Just 45% of House Republicans say they've been vaccinated while 100% of congressional Democrats say they've gotten the shot

• Every Democratic lawmaker in the House and Senate says they've received a COVID-19 vaccine.
• But just 45% of House Republicans say they've been vaccinated, while four GOP senators haven't gotten the shot.
• Skepticism and opposition to the COVID-19 vaccines is widespread among conservatives and is hindering the US's efforts to achieve herd immunity.

Every single Democratic lawmaker in the House and Senate says they've received a COVID-19 vaccine, according to a new CNN survey. Things are quite different on the other side of the aisle.

Just 45% of House Republicans say they've been vaccinated. A much higher percentage of Republicans in the upper chamber say they've received vaccinations, but four GOP senators either said they won't get the shot or wouldn't reveal the information.

Overall, about 72% of House lawmakers say they've been vaccinated - 312 of the 431 members. Ninety-five GOP House members told CNN they've gotten the shot, 112 didn't respond to multiple inquiries, and five members confirmed they haven't been vaccinated or didn't want to reveal whether they had.

"I'm not going to talk about it. I don't think anybody should have to share their personal, private medical information with anybody," said Rep. Greg Steube of Florida.

Republican Sens. Rand Paul of Kentucky and Ron Johnson of Wisconsin have been particularly outspoken about their skepticism of the scientific consensus and have refused to get vaccinated. Both lawmakers say they're protected by antibodies after their COVID-19 infections, but health experts don't know how long immunity from an infection lasts and the CDC recommends that people who've been infected still get vaccinated.

Opposition to the COVID-19 vaccines is particularly widespread among conservatives. 43% of Republicans said they would probably never get the vaccine, according to an April Monmouth poll. Vaccination rates are particularly low in counties that voted for Trump in 2020.

Public health experts say that a combination of vaccine hesitancy, lack of access to the shot, and the growth of new variants will make achieving herd immunity in the US unlikely or even impossible.

Prominent Republicans have sided with many of their vaccine hesitant constituents in arguing that Americans shouldn't feel shamed or pressured into getting the vaccine.

Sen. Mike Braun said it's "a step too far" for lawmakers to publicize their own vaccination in order to encourage their constituents to get the shot.

"You should feel free to do it if you want to do it," Sen. Kevin Cramer told CNN earlier this year. "You should not feel ashamed to not do it if you don't want to do it. This is a free country."

House Speaker Nancy Pelosi said she won't end the mask mandate on the House floor until every lawmaker has been vaccinated, despite the CDC's recent determination that fully vaccinated Americans can stop wearing masks in most indoor settings. The decision has prompted pushback from some Republicans.