TTV Load is Associated with SARS-CoV-2 Vaccination Response in Lung Transplant Recipients

PURPOSE: Although the currently approved COVID-19 vaccines are highly effective, SARS-CoV-2-specific immune responses are diminished in lung transplant recipients (LTR), probably due to immunosuppression (IS). There is currently no marker of IS that can be used to predict vaccination responses. Here, we study if torque tenovirus (TTV) can be used as a predictive marker. METHODS: The humoral response to the mRNA-1273 vaccine was assessed in 103 LTR, who were vaccinated 4 to 237 months after Lung transplantation. Spike (S)-specific IgG levels were measured at baseline, 28 days after first, and 28 days after the second vaccination. TTV loads were determined by RT-PCR and Pearson's correlation coefficient was calculated to correlate serological responses to TTV load. RESULTS: Humoral responses to the vaccine COVID-19 vaccination were found in 41/103 (40%) LTR at 28 days after the second vaccination. 62 /103 (60%) had no detectable antibodies. TTV loads at baseline correlated with S-specific antibodies and the percentage of responders (=<0.001) (Fig 1). TTV loads also strongly correlated with the time since transplantation, indicating that participants with lower TTV loads were longer after transplantation. CONCLUSION: This study shows an association between baseline TTV load and mRNA-1273-induced S-specific antibodies. If the TTV load is indeed a predictor of vaccination responses, this can be used in the future as a potential guidance for optimizing vaccination regimens. Therefore, we recommend that TTV load measurements are included in further vaccination efficacy studies in immunocompromised cohorts.