Researchers at universities and pharmaceutical companies are rushing to identify drugs that might help cut the number of deaths from Covid-19 and take the strain of hospitals. Justin Rowlatt speaks to Richard Marsden, the chief executive of one such company, Synairgen. He hopes that a medicine his company originally developed to help asthma and flu sufferers could also now be put to use in alleviating the lung infections of Covid-19 patients. Meanwhile virologist Stephen Griffin of Leeds University in the UK explains the three main ways in which existing drugs might be used to attack the virus. Plus Theodora Bloom of the British Medical Journal tells Justin about her night job at the online research sharing server MedRxiv, which has played a central role in helping researchers get immediate access to each other's work, accelerating their response to the pandemic. (Picture: Medical worker wearing protective gear treats a patient infected with the Covid-19 at the intensive care unit in Prague; Credit: Gabriel Kuchta/Getty Images)