When Should You Get A COVID-19 Test Once You're Vaccinated?

Is a test necessary after a coronavirus exposure? What about when you travel or visit someone? Follow this guide.
Experts explain when it's necessary to get a coronavirus rapid or PCR test once you're vaccinated and when it's OK to skip.
Experts explain when it's necessary to get a coronavirus rapid or PCR test once you're vaccinated and when it's OK to skip.

Throughout the pandemic, health officials have advised us that one of the best ways to blunt the spread of COVID-19 is to test early and test often.

We’ve been encouraged to get tested after being exposed to someone with confirmed or suspected COVID-19. We got tested during quarantines, before and after travel, and leading up to interactions with others.

But the role of testing changes drastically for people who’ve been vaccinated, and many are left wondering: Is this type of testing still necessary after receiving the shot?

In general, vaccinated people don’t need to get tested unless they have symptoms of COVID-19. The chance of contracting the coronavirus after being fully vaccinated is very rare. Furthermore, positive tests in vaccinated people who are asymptomatic could be misleading — viral loads in people with breakthrough infections tend to be very low, which suggests they probably aren’t contagious.

Still, given all the uncertainty, some infectious disease doctors say there may be certain situations in which a vaccinated person will want to go ahead and get tested.

Here’s what to know about getting tested after you’ve been vaccinated:

Get tested if you have symptoms.

“The only time you should be tested after being fully vaccinated against COVID is if you develop symptoms consistent with COVID,” said Amesh Adalja, a senior scholar at the Johns Hopkins University Center for Health Security in Baltimore and an infectious disease expert. This includes a fever, cough, shortness of breath and muscle aches or chills.

This is consistent with the latest guidance from the U.S. Centers for Disease Control and Prevention. Even if you were directly exposed to someone with COVID, you don’t need to get tested as long as you don’t have symptoms, according to the guidelines.

And get a test if it’s required for travel or entry somewhere.

You can now travel domestically without worrying about testing and quarantining, but if you plan to travel internationally, you may have to take a pre-entry test and then another a few days before flying back to the U.S. There may also be certain businesses, cruises or entertainment venues that require customers to get tested, in which case, go ahead and take it.

People living or working in congregate settings may also need to abide by stricter testing rules.

You don’t need to get tested if you were exposed.

It’s pretty unlikely that a vaccinated person will become infected and extremely rare they’d be hospitalized or die. Recent data shows the risk of getting infected after vaccination is 0.008% (which includes asymptomatic and mild cases).

Even if a vaccinated person were to get infected, the chances of them transmitting it to others is slim. Multiple studies have shown that vaccinated people with breakthrough infections have very low viral loads that are “not necessarily likely to be contagious to others,” Adalja said.

Data suggests that the higher a person’s viral load is, the more infectious they are. Because of all this evidence, vaccinated people who were exposed to someone with COVID-19 but don’t have symptoms are no longer required to get tested.

According to Adalja, there’s also a chance a positive polymerase chain reaction (PCR) test in symptomless vaccinated people could be misleading. PCR tests are sensitive and can pick up on small amounts of the coronavirus in vaccinated people who might be clearing out the virus but aren’t infectious.

Some experts recommend going for a rapid antigen test, which is less sensitive than a PCR test, if you’ve been vaccinated. “I would recommend an antigen test and if it is negative stop [getting tested]. A positive antigen test should be followed by a PCR test to make sure that the antigen test is not a false positive, which it likely could be in a fully vaccinated person,” Adalja said.

If the PCR test also comes back positive, it could be a breakthrough infection. Adalja recommends talking to your doctor and having the sample sequenced to see if it’s a variant of the virus.

Your risk of a COVID-19 infection is very low once you're vaccinated.
Your risk of a COVID-19 infection is very low once you're vaccinated.

There may be other special cases in which a test might make sense.

Though vaccinated people are well protected against COVID-19, there may be certain situations in which a test might be warranted — i.e., if you were knowingly exposed to someone with COVID-19 and plan to visit a high-risk relative or unvaccinated friend.

The vaccines, though incredibly effective, aren’t 100%, and there will be rare breakthrough infections, said Anne Liu, an infectious disease physician at Stanford Health Care in Palo Alto, California. In general, vaccinated people shouldn’t be discouraged from getting tested. Getting tested in these sorts of gray-area situations isn’t required, but it might be the most prudent thing to do, according to Liu.

Some elderly and immunocompromised people might not respond well to the vaccine. “They’re still at much higher risk for getting the virus than [most] people who are fully vaccinated,” Liu said, adding that there’s a lot of virus out there, and many people are unvaccinated and remain at risk for COVID-19.

Adalja, on the other hand, said even in these sorts of scenarios there’s no real need for a test as long as you’re asymptomatic, given that the risk of contracting and spreading the infection after vaccination is so rare. “I would not recommend it.”

Ultimately, it’s your call. If getting tested will bring you peace of mind, go for it. It’s tough to make any sort of hard-and-fast rule about getting tested after vaccination in various situations since the coronavirus is still so widespread. Our knowledge and the guidance is changing so fast, and the more vaccinated our population becomes, the less necessary tests will be.

Experts are still learning about COVID-19. The information in this story is what was known or available as of publication, but guidance can change as scientists discover more about the virus. Please check the Centers for Disease Control and Prevention for the most updated recommendations.