Every 10-fold increase in viral load results in 26% more patient deaths: a correlation analysis

In recent years, highly pathogenic viruses have seriously threatened human health. However, it remains controversial whether viral load is the determinant for high mortality of patients. The purpose of this correlation analysis was to study the quantitative association between viral load and mortality rate following viral infections. We conducted a literature search of peer-reviewed publications in electronic databases from inception to June 30, 2018. To normalize the data, viral load ratios (log10) of non-survivors to survivors were calculated. In total, 47 valid data pairs of viral load ratio of non-survivors to survivors and the corresponding mortality rate were obtained. We calculated the possible linear regression between log1, log2, or log10 (viral load ratio) and the mortality rate. Only log10 (viral load ratio) had a good correlation (R2 > 0.5; P < 0.05). For all 47 valid data pairs, the following regression equation was obtained: “y = 3.776x + 0.200”. The regression equation suggested that, on average, a 10-fold increase in viral load would cause a 26% increase in the mortality rate. It can be deduced that a 104-fold increase in viral load would lead to almost 100% patient deaths. Hence, for the first time, we showed a quantitative association between viral load and the mortality rate. Our findings imply that antiviral therapies and anti-inflammatory treatments would be more effective if they are applied in the early stage of infection when the viral load has not reached the high-risk level.