus-primed, during Trichinella outbreak in Serbia. METHODS: Among 21 individuals who tested positive for anti-Trichinella antibodies, 15 were included in the study, which allowed for the first time to examine the impact of Trichinella infection on the humoral and cellular immune response to the SARS-CoV-2 using flow cytometry. FINDINGS: The results showed that Trichinella infection did not impair antibody production or cellular responses to SARS-CoV-2. Specifically, anti-SARS-CoV-2 antibodies and memory B cells remain unaffected, and T cells (CD4+ and CD8+) responded to SARS-CoV-2 antigens by generating pro-inflammatory cytokines. MAIN CONCLUSIONS: Trichinella spiralis infection does not disrupt the host's humoral or cellular immune response to SARS-CoV-2, suggesting that the use of Trichinella antigens for the treatment of chronic inflammatory disorders, which is promising, will not affect the host's ability to respond to future viral challenges.