THERE is still no perfect COVID-19 cure that can significantly cut the risk of transmission — and there are no over-the-counter drugs that would allow patients to treat the illness at home. Doctors are trying several novel therapies in tests, and now a team of scientists from Germany and the U.K. think they’ve found another drug that can effectively block the replication of SARS-Cov-2 inside the body. After it gains access to the body, the coronavirus infects cells. The pathogen hooks up to the ACE2 receptor to penetrate the cell membrane. Once inside the cell, it takes over and creates thousands of copies of itself. The host cell is killed in the process, and the new SARS-CoV-2 replicas attack other cells. As that happens, the immune system takes measures to kill the pathogen and get rid of infected tissue. As the viral load increases inside the body, patients can start experiencing symptoms, including severe ones. These people are also contagious to others. The immune system can mount a defense of varying strength. Some people clear the virus faster, and their condition ameliorates as symptoms subside. Others worsen in a matter of days and risk death. A team of German and British researchers conducted experiments with aprotinin, a protease inhibitor that can block the virus from entering cells. The antiviral activity of the drug would help reduce the SARS-CoV-2 viral load and improve a patient’s COVID-19 prognosis. The scientists say that the drug may work best if given early after a COVID-19 infection. Aprotinin “may be if limited in late-stage COVID-19 disease.” At that point, it’s the exacerbation of the immune response that needs to be stopped rather than viral replication. “The main potential of antiviral drugs may lie in the early treatment of COVID-19 patients to suppress virus replication and, through this, to prevent COVID-19 progression into a severe, life-threatening disease,” the researchers write. “Local aprotinin therapy of the airways and the lungs using an aerosol, which is clinically approved in Russia and has been reported to be very well tolerated in influenza patients, may have particular potential as such an antiviral treatment for early-stage COVID-19 disease. “Notably, aprotinin may additionally prevent the very early stages of lung injury by inhibition of matrix metalloproteinases and, in turn, of the cytokine storm that eventually results in severe, systemic COVID-19 disease.” (SD-Agencies) | 