Potential COVID-19 antiviral drug being tested in humans after proving effective in hamster study

A potential COVID-19 antiviral drug is showing early promise and effectiveness in hamsters, according to a new study from the National Institutes of Health.

Results revealed that the experimental antiviral drug MK-4482 "significantly decreased levels of virus and disease damage in the lungs of hamsters treated for SARS-CoV-2 infection," according to a statement.

The experimental drug, delivered only orally, is now being tested in human clinical trials by Ridgeback Biotherapeutics and pharmaceutical company Merck. Remdesivir, a different antiviral drug already approved by the U.S. Food and Drug Administration, can only be provided intravenously.

Scientists said they found MK-4482 proved to be effective when given up to 12 hours before, or 12 hours after, the hamsters were injected with the coronavirus. 

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The latest study 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 gave the hamsters MK-4482 orally every 12 hours for three days. Results showed the hamsters had 100 times less infectious virus in their lungs than the control group and had fewer lesions in the lungs than the control group.

The U.S. Food and Drug Administration has only fully approved Remdesivir, an antiviral agent, for COVID-19 treatment. It is recommended for patients in a hospital who require supplemental oxygen. In addition, the agency has granted emergency use authorization for nine other COVID-19 treatments.

RELATED: Global COVID-19 death toll passes 3 million people

The drugs approved for emergency use, delivered intravenously and made by Regeneron Pharmaceuticals and Eli Lily, have concentrated doses of lab-made antibodies to fight COVID-19 and are geared toward people who are at high risk for severe symptoms or having to be hospitalized.

Michigan will expand its use of COVID-19 treatment in the hopes of substantially reducing its rising numbers of hospitalizations and deaths, state officials announced last week amid their efforts to bring down the nation’s highest infection rate.

Gov. Gretchen Whitmer said the Remdesivir treatment could save lives, adding that it "very likely" helped then-President Donald Trump when he was infected last fall. People who qualify — an estimated 30% of infected residents — include seniors and those with preexisting or underlying health risks.

According to Johns Hopkins, more than 31 million Americans have tested positive for COVID-19 since the pandemic began in March 2020. Since then, more than 567,000 Americans have died from the virus.

RELATED: Half of US adults have now received at least one shot of COVID-19 vaccine, CDC says

Half of all adults in the U.S. have received at least one COVID-19 shot, the government announced Sunday, marking another milestone in the nation’s largest-ever vaccination campaign but leaving more work to do to convince skeptical Americans to roll up their sleeves.

Almost 130 million people 18 or older have received at least one dose of a vaccine, or 50.4% of the total adult population, the Centers for Disease Control and Prevention reported. Almost 84 million adults, or about 32.5% of the population, have been fully vaccinated.

The Associated Press and Megan Ziegler contributed to this report. This story was reported from Los Angeles.