It was announced on Monday that Pfizer Inc. (PFE.N) has begun a big study to test its experimental oral antiviral medication to help prevent infection with the COVID-19 virus in people who have been exposed to the virus. Merck & Co Inc. (MRK.N) of the United States and Roche Holding AG (ROG.S) of Switzerland are vying with the drugmaker to create an easy-to-administer antiviral tablet for COVID-19. read on to find out more To test Pfizer’s medicine, PF-07321332, researchers will enrol up to 2,660 healthy adults, 18 and older, who share a residence with a person who has been diagnosed with symptomatic COVID-19 infection. PF-07321332 will be tested in combination with a low dose of ritonavir, an older medicine often used in HIV combination therapy, to limit the function of a crucial enzyme required for the coronavirus to proliferate. The only antiviral medication for COVID-19 now available in the United States is remdesivir, which is available solely by intravenous injection from Gilead Sciences Inc. (GILD.O). In addition, Pfizer has begun a new research with PF-07321332 in symptomatic adult patients who are not in the hospital.. The investigational medicine molnupiravir developed by Merck and Ridgeback Biotherapeutics for the prevention of the COVID-19 infection has recently begun a late-stage trial at Ridgeback. read on to learn more Non-hospitalized people are being tested to evaluate if molnupiravir lessens the risk of hospitalisation or mortality in a late-stage experiment.