A doctor performs an injection on a mouse. Photo: D-Keine, via Getty Images
Researchers have developed an antiviral that targets COVID-19 in the body, and which killed off the viral load in infected mice by 99 percent.An international team of scientists from Australia’s Menzies Health Institute Queensland and the United States research institute City of Hope used gene-silencing RNA technology to attack the SARS-CoV2 virus genome directly, binding to it and stopping the virus from replicating and spreading. When comparing the treated mice to the control group, researchers found that SARS-CoV2 was killed off in the former group’s lungs by 99.9 percent.
Professor Kevin Morris, a lead researcher on the study, told VICE World news via email that not only did the researchers see the mice’s condition improve, but following euthanasia and the removal of the animals’ lung tissue – what Professor Morris calls “the true test of the therapy” – they found that they were unable to grow the virus.“This suggests that our treatment substantially repressed the virus in the mice lungs to the point that we can’t grow infectious virus from these lungs,” said Professor Morris. “We can’t grow the virus out of the treated mice lungs, it’s reduced [by] 99 percent … But we are able to grow infectious virus from the control treated mice’s lungs.”He also said that within the first 24 hours they noticed a substantial change in the body weights and demeanours of the treated mice, compared to the control group. “The treatment effects are pretty quick within the first 24 hours,” he said.It is yet to be determined whether the treatment works in humans, but Professor Morris said that if it does, “you would probably treat every two days or so for a week, until the virus is gone and the immune system kicks in to control the viral infection.”Fellow lead researcher Professor Nigel McMillan, from Griffith University, described the antiviral as a “seek and destroy mission.”
"It causes the genome to be destroyed and the virus can't grow anymore – so we inject the nanoparticles and they go and find the virus and destroy it just like a heat-seeking missile," Professor McMillan told the ABC. "This is the first time we have been able to package this up as a particle, send it through the bloodstream to attack the virus.”Professor McMillan further pointed out that while it is "not a cure,” the therapy could reduce the amount of virus in the lungs by 99.9 percent, “so it is almost as good as a cure".“It is really for those people who are suffering for example in ICU, where vaccines are too late,” he said. “This therapy actually stops the virus replicating, so the body can repair itself and the recovery will be much quicker. We basically should be able to eliminate people dying from this disease – if treated soon enough.”In conducting the study, researchers injected lab mice with nanoparticles containing RNA and measured the effect this had on their COVID-19 symptoms. In the paper, the researchers state that “despite several emerging vaccines, there remains no verifiable therapeutic targeted specifically to the [COVID-19] virus. Here we present a highly effective siRNA therapeutic against SARS-CoV-2 infection.”
The implications of this research go far beyond COVID-19, though. Professor Morris pointed out that the therapy would benefit anyone infected with SARS-COV-1 and COV2, but could also potentially be used to treat other coronavirus-related illnesses such as Middle East respiratory syndrome (MERS). The RNA gene-silencing approach, he noted, has been developed to treat not only current but also future iterations of the SARS virus.“The SARS virus will be with us for eternity,” Professor Morris explained. “The evolution of viral resistance is happening and even with vaccines, resistance happens. This therapy is a stop-gate that allows for infected folks to get treatment that targets the virus. The approach is scalable, stable and can be deployed anywhere.”The results are promising, but there is much work still to be done."Whether our approach works in humans remains to be determined, and may never be determined, unless we or someone else can raise the necessary funding and carry out clinical trials,” he added. “But at least we know we can cure COVID-19 in mice.”Follow Gavin on Twitter