At long last, we have made a truly game-changing scientific breakthrough in preventing the spread of COVID-19. The impact of this breakthrough seems almost too good to be true. We have found a disease control tool that, when used properly, can dramatically reduce the person-to-person transmission of SARS-CoV-2, the virus that causes COVID-19. Studies have shown that this tool could reduce transmission by somewhere between 50% and 85%. The tool is cheap and remarkably low-tech.