CD274 and infection: The median NPX value of CXCL10—a chemokine associated with viral infections and interferon responses—was significantly lower in the SARS‐CoV‐2‐positive group, but this reduction was absent when BCG had been administered prior to infection; in addition, the median NPX value was higher for soluble PD‐L1 (a checkpoint‐protein related to T‐cell activation) (Figure 2d and e).