WASHINGTON – Three members of Congress contracted the novel coronavirus after sheltering in a crowded room as a pro-Trump mob stormed the Capitol, testing positive shortly after getting a first dose of the coronavirus vaccine.

Those positive tests do not mean the vaccines were faulty, experts said, noting that immune protection takes more than a week to kick in. The Pfizer-BioNTech and Moderna vaccines that are available to Americans require two doses for full protection; a single dose is not as effective as two.

“Early protection against covid-19 may occur from about 12 days after dose one,” said Naor Bar-Zeev, an infectious diseases physician and epidemiologist at Johns Hopkins Bloomberg School of Public Health. People “should not really consider themselves protected really until after a week or two following Dose 2.”

Even though the vaccines may protect people from showing symptoms, those vaccinated could remain susceptible to infection, he said, which is why officials are urging those who have been recently vaccinated to continue to follow public health advice such as washing hands and wearing masks.

“We absolutely have to continue to wear masks and keep our distance, particularly after that first dose – and even after the second dose,” said immunologist Nicole Lieberman, a research scientist at the University of Washington.

The Pfizer and the Moderna vaccines are about 95% effective after two doses, according to the companies. Pfizer’s vaccine consists of two doses, given two weeks apart, and Moderna’s contains two doses given 28 days apart.


Reps. Bonnie Watson Coleman, D-N.J., Bradley Schneider, D-Ill., and Pramila Jayapal, D-Wash., tested positive this week. All three of the lawmakers have said they received the first dose of coronavirus vaccine in the days before the riot.

Coleman is a 75-year-old cancer survivor who said last week’s trip to the District of Columbia was her first in months. She said in an opinion article for The Washington Post that she was apprehensive about it because other people at the Capitol might “flout social distancing and mask guidelines.”

Coleman received her first vaccine dose Dec. 29.

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Schneider drives from his home near Chicago to Washington to avoid flying because his wife has a health condition that makes her more susceptible to the virus.

He received his first shot on Jan. 4, two days before the attack. He did not report feeling symptoms after his positive test results.

Jayapal also received her first shot on Jan. 4. On the day between the shot and the lockdown, she had a negative test result, a spokesman said.


“Even though the members in question have been vaccinated, their bodies hadn’t had time to react yet,” Lieberman said.

At least 10.3 million coronavirus vaccines have been administered nationwide as of Wednesday, according to Washington Post data. The shots come amid a worsening pandemic, with more than 4,000 dying of covid-19, the disease caused by the virus, on Wednesday. More than 225,000 new cases were reported.

The lawmakers were among those who huddled in a crowded room after the Capitol was locked down last week. Though large, the windowless room was too full for people to stay distant its occupants – including some who were not wearing masks – spent hours together.

The Office of Attending Physician at the Capitol said Sunday that lawmakers may have been exposed to someone infected with the coronavirus while in “protective isolation.”

Genetic testing of the coronavirus pathogen, if the sequences matched, would help confirm whether the three lawmakers’ cases are related. “Without doing the sequencing to confirm who was the patient zero, we can’t know for sure,” Lieberman said.

But she and other experts said the simplest explanation, considering the circumstances, was that the virus spread in the lockdown room.


“It’s highly likely – and I think probable – that this is a superspreader event, and these lawmakers caught it from spending time in that room,” said Harvard University environmental health expert Joseph Allen.

Krystal Pollitt, an environmental health sciences professor at Yale University, said that as she watched the live feed of lawmakers, even before they were moved to the secure location, “all that could go” through her mind was how dangerous the situation was for transmitting the virus.

Video shows Republican lawmakers refusing the masks Rep. Lisa Blunt Rochester, D-Del., offered them.

“People are projecting their voices, not wearing masks – there’s a lot of people in the space,” Pollitt said. “You see the people sitting opposite of one another; they are right in the plume of others that are speaking.”

Rep. Marjorie Taylor Greene, R-Ga., told Fox News that she and her colleagues declined the masks because they did not have symptoms.

Greene told The Washington Post in an email: “It is absolutely ridiculous and insane to blame those of us who did not have covid or symptoms.”


But because asymptomatic people spread the virus, health officials have urged everyone to wear masks in public spaces regardless of whether they feel healthy.

Pollitt said that based on rough estimates, “you could have a fairly high number of people that are infected” within 90 minutes, she said.

Even a well-functioning HVAC system would be pushed to its limits, Pollitt said, to sufficiently exchange air and prevent transmission among unmasked people in an enclosed, windowless room.

“If someone is infectious in that room, others will be infected,” Allen said. “This is just another consequence of a truly shocking and unbelievable day in American history.”

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The Washington Post’s Colby Itkowitz contributed to this report.