A California congressman contracted the coronavirus before he could get a second dose of vaccine that would have improved his immunity.

Democratic Rep. Lou Correa announced Saturday he tested positive upon returning home from Washington, D.C., prompting him to self-quarantine away from his family.

His office said he received the first dose of the Pfizer-BioNTech vaccine on Dec. 19 and has not received the second shot that would have boosted his immunity to about 95%.

“While this diagnosis will prevent me from attending the much-anticipated inauguration of President-elect Joe Biden, I look forward to working with the new administration to unite our country and help the millions of people devastated by the pandemic,” Correa said in a statement.

Correa, who represents central Orange County, is the latest House member to report testing positive since dozens of lawmakers huddled together for protection during the Jan. 6 insurrection at the U.S. Capitol. Democratic Rep. Adriano Espaillat of New York said Thursday he contracted the coronavirus even after getting the second dose of the vaccine.

Correa’s office said he was not in the secure room but was outside assisting Capitol Police. He was confronted later last week by a group of Donald Trump supporters, some not wearing masks, at Dulles International Airport in Virginia.

The vaccine is about 52% effective after the first dose, Pfizer-BioNTech said. The efficacy of the vaccine rises to about 95% after the second dose.