In the U.S., all eyes are on Pfizer and Moderna. The topline efficacy results from their experimental COVID-19 vaccine trials are astounding at first glance. Pfizer says it recorded 170 COVID-19 cases (in 44,000 volunteers), with a remarkable split: 162 in the placebo group versus 8 in the vaccine group. Meanwhile Moderna says 95 of 30,000 volunteers in its ongoing trial got COVID-19: 90 on placebo versus 5 receiving the vaccine, leading both companies to claim around 95% efficacy.

Let’s put this in perspective. First, a relative risk reduction is being reported, not absolute risk reduction, which appears to be less than 1%.Second, these results refer to the trials’ primary endpoint of COVID-19 of essentially any severity, and…