When can we start safely doing normal things, like going to the movies or the theater?

Public health officials estimate that 70 to 75 percent of the population needs to be vaccinated before people can start moving freely in society again. If things go well, life could get a lot better by late spring and early summer. “It depends on the uptake of the vaccine and the level of infection in the community,” Dr. Fauci said.

Given the surveys so far showing significant public reluctance to get vaccinated, however, it may take awhile to see widespread community protection, he said: “If it turns out that only 50 percent get vaccinated, then it’s going to take much, much longer to get back to the kind of normality that we’d like to see.” —Tara Parker-Pope
Will these vaccines put a dent in the epidemic?

The coronavirus vaccines will be much less effective at preventing death and illness in 2021 if they are introduced into a population where the virus is raging — as is now the case in the U.S. A vaccine that’s 95 percent effective, as Moderna’s and Pfizer’s versions appear to be, is a powerful fire hose. But the size of a fire is still a bigger determinant of how much destruction occurs.

According to the authors of a paper in the journal Health Affairs, at the current level of infection in the U.S. (about 200,000 confirmed new infections per day), a vaccine that is 95 percent effective — distributed at the expected pace — would still not be enough to end the terrible toll of the virus in the six months after it was introduced. Almost 10 million or so Americans would contract the virus, and more than 160,000 would die.

Measures that reduce the virus’s spread — like mask-wearing, social distancing and rapid-result testing — can still have profound effects. Public health officials hope that people will continue to take these precautions at least until the country reaches a vaccination rate of 70 to 75 percent. —David Leonhardt
Will I be required to provide proof of vaccination to travel?

In the coming weeks, major airlines including United, JetBlue and Lufthansa plan to introduce a health passport app, called CommonPass, that aims to verify passengers’ coronavirus test results — and perhaps soon, vaccinations. CommonPass notifies users of local travel rules — like having to provide proof of a negative virus test — and then aims to check that they have met them.

Although no plans are in place yet to require proof of vaccination for travel or other activities, electronic vaccination credentials could have a profound effect on efforts to control the virus and restore the economy. They could prompt more employers and college campuses to reopen. And developers say they may also give some consumers peace of mind by creating an easy way for movie theaters, cruise ships and sports arenas to admit only those with documented virus vaccinations. Read the full story. —Natasha Singer
How long will the vaccine last? Will I need another one next year?

That is to be determined. It’s possible that coronavirus vaccinations will become an annual event, just like the flu shot. Or it may be that the benefits of the vaccine last longer than a year. We have to wait to see how durable the protection from the vaccines is. Immunity from coronavirus infections appears to last for months, at least, so that may be a hint about vaccines. —Carl Zimmer The New York Times