A worker administers a COVID-19 test at a drive through testing site in Texas | Photo by Mario Tama/Getty Images
This week, COVID-19 headlines were split between cautious optimism and abject despair.
On the positive side, Monday morning brought us a scrap of hope — claims from Pfizer and BioNTech that their vaccine candidate was highly effective. Their tests so far showed that it has an efficacy of about 90 percent, though that number could change with time. And before we break out the bubbly, there are still plenty of caveats to the news.
Among the downer highlights: the full data hasn’t been released yet, and this happened in a clinical trial where conditions were more controlled than they will be in the real world. It has to be delivered in two doses, weeks apart, and it’s more fragile than frost on a sunny morning — it has to be stored at…