A surge in COVID-19 infections has swept the country this summer, upending travel plans and bringing fevers, coughs and general malaise. It shows no immediate sign of slowing. While most of the country and the federal government has put the pandemic in the rearview mirror, the virus is mutating and new variants emerging. Even though the Centers for Disease Control and Prevention (CDC) no longer tracks individual infection numbers, experts think it could be the biggest summer wave yet. So far, the variants haven’t been proven to cause a more serious illness, and vaccines remain effective, but there’s no certainty...