Each week, we answer “frequently asked questions” about life during the coronavirus crisis. If you have a question you’d like us to consider for a future post, email us at goatsandsoda@npr.org with the subject line: “Weekly Coronavirus Questions.”

I have started hearing that vaccine recipients should abstain from alcohol between the first and second doses of the COVID vaccine. Is this a thing?

It’s true that chronic, heavy drinking and binge drinking can suppress your immune system, says Richard Kennedy, professor of medicine at the Mayo Clinic in Rochester, Minn., and co-director of the Vaccine Research Group. And there are plenty of health reasons not to drink alcohol, he adds. But an occasional drink here and there — including a celebratory toast after your second shot? “That won’t have an effect,” he says.

What, exactly, does it mean that a vaccine is, for example, 92% efficacious? Does it mean there’s an 8% chance of my getting COVID-19? If so, why would anyone want to get a vaccine that’s only 60 or 65% efficacious?

I find the subject of vaccine efficacy very confusing!

Don’t worry: If you find it confusing, you’re probably on the right track! Efficacy rates (and effectiveness rates and point estimates and confidence intervals) should appear at least a little confusing to most non-biostatisticians. The concepts rely on statistical thinking that many aren’t familiar with, says Brianne Barker, a virologist at Drew University.