‘ve just had my second dose of the vaccine, and now I have a vaccine card. Um, what do I do with it?

That’s a good question. The U.S. version bears this instruction: “Bring this vaccine record to every vaccination or medical visit.”

In essence, it’s proof that you’ve gotten the jab (or jabs for the two-dose options).

Beyond that? Yes, there are questions about what purpose it can serve — and how to safeguard it.

In the U.S., the card is a 3 by 4 inches. The document will have your name, birthdate and key information about your vaccine regimen: which brand you got, when you received your dose or doses, and where you were inoculated.

The idea of giving out cards to document a vaccination has been around since the 1930s, says Maureen Miller, an adjunct associate professor of epidemiology at Columbia University’s Mailman School of Public Health.

“As people colonized the world, there were illnesses that were endemic to certain areas,” she says. “Using cards saw to it that those diseases could be monitored as individuals crossed borders, like the now internationally recognized yellow fever vaccine cards.”

Indeed, the COVID-19 Vaccination Record Card is a valuable document. Dr. Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security, “urges people to keep [vaccine cards] safe.” So-called vaccine passports will likely soon be needed for some international travel, he says — though the concept is still very much in the development stage. One idea is to digitize immunization records into easy-to-trace systems such as scannable bar codes. Until those systems get set up though, you’ll likely need to carry your physical card for international travel — even though its size in the U.S., for example, isn’t the most wallet-friendly.

The use of the vaccine card may stretch far past air travel, Miller says. You may need it to enter movie theaters, board trains, even sometimes as a condition of employment. In the U.K., for instance, government officials are considering asking individuals to present proof of vaccination to get access to public spaces such as pubs and sporting events — a provision that reportedly more than 70 lawmakers have announced they’ll oppose.

As societies begin to reintegrate and have similar conversations, having a vaccine card will likely determine access to certain services. To this end, “people should be guarding vaccine cards very carefully,” Miller says.

So what does that mean for you once you receive your vaccine card?

First things first. Miller says it’s prudent to take pictures of both sides of your document as soon as you receive it or find a way to scan it, just so you have a personal record. That’s what people often do with a driver’s license or passport, she notes. While it wouldn’t fly to present a phone scan as proof of vaccination, it’s good to capture all the data just in case you lose your card.

(A quick tip for iPhone users is to use the built-in Notes app for a close-to-Xerox-looking clean photocopy.)

Miller also suggests laminating your card, as she did. That way, the card feels a bit less like a random scrap of paper and more like the real, official and important document it is. But some worry that lamination might preclude the ability to update a card with potential immunity “boosters” in the future. Adalja says thinking about “boosters” is a bit premature and urges individuals to do what works for them. And if you opt for lamination, you shouldn’t have difficulty fulfilling that goal. Office supply stores such as Staples, Office Depot and OfficeMax have agreed to laminate, for free, your vaccine card if you visit one of their stores. Check to make sure the offer is still on before stopping by.

As to where you’d keep the card at home, Miller says she has hers in the folder she uses for medical insurance and health documents. A safe bet would be anywhere you store important records such as passports. Miller emphasizes it’s probably better to keep it at home and not in a security deposit box in a bank.

And in the worst-case scenario, what if you lose your card?

“The physical document isn’t the only record,” Adalja says.

When you get vaccinated, that information enters your state’s immunization registry, Adalja says – so no need to call up your primary care doctor or do any other logistical legwork to make it be part of your permanent health record. That process should happen automatically (although it couldn’t hurt to call your primary care doctor just to make sure it did).

In the case of losing your card, your best bet is to hit up the pharmacy or clinic or site where you got your vaccine at and ask for a duplicate copy. This will be problematic if you were vaccinated at a local pop-up effort; in that case, Miller suggests contacting your state board of health. You should be able to get a duplicate, but perhaps not without a fair share of moving through bureaucracy, Adalja says.

Eventually, Adalja predicts, more “durable forms of vaccination status” — aka, records that don’t just exist on a flimsy piece of cardstock — will emerge. But until then, it’s just a matter of being extra careful.

My choir director says that the pandemic is ending soon and that face-to-face, in-person practice is expected to begin in May. Is it true that vaccinated people can safely sing together? Should people still be wearing masks?

Singing indoors is one of the riskiest things you can do during this pandemic — up there with screaming for your March Madness picks in a packed arena. When you sing or scream, you expel air forcefully, which generates lots of respiratory aerosols that can contain SARS-CoV-2, the virus that causes COVID-19.

We all remember that haunting episode from the early days of the pandemic in which 52 of 61 members at a choir rehearsal in Skagit County, Wash., got confirmed or probable cases of COVID-19 after a 2 1/2-hour practice. Three choir members were hospitalized, and two died.

But the vaccines are powerful tools. So, for advice, we tapped one of the co-authors of the International Coalition of Performing Arts Aerosol Study, University of Maryland mechanical engineering professor Jelena Srebric, and Dr. Jill Weatherhead, assistant professor of adult and pediatric infectious diseases at Baylor College of Medicine.