COVID-19
A study from a British company called Synairgen showed that some patients with mild COVID-19 who took interferon beta were less likely to develop severe COVID-19, and they got better faster.  The doctors gave the patients interferon beta by letting them breathe in a spray. The study was performed on 101 patients, which is not many.  The scientists gave some patients interferon beta and other patients a placebo, a harmless but empty spray.  The COVID-19 patients who received the real medicine were 79% less likely to develop a severe case.  As of July 2020, scientists are planning to test inhaled interferon beta in a larger study with 400 patients to see if it really does help.