A protein called CD47 that helps damaged cells avoid destruction by the immune system may be contributing to severe cases of Covid-19, researchers believe. In another study, Gilead Sciences Inc’s intravenous antiviral drug remdesivir helped keep high-risk Covid-19 patients out of the hospital in a randomized trial.

Pfizer Inc. started a large study testing the company’s investigational oral antiviral drug for the prevention of Covid-19 infection among those who have been exposed to the virus.

Drugmaker Merck & Co. Inc. sees potential U.S. emergency use authorization for the company’s experimental Covid-19 antiviral treatment, molnupiravir, before year-end 2021.

The Bill & Melinda Gates Foundation will make a $35 million equity investment in privately owned Exscientia Ltd. to fund the development of antiviral drugs including for the coronavirus, the Oxford-based drug developer said on Sept. 8.

Pfizer Inc. started dosing in a mid-to-late-stage trial of the company’s oral antiviral therapy for Covid-19 in non-hospitalized, symptomatic adult patients.

Merck & Co. and partner Ridgeback Biotherapeutics said on Wednesday they had begun enrolling patients in a late-stage trial of their experimental drug molnupiravir for the prevention of Covid-19 infection.

An antiviral treatment under development by Atea Pharmaceuticals is showing promise against Covid-19.

Eli Lilly and Co. and partner Incyte Corp. said on Aug. 3 additional results from a late-stage study showed their Covid-19 drug baricitinib reduced the risk of death in patients on mechanical ventilation.

The U.S. health regulator expanded the emergency use authorization for Eli Lilly’s baricitinib for Covid-19, saying the arthritis medicine could now be used without taking Gilead’s drug remdesivir along with the product.

Gilead Sciences Inc. said an analysis showed the company’s antiviral remdesivir reduced mortality rates in hospitalized patients with Covid-19 and increased the likelihood of being discharged by day 28 after a five-day course of the treatment.