Remdesivir and hydroxychloroquine, two drugs being commonly used to treat Covid, had little or no effect on patients' length of hospital stay or chances of survival, a WHO trial has found. news agency Reuters has reported. Antiviral drug Remdesivir, among the first to be used as a treatment for Covid-19, was one of the drugs recently used to treat US President Donald Trump's coronavirus infection. The WHO evaluated the effects of four potential drug regimens, including remdesivir, hydroxychloroquine, anti-HIV drug combination lopinavir/ritonavir and interferon, in 11,266 adult patients across more than 30 countries. The study found the regimens appeared to have little or no effect on 28-day mortality or the length of the in-hospital stay, the WHO said on Thursday.