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CDC waives quarantine for vaccinated people after COVID-19 exposure, experts still say wear a mask

People who have been fully vaccinated against the coronavirus won’t be required to quarantine if they’ve been exposed to someone with COVID-19, according to the latest guidance by the U.S. Centers for Disease Control and Prevention. 

The CDC’s guidelines were updated on Wednesday.

"Fully vaccinated persons who meet criteria will no longer be required to quarantine following an exposure to someone with COVID-19," the CDC wrote. 

The health agency says that vaccinated individuals who have been exposed to someone with suspected or confirmed COVID-19 are not required to quarantine if they meet all of the following criteria: 

  • Are fully vaccinated (i.e., ≥2 weeks following receipt of the second dose in a 2-dose series, or ≥2 weeks following receipt of one dose of a single-dose vaccine)
  • Are within 3 months following receipt of the last dose in the series
  • Have remained asymptomatic since the current COVID-19 exposure

"Persons who do not meet all 3 of the above criteria should continue to follow current quarantine guidance after exposure to someone with suspected or confirmed COVID-19," the CDC said.

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The CDC added an exception to its guidance, saying, "vaccinated inpatients and residents in healthcare settings should continue to quarantine following an exposure to someone with suspected or confirmed COVID-19." 

"This exception is due to the unknown vaccine effectiveness in this population, the higher risk of severe disease and death, and challenges with social distancing in healthcare settings," the CDC said. 

The makers of all three vaccines — Moderna, Pfizer and AstraZeneca — have said that their shots proved to be anywhere from 70% to 95% effective in clinical trials in protecting people from illness caused by the virus. But it was unclear whether the vaccines could also suppress transmission of the virus — that is, whether someone inoculated could still acquire the virus without getting sick and spread it to others.

As a result, experts have been saying that even people who have been vaccinated should continue to wear masks and keep their distance from others.

Guidance by Johns Hopkins University, one of the leading counters of coronavirus deaths and cases echoes this concern.

"Also, while the vaccine may prevent you from getting sick, it is unknown at this time if you can still carry and transmit the virus to others," Johns Hopkins writes on their website. "That is why, until more is understood about how well the vaccine works, continuing with precautions such as mask-wearing and physical distancing will be important."

The CDC also says "mRNA vaccines are not currently recommended for outbreak management."

"A lot of people are thinking that once they get vaccinated, they’re not going to have to wear masks anymore," Michal Tal, an immunologist at Stanford University told the New York Times. "It’s really going to be critical for them to know if they have to keep wearing masks, because they could still be contagious."

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The CDC’s updated guidance says it is "still uncertain," whether someone who has been vaccinated could still spread the virus. But the agency says "vaccination has been demonstrated to prevent symptomatic COVID-19; symptomatic and pre-symptomatic transmission is thought to have a greater role in transmission than purely asymptomatic transmission."

"Additionally, individual and societal benefits of avoiding unnecessary quarantine may outweigh the potential but unknown risk of transmission, and facilitate the direction of public health resources to persons at highest risk for transmitting SARS-CoV-2 to others," the CDC added. 

The health agency said their most updated recommendation to waive quarantine for people with "vaccine-derived immunity aligns with quarantine recommendations for those with natural immunity, which eases implementation."

The CDC did not immediately respond for comment on the updated guidance. 

The Associated Press contributed to this story.