The race to develop a vaccine began soon after the discovery of the virus and is continuing. Picture: Henk Kruger, ANA.
With a looming third wave of Covid-19 in South Africa and even a fourth wave elsewhere in the world, scientists around the world are working hard to find and develop treatments for the destructive coronavirus.
Since the discovery of the virus in Wuhan in December 2019 there have been more than 165 million cases of Covid-19 across the world, resulting in 3.4 million deaths.
Off-label drugs modestly effective
Until now, the drugs used in the treatment of Covid-19 that were originally used for other purposes (“off-label” use), such as dexamethasone (a glucocorticoid used for rheumatism, asthma, chronic obstructive lung disease), remdesivir (a broad-spectrum antiviral drug to treat Ebola), hydroxychloroquine (to treat malaria), lopinavir and ritonavir (to treat HIV), favilavir (to treat inflammation in the nose and throat), molnupiravir (originally used for flu), heparin/enoxaparin (anticoagulants), and ivermectin (veterinary medication for parasite infestations) have proved to be at most modestly effective against Covid-19 and did not always provide any substantial benefit to recovery.
New experimental medications not hugely effective
Although helpful in mild and non-hospitalised cases, most of the newly developed experimental medications such as casirivimab/imdevimab and bamlanivimab/etesivimab (monoclonal antibody treatments) have not been hugely effective in preventing illness or treating the symptoms of Covid-19 in more severe cases.
Effectiveness of some vaccines limited by variants
The race to develop a vaccine began soon after the discovery of the virus and is continuing. Unfortunately, the emergence of new viral variants has demonstrated the limited effectiveness of some of the current vaccines to these variants and thus increased the need for specific therapies to treat Covid-19 infections.
New treatment for Covid-19
However, on May 13 it was announced in the journal Molecular Therapy that an international team of scientists from the Menzies Health Institute Queensland (MHIQ) at Griffith University in Australia and the City of Hope in the US has developed a novel experimental direct-acting antiviral therapy to treat Covid-19.
Antiviral treatment is not new and has been widely used to reduce symptoms and help people recover faster from Covid-19. Unfortunately, none of these treatments could directly stop the virus as it grows in a patient’s lungs.
Gene-silencing technology destroys Covid-19
However, scientists have now developed a next-generation antiviral approach by using gene-silencing RNA technology called siRNA (small-interfering RNA) to attack the virus’ genome directly, almost like a “heat-seeking missile”. This seek-and-destroy treatment with virus-specific siRNA prevents the virus from replicating by fitting like a jigsaw piece directly into the viral genome. When it does so, it gives off a signal for the cell to destroy that genetic material, rendering the viral particles inert. The treatment destroyed 99.9% of Covid particles in the lungs of mice during trials and improved their survival rate remarkably.
Virus particles are basically packets of information on how to make more viruses encoded in a molecule, called ribonucleic acid or RNA. The best way, therefore, to stop a virus is to stop its RNA information being copied and transcribed to the human cell.
The Pfizer and Moderna Covid-19 vaccines that are effective in blocking the disease also use modified RNA. But while vaccines focus on the prevention of infection by the virus, the new therapy is aimed at people who are already severely ill with Covid-19.
Delivered to the lungs by stealth lipid nanoparticles
Lipid nanoparticles that were designed by Griffith University and City of Hope scientists are used to deliver the siRNA to the lungs, the critical site of infection. The lipid (fat-like) particles provide a protective coating, without which the siRNA would be destroyed in the bloodstream. These stealth nanoparticles can be delivered to a wide range of cells in the lungs where they bind to the genome of the virus to silence the viral genes.
Treats all variants
And the wonderful news is that the treatment works on all betacoronaviruses and any new variants that may arise in the future because the treatment targets ultra-conserved regions in the virus’s genome directly.
According to Prof Nigel McMillan, the co-lead researcher, although the treatment is not a “cure”, the therapy could possibly put a stop to Covid-related deaths across the world by reducing the amount of the virus in the lungs, which is “almost as good as a cure”.
Possibly available in 2023
Although normal cells are completely unharmed by the treatment and the results are very promising, the effectiveness of the treatment has only been tested in rodents. The researchers hope that the treatment will be ready in 2023, depending on the success of the next phase of clinical trials in humans.
Although 2023 is still some time away, this breakthrough is good news since it seems that the virus is not going away any time soon. In fact, we are going to be living with it forever. Hopefully our scientists will achieve success in their global pursuit of scientific miracles in the fight against the devastating Covid-19.
Professor Louis C H Fourie is a technology strategist.
*The views expressed here are not necessarily those of IOL or of title sites.