The authors of a study, published September 8 in the journal Proceedings of the National Academy of Sciences, contend that this new therapy -- a therapeutic interfering particle (TIP) -- is the only single-dose antiviral that reduces not only symptoms and severity of COVID-19, but also shedding of the virus.

The researchers treated hamsters infected with SARS-CoV-2 with the antiviral TIPs and took daily measurements of the amount of virus in the rodents' noses. By the fifth day, all of the animals in the control group were still shedding high levels of virus, while the virus was undetectable in four out of five of the TIP-treated hamsters.

Rather than directly targeting a portion of a virus, TIPs compete for resources in an infected cell by hogging its internal replication machinery and keeping the virus from generating more copies of itself. In addition, because TIPs reside inside the same cells as the virus they target, the therapy evolves with the virus and stays active even as new viral strains emerge.

"Historically, it has been exceptionally challenging for antivirals and vaccines to limit the transmission of respiratory viruses, including SARS-CoV-2," says Gladstone Senior Investigator Leor Weinberger, PhD, senior author of the new paper. "This study shows that a single, intranasal dose of TIPs reduces the amount of virus transmitted and protects animals that came into contact with that treated animal."

Researchers are now seeking approval from the U.S. Food and Drug Administration for a clinical trial to test the TIPs in humans.