You’re fully vaccinated against the coronavirus — now what? Don’t expect to shed your mask and get back to normal activities right away.

That’s going to be a disappointment, if not a shock, to many people...

But the Centers for Disease Control and Prevention hasn’t yet changed its guidelines: At least for now, people should follow the same rules as everybody else about wearing a mask, keeping a 6-foot distance and avoiding crowds — even after they’ve gotten their second vaccine dose.

Vaccines in use so far require two doses, and experts say especially don’t let your guard down after the first dose.

“You’re asking a very logical question,” Dr. Anthony Fauci, the top U.S. infectious disease expert, responded when a 91-year-old California woman recently asked if she and her vaccinated friends could resume their mah-jongg games.

In that webcast exchange, Fauci only could point to the CDC’s recommendations, which so far are mum about exceptions for vaccinated people getting together. “Hang on,” he told the woman, saying he expected updates to the guidelines as more people get the coveted shots.

What experts also need to learn: The vaccines are highly effective at preventing symptomatic COVID-19, especially severe illness and death — but no one yet knows how well they block spread of the coronavirus.

It’s great if the vaccine means someone who otherwise would have been hospitalized instead just has the sniffles, or even no symptoms. But “the looming question,” Fauci said during a White House coronavirus response briefing last week, is whether a person infected despite vaccination can still, unwittingly, infect someone else.

Studies are underway to find out, and hints are starting to emerge. Fauci pointed to recent research from Spain showing the more coronavirus an infected person harbors — what’s called the viral load — the more infectious they are. That’s not surprising, as it’s true with other illnesses.

Some preliminary findings from Israel have suggested people infected after the first vaccine dose, when they’re only partially protected, had smaller viral loads than unvaccinated people who got infected. That’s encouraging if the findings hold up. Israel has vaccinated a large fraction of its population and scientists worldwide are watching how the outbreak responds as those inoculations increase.

Also critical is tracking whether the vaccines protect against new, mutated versions of the virus that are spreading rapidly in some countries, added Dr. Walter Orenstein, an infectious disease expert at Emory University. He’s been vaccinated and is scrupulously following the CDC guidelines.

There are practical reasons. “It’s hard to tell who got vaccinated and who didn’t if you’re just walking around the grocery store,” noted University of Pennsylvania immunologist E. John Wherry. ...