Although there had been only two cases of Ebola transmission inside the United States and both patients had survived, a November 2014 opinion poll revealed that the U.S. public ranked Ebola as the third-most-urgent health problem facing the country — just below cost and access and higher than any other disease, including cancer or heart disease, which together account for nearly half of all U.S. deaths each year (see Table S1 in the Supplementary Appendix, available with the full text of this article at NEJM.org).

The U.S. public's high ranking of a disease is important because it can influence policy leaders' views of appropriate actions and spending, running the risk of redirecting attention and funds from health policies that help more people domestically or from critical responses overseas. This kind of jump in public priorities related to emerging infectious diseases has happened before, including during the H1N1 influenza pandemic in 2009 (see the Supplementary Appendix).

To examine the reasons for such a public response, we used Ebola as a case study. In a project supported by the Robert Wood Johnson Foundation, we reviewed 179 public opinion polls about Ebola (2 of which were conducted by researchers at the Harvard T.H. Chan School of Public Health and SSRS) and conclude that there were primarily four interrelated reasons why the public prioritized Ebola. Our findings have implications for effective communications with the public during future outbreaks of emerging infectious diseases (for a list of referenced polls and reports, see the Supplementary Appendix).

The U.S. Public's Attitudes, Beliefs, and Knowledge about Ebola.

A central reason for the high priority placed on Ebola is that people did not understand, or perhaps did not believe, information about how this gruesome disease spreads. The vast majority of those polled (85%) said a person is likely (“very likely” or “somewhat likely”) to get Ebola if he or she is sneezed or coughed on by a symptomatic person, and half (48%) said a person could transmit the virus before he or she shows symptoms (see table). These descriptions conflict with evidence that the virus is not airborne — meaning that people are extremely unlikely to get sick from someone sneezing or coughing — and that Ebola is not contagious before symptoms appear.

As a result of such misperceptions, people felt personally threatened. At the peak of concern, about half the U.S. public (45%) was worried (“very worried” or “somewhat worried”) that they or their family would become sick with Ebola. These responses were obtained in mid-October 2014, when Ebola was transmitted in a U.S. hospital despite precautions, which reinforced the idea that it spreads easily. Worry then diminished after no other people became infected, even though people with Ebola had been in public places while they had symptoms (see Table S2 in the Supplementary Appendix).

The media most likely played a role in increasing public concern, primarily by running many stories about Ebola.1 Nightly news shows on three major networks — CNN, NBC, and CBS — aired nearly 1000 segments about Ebola between mid-October and early November 2014,2 when the majority of the U.S. public (76 to 81%) said they were following news on Ebola “very closely” or “fairly closely.” The media's style of coverage may also have shaped public perception, in that it followed specific people, such as one of the nurses who was infected. Naming individual patients was logical because there were so few of them in the United States, but political science research suggests that this practice can drive public concern.3

The level of public concern was also high because communications that might otherwise have reduced it, such as information about the limited mechanisms by which Ebola is spread, were not well trusted. Only 31% of the public said they trusted public health officials in the United States (“a great deal” or “a fair amount”) to share complete and accurate information about the Ebola virus, and 40% of the public said they did not trust information (“not too much” or “not at all”) about the Ebola outbreak from the Centers for Disease Control and Prevention (CDC) (see table).

Though this low level of trust may have derived in part from the media's criticisms of the Ebola response mounted by major public health organizations,4 it also probably reflects longer-standing levels of distrust in scientists and government. In a 2013 poll by YouGov and the Huffington Post, only 36% of the public said that they generally trusted (“a lot”) that what scientists say is accurate and reliable, whereas 57% said they trusted what scientists say only “a little” or “not at all.” Furthermore, in a November 2014 poll by Quinnipiac University, only 14% of the public said they trusted the federal government to do what is right “almost all the time” or “most of the time,” which is one of the lowest proportions since researchers began tracking this measure in 1958.

The cases of Ebola inside the United States coincided with the lead-up to the November 3 national elections. This coincidence may have increased public concern, because media coverage increased as candidates commented about Ebola. Moreover, research suggests that during election season, segments of the public — particularly partisans of the party that's out of power — may be skeptical of information provided by the government, including information that would otherwise reassure them.5 Polling data provide some evidence that a partisan split occurred during the Ebola outbreak. For example, analysis of a poll by the Pew Research Center shows that about half (49%) of Republicans expressed low trust in information from the CDC (“not much” or “not at all”), as compared with 30% of Democrats.

Whether or not Ebola appears again in the United States, we are likely to see other emerging infectious diseases quickly become top domestic health concerns. If that happens, we run the risk of substantially altering policy actions and spending in ways that do not serve the greatest domestic or global health needs. Our experience with Ebola suggests that in addition to the self-evident truth that public health organizations need to work effectively to address any real threat, there are specific considerations for effective communications in this context.

Perhaps most important is that public health leaders can expect the public to be very concerned about a new disease at first. Furthermore, during this initial reaction, such leaders will have to be prepared for intense media scrutiny and be aware that they will be working in the context of preexisting low levels of public trust.

More concretely, it may be useful to have preestablished relationships with independent health professional associations that are trusted by the public in order to come to broad agreement on policies and approaches before they are shared with the public. It may also be useful to acknowledge uncertainty where it exists and to justify policies by explaining relevant underlying scientific information — such as modes of transmission — rather than by simply citing scientists' consensus. Scientific information can be explained to the public directly and repeatedly in simple language. Clear communication with journalists using the same language may be useful in minimizing unnecessary media sensationalism.

During an election period, public health leaders can expect politicians from the nonincumbent party to be critical of their actions. It may therefore be useful to reach out to political leaders and gain the support of nonpartisan groups that can help reduce any polarization of the issue.

We believe that keeping these lessons in mind could help limit disconnects between public health leaders and the public they serve, leading more often to appropriate and needed policies.