In every outbreak, some people are more susceptible than others. The current coronavirus pandemic preys on the elderly, for instance, and on people with underlying ailments. But in the United States, poll after poll shows the virus has found a population that’s particularly likely, through nonchalance and neglect, to help it spread. That population is Republicans.

Republicans don’t deserve collective blame. But in an epidemic, it’s important to confront the most efficient routes of transmission. In this case, the attitudes and behaviors likely to spread the virus are more prevalent in the GOP, and they need to be addressed by politicians and media organizations with conservative audiences.

Public opinion is shifting as the crisis mounts, so questions asked a week ago would get different answers today. But one pattern has persisted: In every poll, Republicans have expressed far less concern about the virus than Democrats have. Last week, 55 percent of Republicans, compared with 25 percent of Democrats, said they didn’t worry much about it. Forty-eight percent of Republicans, versus 18 percent of Democrats, expressed little or no concern “about a coronavirus epidemic here in the United States.” Sixty-three percent of Republicans, as opposed to 31 percent of Democrats, said they were similarly unconcerned “that you or someone you know will be infected.”

In a Marist/NPR poll taken on Friday and Saturday, 42 percent of Republicans, compared with 16 percent of Democrats, said they weren’t very concerned about the virus spreading “to your community.” When respondents were asked whether “the coronavirus is a real threat or blown out of proportion,” three-quarters of Democrats said it was a real threat. Most Republicans said it was blown out of proportion. A Gallup poll completed on Friday found that from the first half of February to the first half of March, the percentage of Democrats who worried about the virus increased by 47 points. The percentage of Republicans who worried about it increased by 12 points.

Republicans, much more than Democrats, have been willing to entertain the idea that the virus is a hoax. Last week, in an Economist/YouGov survey, 16 percent of Republicans, compared with 10 percent of Democrats, said it was definitely or probably a hoax. Those numbers and the gap between them are fairly small. But when you factor in all the additional people who said it could be a hoax, the gap gets a lot bigger. Seventy-three percent of Democrats said the virus definitely wasn’t a hoax. Only 54 percent of Republicans agreed.

Republicans, much more than Democrats, have been willing to entertain the idea that the virus is a hoax.

Given their relative skepticism and disinterest, Republicans have been far less likely than Democrats to take steps to prevent transmission of the virus. In a Civiqs/Daily Kos poll taken last week, only 23 percent of Republicans, compared with 46 percent of Democrats, said they were “taking precautions” or had “changed some of my day-to-day habits” to deal with the virus. In a Yahoo News/YouGov survey, only 55 percent of Republicans, versus 67 percent of Democrats, said they were washing their hands more often. Only 29 percent of Republicans, compared with 44 percent of Democrats, said they were avoiding “crowded public places.”

An NBC News/Wall Street Journal poll, taken from Wednesday to Friday, found that 61 percent of Democrats had stopped or were planning to stop “attending large public gatherings like movies, concerts or sporting events.” Only 30 percent of Republicans said the same. A Kaiser Family Foundation poll, taken from Wednesday to Sunday, found a similar partisan split. So did the NPR/Marist survey. In the Marist poll, 60 percent of Democrats, but only 36 percent of Republicans, said they had “decided to eat at home more often.” In the NBC survey, only 12 percent of Republicans, compared with 36 percent of Democrats, said they had stopped or were planning to stop eating at restaurants.

Republicans have also expressed less willingness to be vaccinated. In three surveys taken this month, Morning Consult asked, “If a vaccine that protects from the coronavirus became available, would you get vaccinated, or not?” On average, when compared with Democrats, Republicans were 10 percentage points less likely to accept the vaccine and five points more likely to refuse it.

Why have Republicans been so unmoved? One possibility is that they’re more likely to live in rural areas, where people are spread out. But survey after survey shows no correlation between population density and concerns about the virus. Another guess is that Republicans are less likely to live in places where outbreaks have been reported. Polls support that theory. But they also show that it can’t account for the partisan gap.

In the Civiqs poll, 9 percent of Republicans and 23 percent of Democrats said the coronavirus had been reported in “your local area.” That’s a 14-point difference, and it helps to explain why Republicans, in the same survey, were more skeptical of a local outbreak. But thanks to the way the poll was constructed, you can filter the 9 percent and the 23 percent out of the sample. This allows you to look just at respondents who said the coronavirus had not been reported in their communities. Among this population—with no partisan difference in reported local infections—was there still a partisan gap in attitudes? The answer, decisively, is yes. In locally unaffected communities, 57 percent of Republicans, compared with 23 percent of Democrats, said an outbreak in their area was only “a little likely” or “not likely at all.”

If local experience doesn’t explain the partisan difference in attitudes, it’s reasonable to ask whether a partisan difference in media consumption—namely, watching Fox News—does. The Civiqs poll found that people who frequently watched the network, when compared with people who didn’t watch it at all, were more likely, by about 20 percentage points, to say that a local coronavirus outbreak was implausible. They were also more likely, by about 30 points, to express little or no concern about such an outbreak. But in each case, the partisan gap was more than 10 points bigger than the Fox gap. The party you belong to is a better predictor than the network you watch.

Only one factor has outscored partisanship as a predictor of coronavirus attitudes: support for President Donald Trump. In some surveys, when compared with Republicans as a whole, people who strongly approve of Trump’s job performance have been slightly more likely to say that they’re unconcerned about the emergence of the virus (by 7 percentage points), about its spread in the United States (by 5 points), and about contracting it themselves (by 4 points). They’ve been more likely to dismiss it as a minor or nonexistent health risk (by 8 points) and to say they wouldn’t get vaccinated (by 3 points). Maybe these people have discounted the virus because Trump has discounted it. Or maybe they just share his imperviousness to unwelcome facts.

Either way, Republicans—and Trump supporters in particular—are a major concern in the next phase of this public health crisis. The fact that more Democrats than Republicans have reported local outbreaks suggests that the virus began its American rampage in left-leaning pockets of the country. Perhaps that’s because these hot spots, such as Seattle, were more open to global travel. But from there, the virus is likely to be spread by people who don’t take it seriously. They’re the people who keep eating at restaurants, keep going to malls and movies, and don’t wash their hands. All too often, they’re Republicans. They need better guidance from the leaders and news organizations they trust.

For more on the coronavirus, listen to Wednesday’s What Next.