(NerdWallet) — The thrill of receiving a COVID-19 vaccine is giving way to apprehension for many would-be summer travelers, as uncertainty continues to swirl concerning when, whether and where to travel internationally.

One of the biggest areas of confusion surrounds so-called vaccine passports, which would grant travel and other freedoms to fully vaccinated people. Although everyone on social media seems to have an opinion about vaccine passports, actual facts about them remain thin.

The truth is, we know very little about vaccine passports or how proof of vaccination will affect international travel. Despite a widespread need to verify vaccination status, few clear plans for how to carry out this task have come to light. Still, there are a few things that vaccinated travelers should know at this stage.

Key takeaways:

• You’ll need to prove your vaccination status to travel to many countries.
• It’s not yet clear how this verification process will work.
• Your paper vaccine card might be good enough.

Many destinations will require proof of vaccination

The European Union will ease restrictions for vaccinated U.S. travelers by late June, according to a proposal from the European Commission. And while the proposal touts the EU’s “Digital Green Certificate” vaccine passport, it concedes that, “Member States should be able to accept certificates from non-EU countries based on national law.”

It also suggests that a portal will be available where travelers can submit vaccine documentation from their home country as proof or be issued a Digital Green Certificate. But these plans are hardly set in stone, and summer is fast approaching.

It seems that many countries will follow Europe’s lead and open to vaccinated tourists soon. We just don’t yet know which apps and verification processes will be used by each country. As the recent EU proposal indicates, your vaccine card may be proof enough.

What does this mean for you? Keep your completed vaccine card in a safe place (you might take a picture of it to be extra safe). And don’t worry yet about trying to learn how or whether to get a particular vaccine passport.

The U.S. government won’t be involved

One thing is clear at this point: The federal government won’t be managing vaccination verification.

“Unlike other parts of the world, the government here is not viewing its role as the place to create a passport, nor a place to hold the data of citizens,” said Andy Slavitt, the White House’s senior adviser for COVID-19 response, at a press briefing.

It will be up to individual states or private companies to develop vaccination certification programs. This could mean that no single program becomes the gold standard for tourism. Instead, several independent services will likely provide vaccine verification for tourists.

The apps are coming, but are they necessary?

Several organizations have announced plans for digital apps to verify vaccination status, with names like Health Pass and CommonPass, though none is available yet.

How will these apps work? We’re not sure. Clear, the airport security company behind Health Pass, says on its website: “After you have received the COVID-19 vaccine, simply link to your healthcare account to confirm your vaccine records in a secure, verifiable and privacy-preserving way.”

Sounds simple, but given the disparate systems and pharmacies involved in distributing the vaccine, it seems unlikely to be so. How these apps could do much more than verify a picture of your paper vaccine card remains cloudy. Clear didn’t respond to our request for more information.

Our guess? You’ll use your vaccine card to verify your status for at least the next few months. More elaborate systems might emerge later, but not in time for summer travel.

The bottom line

You’ll need to prove that you’ve been vaccinated to travel to many countries this summer, but how you’ll do that remains somewhat of a mystery. With the federal government not driving a universal vaccine passport program, it’s up to states and other organizations to fill the gap. Simply put, that’s unlikely to happen before summer.

Our advice is to keep your paper vaccine card handy and wait for the chips to fall. If you’re planning to book travel to a particular country, do your research and see what restrictions and expectations are in place ahead of time.

Sam Kemmis writes for NerdWallet. Email: skemmis@nerdwallet.com. Twitter: @samsambutdif.

The article Vaccine Passports and Summer Travel: What We Know originally appeared on NerdWallet.