RNA based therapy may protect from many Covid variants, says study

These molecules recognise the virus’s genetic material and induce the production of signalling proteins known as type I interferons. These interferons promote the production of proteins that can inhibit viral reproduction and stimulate the recruitment of immune cells to fight the infection, the researchers said.

Multiple studies have suggested that early and robust production of interferons protects against COVID-19, whereas delayed production is associated with severe disease. A clinical trial has shown that treating COVID-19 patients with purified interferon protein early during disease can reduce mortality, but manufacturing interferons is extremely expensive.

The latest study suggests a cheaper option in the form of short RNA molecules that mimic SARS-CoV-2’s genetic material and activate the RIG-I receptor to stimulate production of type I interferons by the body’s own cells. The researchers tested their approach in mice susceptible to SARS-CoV-2 infection.

A single dose of an RNA molecule named SLR14 was sufficient to protect the mice from severe disease and death, particularly if the treatment was provided shortly before or soon after exposure to the virus, the researchers said.

When administered shortly after viral infection, SLR14 was more effective than treating mice with purified interferon protein, they said. SLR14 protected mice from all emerging SARS-CoV-2 variants, including Delta.

The researchers tested SLR14 in immunocompromised mice chronically infected with SARS-CoV-2. The RNA molecule was able to completely clear the virus from these animals, even though they lack both T cells and antibody-producing B cells.

The researchers noted that RNA molecules like SLR14 are relatively cheap and easy to manufacture. “SLR14 therefore holds great promise as a new class of RNA therapeutics that can be applied as antivirals against SARS-CoV-2, Iwasaki added.