Feb. 11 (UPI) -- People who have received both doses of the Pfizer-BioNTech or Moderna COVID-19 vaccines do not need to quarantine if they have been exposed to a person infected with the virus, according to the U.S. Centers for Disease Control and Prevention.
The changes to the coronavirus quarantine guidelines were made late in the day on Wednesday and reflected on the agency's web site.
"Fully vaccinated persons who meet criteria will no longer be required to quarantine following an exposure to someone with COVID-19," according to the updated guidance.
"Fully vaccinated" means that at least two weeks have passed since a person has received the second dose of a two-dose vaccine.
Both of the vaccines currently approved for use in the United States -- from Pfizer-BioNTech and Moderna -- require two doses to provide full protection, the CDC said.
As these vaccines were developed with similar processes, some people have received a first dose with one and a second dose with the other. Still, if a person has received two doses of either vaccine they are considered "fully vaccinated," the agency said.
Since the start of the pandemic last March, the CDC has recommended that people who may have been exposed to a person with COVID-19 quarantine or self isolate for a period of time to avoid potentially spreading the virus to others.
Although the quarantine period has changed at several times over the past year, the agency has generally advised people to remain isolated from others for one to two weeks to allow time for COVID-19 symptoms to develop or to have a diagnosis confirmed via multiple tests.
People who have had the virus and recovered do not need to quarantine for 90 days after the illness, even if they are exposed to someone who is infected, according to the CDC.
In the updated guidelines, fully vaccinated people do not need to quarantine after possible exposure to an infected person within three months after their second dose provided they do not develop any symptoms.
However, the agency said they should continue wearing masks, social distancing and avoiding crowds and poorly ventilated indoor spaces, as it is possible they can still spread the virus to others.
"Vaccination has been demonstrated to prevent symptomatic COVID-19 [and] symptomatic and pre-symptomatic transmission is thought to have a greater role in transmission than purely asymptomatic transmission," the guidelines state.