When rhesus macaques were given interferon-α2b and ribavirin and exposed to MERS, they developed less pneumonia than control animals. Five critically ill people with MERS in Saudi Arabia with acute respiratory distress syndrome (ARDS) and on ventilators were given interferon-α2b and ribavirin but all ended up dying of the disease. The treatment was started late in their disease (a mean of 19 days after hospital admission) and they had already failed trials of steroids so it remains to be seen whether it may have benefit earlier in the course of disease. Another proposed therapy is inhibition of viral protease or kinase enzymes.