It was the first time in months that I saw a medical doctor smiling on TV while talking about the corona virus. The news had just broken that Pfizer's COVID-19 vaccine may be 90% effective. In a world desperate to bring the deadly outbreak under control, this was "hope in a bottle," as the doctor put it. And then today, just as I was about to write this devotion, another company, Moderna, reported that their vaccine, at 94%, had been tested as even…