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Experts say vaccines help prevent serious illnesses from COVID-19, but they don’t protect you from contracting the virus. Frederic J. Brown/AFP/Getty Images
  • Experts say people can still spread and even develop COVID-19 after getting a vaccine.
  • They note the immunity from the vaccine doesn’t begin to emerge until at least 12 days after inoculation.
  • They add the vaccine doesn’t prevent coronavirus infection. It helps protect against serious illnesses.
  • Experts advise people who get vaccinated to continue wearing a mask, washing their hands, and maintaining proper physical distancing.

All data and statistics are based on publicly available data at the time of publication. Some information may be out of date.

There’s growing evidence that even after you receive a COVID-19 vaccine, you still should mask up and maintain your physical distance.

That’s because you can still be infected by the novel coronavirus.

Rep. Bonnie Watson Coleman, a congressional representative from New Jersey, said she got her first dose of the Pfizer vaccine and was careful to continue isolating herself.

She is 75 years old and a cancer survivor.

However, in an op-ed in the Washington Post, Coleman writes she believes she contracted the virus while in lockdown for hours, in close quarters, following the riot at the U.S. Capitol on Jan. 6.

Coleman was careful to wear her mask but says she’s angry other lawmakers did not and put her at risk. A few days later, she and a handful of other representatives tested positive for COVID-19.

In San Diego, a 45-year-old emergency nurse known only as Matthew W. got his first dose of the Pfizer vaccine in mid-December.

Six days later, after working a shift in the COVID unit, he developed chills, muscle pain, and fatigue, and tested positive.

And in the United Kingdom, one of the first people to get the Pfizer vaccine, 85-year-old Colin Horseman, died a few days after testing positive for COVID-19.

He had been admitted to the hospital for a suspected kidney infection in late December and may have acquired the virus there.

He was scheduled to get his second dose of the vaccine 2 days before he died.

Stories like those may become more widespread as more people are vaccinated.

Experts say there are a number of ways you could test positive after receiving your vaccine.

For starters, you might have been infected before you even got your shot.

“That happened in the clinical trials,” said Dr. William Schaffner, an infectious disease specialist at the Vanderbilt University School of Medicine in Tennessee.

“Some people were unknowingly infected before they received their first dose,” he told Healthline. “Then, that infection manifested itself.”

There is also a lag time between when you get your first shot and when your body starts building immunity.

A study in the New England Journal of Medicine says protection from the first dose of the Pfizer vaccine doesn’t start for about 12 days, then it’s estimated to be about 52 percent effective a few weeks later.

Both the Pfizer and Moderna vaccines require two doses.

Both reported being about 95 percent effective, but that’s at least a week or two after the second dose.

And it still could leave some people unprotected.

“That’s not 100 percent,” said Dr. Paul A. Offit, an infectious disease expert and director of the Vaccine Education Center at Children’s Hospital of Philadelphia, in an interview with NPR. “That means one out of every 20 people who get the vaccine could still get moderate to severe infection.”

The vaccine works to keep you from getting severely ill.

But if you get infected, it may not prevent you from spreading the virus to others.

That’s something scientists are studying now.

“The vaccine is very effective in preventing symptomatic disease,” said Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security in Maryland.

“But is it effective at preventing asymptomatic disease? There’s an open question about how much the vaccine is going to decrease transmission. It will take time to do those studies,” he told Healthline.

In December, Moderna submitted data to the Food and Drug Administration showing that its vaccine prevented two-thirds of all infections, including asymptomatic ones.

That was a secondary finding from its testing. Now the company is conducting a further smaller study.

“That’s the data that has made us optimistic. That, particularly after getting two doses, we may not only be protected from illness but protected from infection itself,” said Schaffner.

Some experts suggest you should continue to act as if you never got the vaccine.

The Centers for Disease Control and Prevention advises people to keep following COVID-19 protocols because there is not enough information yet to recommend that you stop.

Experts add you may be following those recommendations for months to come.

“I think there will still be mask recommendations and guidance from the government until we cross the herd immunity threshold,” said Adalja.

That could take a while.

The rollout of the vaccine in the United States has been chaotic and is moving slowly.

The new administration is vowing to speed that up, promising to administer 100 million vaccines in the first 100 days.

“It’s entirely understandable that people are eager to drop all the protections,” Schaffner said. “But in the meantime, everybody who’s been vaccinated has got to keep wearing the mask.”