Rep. Stephen Lynch (D-Mass.), who received a second dose of the COVID-19 vaccine earlier this month, tested positive for the virus on Friday.
Another Democrat from Massachusetts, Rep. Lori Trahan, announced Thursday she had also tested positive. Both lawmakers are reportedly asymptomatic.
Lynch received two doses of the Pfizer-BioNTech vaccine prior to the inauguration of President Joe Biden on Jan. 20, Molly Rose Tarpey, Lynch’s communications director, said in a statement.
“While Mr. Lynch remains asymptomatic and feels fine, he will self-quarantine and will vote by proxy in Congress during the coming week,” she said.
Tarpey did not specify the exact date Lynch received the second dose of the vaccine.
Trahan said in a statement that she would also vote by proxy while she self-quarantined. She received her first shot of one of the vaccines last week, her spokesperson Francis Grubar told The Washington Post.
According to the Centers for Disease Control and Prevention, it is possible for people to test positive after receiving one or both doses of the vaccine.
“It typically takes a few weeks for the body to build immunity (protection against the virus that causes COVID-19) after vaccination,” the CDC website stated. “That means it’s possible a person could be infected with the virus that causes COVID-19 just before or just after vaccination and still get sick. This is because the vaccine has not had enough time to provide protection.”
Public health experts have stressed that it can take a week or two after the second shot for the vaccine to reach its maximum efficacy. According to the CDC, people who have received both vaccine doses are still advised to wear masks and practice social distancing and good hygiene.
Experts don’t yet know if people who have received the vaccine can still spread the virus, even if they don’t get sick themselves.
“While experts learn more about the protection that COVID-19 vaccines provide under real-life conditions, it will be important for everyone to continue using all the tools available to help stop this pandemic,” the CDC website stated.
Several other House Democrats tested positive for COVID-19 after they went into lockdown with Republican members of Congress, some of whom refused to wear masks, during the Jan. 6 Capitol insurrection.
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This article originally appeared on HuffPost and has been updated.