Due to the increased levels of cytokines and interferons in those with severe Sars-CoV-2, both are being investigated as potential therapies for COVID-19. An animal study done on mice found that those producing early strong interferon responses to SARS-CoV, which also originated from bats, were more likely to live, while other cases were likely to experience a highly morbid overactive immune system. The high mortality rate of COVID-19 in older populations were linked to the impact of age on interferon responses.