Commentary Many millions of these rapid antigen tests at a cost of billions of dollars are now in most homes. The federal government and many local organizations have been making them available without charge. But newly published research from the UK sheds a dark shadow on their usefulness. The initial hope was that making rapid home tests widely available would help curb COVID-19 transmission, and probably some officials thought they would motivate more people to get COVID-19 vaccine shots if people tested positive. The other, perhaps, bigger hope was that if people tested negative, they could feel safe that they didn’t have COVID-19 infection and could lead normal lives. They wouldn’t be transmitting the virus. This was especially the hope if people didn’t have symptoms. They would be home free. And with lots of free home test kits widely available, people could test frequently to keep feeling safe for themselves …