Actemra does not directly target the SARS-COV-2 virus (the virus that causes COVID-19), rather it reduces inflammation by blocking the interleukin-6 receptor, which is on interleukin-6, one of the main proinflammatory cytokines (these are cell-to-cell signaling proteins that stimulate an immune response). In some cases of COVID-19 infection, the immune system can become hyperactive, which may result in worsening disease.