Scientists from the United States have developed a drug against COVID-19 based on the RNA hairpin of the virus 
Researchers from the United States reported that the RNA hairpin they developed was SLR14 successfully activates the production of type I interferons in the body (the main instrument of the innate immune response) and protects against coronavirus infection. The article of scientists was published in the Journal of Experimental Medicine.
The first line of defense against SARS-CoV-2 depends on the work of the RIG-I receptors, which recognize the genetic material of the virus and trigger the production of type I interferons – signaling molecules that in turn, contribute to the production of proteins that suppress viral replication. Interferon therapy has been shown to be effective in reducing mortality from COVID-19, but remains very expensive.
Researchers at Yale School of Medicine have proposed a cheaper alternative: giving patients hairpins – elements of the secondary structure of RNA – that mimic the genetic material of SARS- CoV-2 and activate RIG-I receptors. Scientists have tested their new treatment approach in mice infected with COVID-19. A single dose of SLR14 was sufficient to protect rodents from severe disease and death. When administered immediately after infection, the therapy turned out to be even more effective than treatment with interferons.
Moreover, SLR14 also protected against new variants of the coronavirus, including the delta variant. In mice with weakened immunity, the drug was able to almost completely cleanse the body of the virus. According to the researchers, this will allow them to treat patients with weakened immune systems, the effectiveness of existing vaccines for which is greatly reduced.