New York, April 18 : An experimental oral antiviral drug has shown potential in prevention and treatment of SARS-CoV-2, the virus causing Covid-19 infections, say researchers. The antiviral -- MK-4482 -- significantly decreased levels of virus and disease damage in the lungs of hamsters treated for SARS-CoV-2 infection, according to a new study from the US National Institutes of Health scientists. MK-4482 is currently undergoing human clinical trials. In the study, published in the journal Nature Communications, the scientists found MK-4482 treatment effective when provided up to 12 hours before or 12 hours after infecting the hamsters with SARS-CoV-2. MK-4482 treatment potentially could mitigate high-risk exposures to SARS-CoV-2, and might be used to treat established SARS-CoV-2 infection alone or possibly in combination with other agents, said Heinz Feldmann and team from the NIH. The project involved three groups of hamsters: a pre-infection treatment group; a post-infection treatment group; and an untreated control group. For the two treatment groups, scientists administered MK-4482 orally every 12 hours for three days. At the end of the study, the animals in each of the treatment groups had 100 times less infectious virus in their lungs than the control group. Animals in the two treatment groups also had significantly fewer lesions in the lungs than the control group. The scientists determined the MK-4482 treatment doses for this study based on previous experiments performed in mouse models of SARS-CoV-1 and MERS-CoV. In those studies, MK-4482 was effective at stopping the viruses from replicating. Emory University's Drug Innovation Ventures group in Atlanta developed MK-4482 (also known as molnupiravir and EIDD-2801) to treat influenza. MK-4482 is being developed by biotechnology firm Ridgeback Biotherapeutics in collaboration with Merck as a potential Covid-19 treatment. The drug is in Phase 2 and 3 human clinical studies. /IANS