Interestingly, parallel to an increase in HERV transcripts in blood samples from COVID-19 patients (Balestrieri et al., 2021; Guo et al., 2022), we demonstrated that HERV-W ENV protein expression was high in the leukocytes and correlated with the markers of T-cell differentiation and exhaustion and cytokine levels, suggesting the involvement of ENV protein in COVID-19 immunopathology (Balestrieri et al., 2021). Here, ERVW-1 is linked to COVID-19.