Combining predictive markers for severe COVID-19: Torquetenovirus DNA load and SARS-CoV-2 RNAemia

RATIONALE/OBJECTIVES: SARS-CoV-2 is the cause of worldwide COVID-19, which severity has been linked to the immune and inflammatory response. Here, we investigate Torquetenovirus (TTV) DNA load - a marker reflecting the intensity of the overall immune response - as well as SARS-CoV-2 RNAemia and IgM/IgG antibodies in COVID-19-positive patients. METHODS: Two hundred and fifteen COVID-19-positive patients were enrolled, including 87 severe cases and 128 mild-moderate cases. SARS-CoV-2 RNAemia and IgM/IgG antibodies, as well as TTV DNA loads, were measured on longitudinal plasma samples. RESULTS: The rate of severe cases was higher in patients with low TTV DNA load in plasma considering a threshold of 700 copies/mL. In severe patients, SARS-CoV-2 RNAemia positivity rates were higher than those in mild-moderate cases at any timepoint. When combined, TTV DNA load and SARS-CoV-2 RNAemia allowed to predict the outcome of COVID-19 infection, with a higher risk (HR=12.4) of ICU admission in patients with low TTV DNA load and positive SARS-CoV-2 RNAemia. CONCLUSIONS: TTV DNA load and SARS-CoV-2 RNAemia may be effective, non-invasive markers reflecting disease severity and poor outcome that could be conveniently measured in a clinical laboratory setting, as soon as COVID-19 diagnosis is made.