Variants are their dream, but our nightmare. Can we stop them? — What has it felt like for you to hear about a new COVID-19 variant? To take in whether and how it’s different, how and whether it responds to our vaccines, and, ultimately, just how much it’s about to rewind and replay this pandemic. For me, it’s felt like when your airplane takes a sudden dip or a rollercoaster hits the drop, your stomach having…