Senators from both sides of the aisle grilled top health officials, including Dr. Anthony Fauci, on the latest COVID-19 guidance during a Health, Education, Labor and Pensions committee hearing Tuesday.
Democrats and Republicans both demanded better communication on rules for testing, isolation and quarantine.
"I'm not questioning the science ... but I'm questioning your communication strategies. It's no wonder that the American people are confused," Sen. Richard Burr of North Carolina, who is also the ranking committee Republican, said.
Committee chair Sen. Patty Murray, D-Wash., said: "I have heard from so many people who find the latest CDC isolation and quarantine guidance confusing and hard to interpret."
Murray pressed Centers for Disease Control and Prevention Director Dr. Rochelle Walensky to provide not just "background" but a "straightforward" answer.
"If they are exposed to COVID-19 and they are completely boosted, they should -- they do not need to stay home, but they should get a test at day five," Walensky responded.
"If they have COVID, our guidance does not distinguish between your vaccination status. And our science has demonstrated that you're maximally infectious two days before and two to three days after," Walensky continued.
"By five days after your symptoms, if you're feeling better, if your fever is better, if your cough and sore throat are better, then on day six you can go out," Walensky said. "But you have to wear a mask -- you have to wear a mask reliably and you should not go to places you can't wear a mask. You probably shouldn't go and visit grandma, you shouldn't get on an airplane."
Sen. Mitt Romney, R-Utah asked for clarity on the latest definition of exposure.
"When you say what people have been exposed, please let us know what it means to be exposed. We're in a room right now -- I'm sure someone here has omicron. Are we all exposed? And therefore, need to get tested? What does it mean to be exposed? And when do we need to get tested?" Romney asked.
Fauci reiterated that the CDC guideline for exposure is if you are in close contact with someone with COVID-19 for "a period of 15 minutes at a time, or a total of 15 minutes over a 24-hour period."
CDC guidance is to test on day five if you are exposed.
Sen. Tammy Baldwin, D-Wis., brought up the scarce availability of N95 masks.
"Americans still can't go to a local pharmacy and purchase an American-made N95," Baldwin said. "So President [Joe] Biden has now personally urged Americans to upgrade the quality of the masks they wear -- I want to know when the American people will be able to buy an American-made N95 mask?"
Dawn O’Connell, assistant secretary for preparedness and response at the Department of Health and Human Services, told the committee that the Biden administration plans to sign a contract with a supplier by next month to get 140 million N95 masks per month.
Some 737 million N95 masks are in the national stockpile that could be provided to hospitals that need them, and those masks come from a dozen domestic suppliers, she said.
O’Connell said the plan is to reach an agreement with a company to create "warm-based manufacturing," meaning the factory would be able to expand in times of high demand.
"We are very invested in N95 masks being made available. And we'll continue to look -- and I appreciate your support in getting us the American rescue plan dollars that we're currently investing -- and we'll continue to look at the right ways to invest," she said.
This hearing also featured another contentious exchange between Fauci and Republican Sen. Rand Paul.
Paul asked Fauci about his email correspondence and accused Fauci of trying to "attack scientists who disagree with you."
Fauci responded, "You keep distorting the truth."
"I brought together a group of people to look at every possibility with an open mind ... you're completely turning it around," Fauci said.
Fauci said the purpose of the committee is to help the American public, but he said Paul instead chooses to "keep coming back to personal attacks on me that have absolutely no relevance."
He added that Paul's attacks are "for political reasons" and inspire "the crazies out there."
Fauci referenced the December arrest of a California man who, at a traffic stop, was allegedly found with an AR-15-style rifle, loaded magazines, boxes of ammunition and body armor. Prosecutors said the driver downloaded TikTok videos, compiling a list of people he allegedly wanted to kill, including Fauci and former Presidents Bill Clinton and Barack Obama.
Fauci and Paul have butted heads repeatedly. At a hearing in July 2021, Paul and Fauci got in a shouting match over COVID-19's origins.
ABC News' Anne Flaherty contributed to this report.