High TTV Load Before First Vaccine Dose is Associated with Poor Serological Response to Covid-19 Vaccination in Lung Transplant Recipients

ABSTRACT

Purpose: Torque tenovirus (TTV), a highly prevalent virus which is not known to cause pathology in humans, is currently being investigated as a marker of immunosuppression. In this study we investigated if the TTV load measured prior to COVID-19 vaccination can predict the serological response to the COVID-19 vaccine, measured 28 days after the second vaccination dose. Method(s) The humoral response to the mRNA 1273 vaccine (Moderna) was assessed in Lung transplant recipients (LTR) who received a transplant between 4 and 237 months prior, by measuring Spike-specific IgG levels at 28 days after the second vaccination. Antibody concentrations of >10 BAU/ml were considered reactive. TTV loads were determined by PCR and Pearson's correlation coefficient was calculated to correlate serological responses to TTV load. Patient characteristics, including reasons for transplantation, antirejection treatment, age and time since transplantation, were recorded to assess associations between these factors and vaccination response or TTV levels. Result(s) 103 LTR were included of which 41 (40%) showed some response (>10 BAU/ml) to the vaccine at 28 days after the second vaccination. 61 (60%) were non-responders. TTV loads at baseline varied between negative and 10E9 copies/ ml. The TTV loads were found to correlate with IgG levels and the with the percentage of responders 28 days after the second vaccination (=<0.001). TTV loads also correlated strongly with the time since transplantation. High TTV levels occurred predominantly in patients who were shorter after transplantation (p=0.0001). Conclusion(s) This study shows an association between pre-vaccination TTV load and humoral response to the SARS-CoV-2 vaccine, which correlate with the time after transplantation. We recommend that TTV load measurements are included in further vaccination efficacy studies in immunocompromised cohorts. If the TTV load is indeed a predictor of vaccine response, this could be used as a potential guidance for optimizing vaccination response.