Public Response to an Anthrax Attack: Reactions to Mass Prophylaxis in a Scenario Involving Inhalation Anthrax from an Unidentified Source

Abstract

An attack with Bacillus anthracis (“anthrax”) is a known threat to the United States. When weaponized, it can cause inhalation anthrax, the deadliest form of the disease. Due to the rapid course of inhalation anthrax, delays in initiation of antibiotics may decrease survival chances. Because a rapid response would require cooperation from the public, there is a need to understand the public's response to possible mass dispensing programs. To examine the public's response to a mass prophylaxis program, this study used a nationally representative poll of 1,092 adults, supplemented by a targeted focus on 3 metropolitan areas where anthrax attacks occurred in 2001: New York City (n=517), Washington, DC (n=509), and Trenton/Mercer County, NJ (n=507). The poll was built around a “worst-case scenario” in which cases of inhalation anthrax are discovered without an identified source and the entire population of a city or town is asked to receive antibiotic prophylaxis within a 48-hour period. Findings from this poll provide important signs of public willingness to comply with public health recommendations for obtaining antibiotics from a dispensing site, although they also indicate that public health officials may face several challenges to compliance, including misinformation about the contagiousness of inhalation anthrax; fears about personal safety in crowds; distrust of government agencies to provide sufficient, safe, and effective medicine; and hesitation about ingesting antibiotic pills after receiving them. In general, people living in areas where anthrax attacks occurred in 2001 had responses similar to those of the nation as a whole.

This nationwide poll explored whether, in the event of an anthrax incident, respondents would be willing to go to a dispensing site, receive antibiotics, and take the antibiotics as directed. It also asked whether they would be willing to give the antibiotics to their children.

The 2001 anthrax attacks demonstrated the feasibility of carrying out a bioterrorist attack on United States soil. The health impacts of the attack included the deaths of 5 people, significant illness for 17 more, and mental strain for thousands,^1–3 while the financial cost of response and recovery has been estimated at more than $6 billion.⁴ Seven years after the attacks, the Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism made clear that further attacks are possible in the relatively near term, stating specifically that “unless the world community acts decisively and with great urgency, it is more likely than not that a weapon of mass destruction (WMD) will be used in a terrorist attack somewhere in the world by the end of 2013. That weapon is more likely to be biological than nuclear.”⁵^(p1) Although the U.S. federal government has allocated an estimated $50 billion since 2001 toward efforts to quell the threat of biological weapons and enhance response capacity,⁶ there are nonetheless important gaps in its preparedness. In particular, the Commission's 2010 Report Card gave an “F” grade to recent efforts to enhance the nation's “capabilities for rapid response to prevent biological attacks from inflicting mass casualties.”⁵

One critical strategy to reduce mass casualties when people may have been exposed to anthrax or other bacteria is the use of antibiotic prophylaxis, but the operational challenges of a mass prophylaxis program are immense. Aside from the logistics of storing and delivering antibiotics to relevant geographic areas and setting up dispensing systems, there would be an urgent need for widespread public compliance with recommendations to obtain and take prophylactic antibiotics, which may be challenging.^7–10 In order to improve the design and launch of such efforts, there is a need to understand how the public might respond to a mass prophylaxis program in the context of a biological attack, including factors that might dissuade them from complying with related public health recommendations and public expectations about information sources they would rely on for communications.

Little research has focused on public compliance with a mass prophylaxis program, and available studies are largely qualitative rather than quantitative. Findings from one such study indicate public eagerness for information about state and local government plans for bioterrorism response and predict, more specifically, reliance on local news during an attack.¹¹ Studies also suggest public concerns about the operation of a mass dispensing program, including whether there would be enough pills, sufficient instruction, and sufficient security at mass dispensing sites.^9,11 This research focuses less explicitly on the reasons for people's decisions about whether or not they would comply with recommendations to get antibiotics and thus has a more limited examination of reasons for noncompliance.

Studies of postal workers and government staff affected by the 2001 attacks provide some insights into factors that might contribute to prophylaxis noncompliance among a broader public, even though these populations had more (though imperfect) institutional support when making their decisions. Studies of these groups suggest there was relatively low compliance for taking antibiotics initially (approximately 70%)¹² and in following a longer-term, 60-day regimen (40% to 52%).^13–15 They generally conclude that reasons for nonadherence related largely to concerns about side effects and people's beliefs that they were not truly at risk of developing inhalation anthrax. For both groups, although perhaps particularly for postal workers, these reasons were interwoven with concerns about the accuracy and “trustworthiness” of information provided by federal and local public health officials.^13,15

Studies about public compliance to a broader set of public health officials' recommendations in other kinds of emergencies suggest similar concerns may play a role in the public's decision making. These studies show a role for concern about the risk of contracting the illness and about side effects of proposed treatments or preventive measures.^16–18 They also suggest that trust in public officials plays a role in public response. Studies point to multiple dimensions of trust that are relevant, including belief in the accuracy or “honesty” of information, a belief in the likelihood of public officials acting in the best interest of the public (“fiduciary responsibility”), and a belief in their competence.^17,19–21 Studies also suggest additional factors that may affect compliance, including level of concern about the seriousness of an illness,^16,17 misinformation or missing information about the nature of an illness or treatment,^22,23 and perceptions of the logistics of response programs.^10,18,24,25 These studies also provide some guidance as to the general sources of information most useful in public health emergencies, which include local television news, for example, although none is specific to the logistics or decision making regarding mass prophylaxis programs.^15,26,27

In this study, we used a nationally representative poll, supplemented by a targeted focus on 3 metropolitan areas where anthrax attacks occurred in 2001, in order to examine the public's response to a mass prophylaxis program. The focus of the poll was a “worst-case scenario” in which cases of inhalation anthrax are discovered without an identified source in a given city or town. This scenario forms the core of the Cities Readiness Initiative (CRI), which is a national effort funded by the Centers for Disease Control and Prevention (CDC) to support state and local public health department preparedness against large-scale bioterrorist events.²⁸ CRI currently covers 72 metropolitan statistical areas (MSAs), including at least 1 in every state.²⁸

The first goal of the mass prophylaxis effort is to provide a 10-day supply of antibiotics to everyone in a targeted area within 48-hours.* Antibiotics are delivered from the CDC's Strategic National Stockpile²⁹ to state and local public health departments, which then distribute them to the public using various approaches, including dispensing sites (also known as “points of dispensing” or “PODs”) that are established with local health partners in places like public health clinics or schools. This short time frame for dispensing is needed because of the possibility of a short incubation period for anthrax, which means people need to receive antibiotics as soon as possible, preferably before they experience symptoms.^30,31

This study was designed primarily to address the public's response to the mass prophylaxis program with the aim of providing broad insights about the public's response to the program's key dimensions, which could help shape planning and communications at the time of a real attack. We evaluated (1) people's willingness to go the dispensing site and get antibiotics; (2) reasons they identify specifically as barriers to going to the site; and (3) factors that might interfere with compliance more generally, including lack of concern about inhalation anthrax, misperceptions about contagiousness of the illness, disbelief in the safety and efficacy of the antibiotic pills, and a lack of confidence in the federal and state/local government's ability to carry out this program. We also examined the information sources the public would rely on and trust under such circumstances. Finally, we examined whether there were differences between the opinions of people nationally and those living in areas where anthrax attacks had occurred in 2001 in order to help determine whether any special efforts would need to be made to support people living in previously targeted localities in the event of a future attack.

Methods

In December 2009, the Harvard School of Public Health (HSPH) conducted a nationwide telephone poll (landline and cell) with a representative sample of 1,092 adults (18 years and older) using a random-digit dial (RDD) design. Additionally, the poll was conducted with representative RDD samples of adults in each of 3 metro areas where major terrorist/anthrax attacks had occurred in 2001: New York City (n=517), Washington, DC (n=509), and Trenton/Mercer County, NJ (n=507). Social Science Research Solutions (SSRS) (Media, PA) oversaw field operations, including pretesting of the questionnaire. Interviews were conducted from December 8 through December 27, although no calls were made over the Christmas holiday (December 24-26). Respondents completed an interview that included approximately 50 closed-ended questions about their response to a hypothetical scenario in which cases of inhalation anthrax are discovered without an identified source and the entire population of their city or town is asked to obtain prophylactic antibiotics from local dispensing sites within a 48-hour period. Efforts were made to ask questions in an order that reduced social desirability bias in terms of compliance. (The full questionnaire and scenario description can be found at www.liebertonline.com/bsp).

Interviewers identified HSPH as the organization conducting the research, but they did not identify any government funders in order to prevent bias toward agencies referenced in the scenario. Interviewers also reassured respondents that the scenario was hypothetical and that researchers had no information about an actual attack. SSRS provided an 800-number call line for any respondents who nonetheless became concerned. Five people called this line, but none were concerned about anthrax attacks.

This study used polling as a model methodology for reaching target populations during a crisis because the turnaround time is quicker than many other survey techniques and can therefore be replicated in a real crisis. The relatively short field time could reduce recall problems for respondents and deliver results to policymakers in a timeline that facilitates rapid changes in response or communication.^27,32 Although polls generally have lower response rates than longer-term surveys, research suggests that the resultant data are comparable to data from higher-response surveys conducted over longer periods of time when reweighted to key demographics.³³ Weighting addresses differential nonresponse across demographic groups, although it may not fully adjust for this possibility. In this poll, response rates were 13% nationally and 19% regionally. National and regional data were weighted separately to match the following known population parameters: gender, age, race, education, homeownership, phone status, metropolitan status, and U.S. Census region (national sample) or state (regional samples). Parameters were taken from the U.S. Census Current Population Survey (national sample), the American Community Survey (regional samples), and the National Health Interview Survey (both).^34–36 Data were also adjusted to account for the probability of selecting a given person based on his or her cell and landline access as well as household size.

Comparisons between national and regional data focus on differences in the summary categories of, for example, “likely” (which includes “very likely” and “somewhat likely”). We used 2-tailed t-tests (Newman Keuls) that account for the use of weighted data and reduce the risk of false-positive results from multiple comparisons. Differences are considered significant using a conventional alpha level of 0.05. All statistically significant differences are shown in the tables, though only significant differences between national and regional data of at least 10 percentage points were considered to have practical implications for policy and are therefore mentioned in the text.

Results

Public's Response to Recommendations

Likelihood of Going to a Dispensing Site to Get Antibiotic Pills

If public health officials recommended that the public obtain antibiotic pills from a dispensing site in the event of an anthrax attack in their city or town, the vast majority of respondents (89%) said they would be likely to follow the recommendation to get the pills for themselves within 48 hours of the attack (including 65% who said “very likely” and 24% “somewhat likely”) (Table 1). Among parents, there was a similar pattern: Nearly all (91%) said they would be likely to get antibiotic pills for their children (73% “very likely” and 18% “somewhat likely”).

Table 1.

Public's Response to Recommendations to Go to a Dispensing Site to Get Antibiotic Pills and to Start Taking Them Right Away—National vs Regional Data

	National	DC Area	Mercer County	NYC Area
Likelihood of Going to a Dispensing Site
Likelihood that they would go to a dispensing site to get antibiotic pills for themselves within 48 hours of confirmed anthrax cases	(n=1,092)	(n=509)	(n=507)	(n=517)
Likely (very/somewhat)	89	89	88	87
Very likely	65	65	67	67
Somewhat likely	24	24	21	20
Not likely (not very/not at all)	10	10	11	13
Not very likely	6	7	7	8
Not at all likely	4	3	4	5
Likelihood that they would go to a dispensing site to get antibiotic pills for their children within 48 hours of confirmed anthrax cases (among parents)	(n=271)	(n=141)	(n=136)	(n=145)
Likely (very/somewhat)	91	94	97	99
Very likely	73	79	84	88^*
Somewhat likely	18	16	12	11
Not likely (not very/not at all)	8	3	3	1
Not very likely	3	1	1	—
Not at all likely	5	2	2	1
Views on whether they would still be “very” or “somewhat likely” to go to a dispensing site even if they had to wait in line for 30 min, 1 hr, or 2 hr (among those “very likely” to go in the first place^a)
30 minutes	(n=255)	(n=120)	(n=123)	(n=126)
Likely (very/somewhat)	97	98	99	99
Very likely	88	91	96	85
Somewhat likely	9	6	3	14
Not likely (not very/not at all)	3	2	1	—
Not very likely	1	2	1	—
Not at all likely	1	—	—	—
1 hour	(n=236)	(n=110)	(n=127)	(n=115)
Likely (very/somewhat)	97	98	97	96
Very likely	87	87	88	83
Somewhat likely	10	11	10	13
Not likely (not very/not at all)	3	2	3	4
Not very likely	1	—	3	3
Not at all likely	2	2	—	1
2 hours	(n=240)	(n=122)	(n=117)	(n=125)
Likely (very/somewhat)	94	97	95	84
Very likely	75	92^*	71	74
Somewhat likely	19	5^*	24	10
Not likely (not very/not at all)	6	2	5	16
Not very likely	4	2	5	5
Not at all likely	2	<0.5	—	12^*
Likelihood of Taking Antibiotic Pills Right Away
Percent who would start taking the antibiotic pills right away or hold onto them (among those “very” and “somewhat” likely to go get the pills for themselves)	(n=975)	(n=452)	(n=459)	(n=461)
Start taking the pills right away	57	59	58	53
Hold on to the pills until they knew for sure that they had truly been exposed	35	36	37	43
Hold on to the pills for the foreseeable future	4	2	2	1
Percent who would start giving their children the antibiotic pills right away or hold onto them (among parents “very” and “somewhat” likely to go get the pills for their children)	(n=248)	(n=131)	(n=129)	(n=142)
Start giving the pills to their children right away	60	52	56	50
Hold on to the pills until they knew for sure that their children had truly been exposed	36	43	38	45
Hold on to the pills for the foreseeable future	2	2	3	4

Statistically significantly different from respondents in the national area at the 95% significance level.

Asked of one-third of those “very likely” to go to a dispensing site within 48 hours to get pills for themselves.

Note: Summary categories (eg, very/somewhat) may not equal the sum of individual categories combined (eg, very plus somewhat) due to rounding. Individual categories may not total 100% due to rounding.

Most adults who initially said they were “very likely” to go to a dispensing site within 48 hours of an attack to get antibiotic pills for themselves would still be likely to do so if they had to wait in line for 30 minutes, 1 hour, or even 2 hours (Table 1). For example, most adults (94%) who would be “very likely” to go to dispensing sites in the first place said they would be likely to go to the dispensing sites even if they knew they had to wait in line 2 hours, with 75% who said they would still be “very likely” to go and 19% who said “somewhat likely.”

Likelihood of Taking Antibiotic Pills Right Away

Among those who were very or somewhat likely to get the pills for themselves, a little more than half (57%) would follow the advice of public health officials and start taking the pills right away. An additional third of the public likely to get pills from a dispensing site (35%) said they would hold on to the pills until they knew for sure that they had truly been exposed, and 4% said they would hold on to the pills for the foreseeable future. Among parents who were likely to go to a dispensing site to get antibiotic pills for their children, 60% would start giving their children the pills right away, 36% would hold on to the pills until they knew for sure that their children had been exposed, and 2% would hold on to the pills for the foreseeable future.

Barriers to Going to a Dispensing Site

Among adults who said they were not “very likely” to go to the dispensing sites to get antibiotic pills (including those who said they are “not very likely,” “not at all likely,” or “somewhat likely”), the most common “major reasons” for not going included factors related to worries about their physical safety, as well as their lack of confidence in public health officials to protect them and provide for them during the process (Table 2). Most commonly, adults who were not “very likely” to go to the dispensing sites said “major reasons” for their decision not to go included worries that officials would not be able to control crowds (44%), that they would be exposed to anthrax in the process (40%), and that there would not be enough pills (39%). Nearly the same fraction noted that they were worried about pill safety (37%) and that they would get pills from an alternative source (36%).

Table 2.

Barriers to Following Public Health Officials' Initial Recommendation to Go to a Dispensing Site During an Anthrax Attack, Among Those Not “Very Likely” to Go—National vs Regional Data

“Major reason” for not going among adults not “very likely” to go to dispensing sites	National (n=366)	DC Area (n=161)	Mercer County (n=143)	NYC Area (n=151)
Worried that officials will not be able to control crowds	44	43	41	55
Worried about being exposed to anthrax while at the dispensing site	40	29	39	48
Worried that there would not be enough antibiotic pills	39	45	38	43
Worried about the safety of the antibiotic pills, including side effects	37	37	36	51
Would wait to get antibiotic pills until sure exposed to anthrax	37	36	38	50
Able to get antibiotic pills from doctor or someone else instead	36	30	37	44
Think there would be no need because government is likely to have overblown the situation	27	36	25	32
If not sick by time news reported anthrax cases, would believe not exposed	25	23	17	30
Too late for antibiotic pills to be effective by time announced anthrax cases in news	25	17	19	29
Don't think antibiotic pills would be effective in preventing people from getting sick with anthrax	24	21	20	28
Don't think I/my child(ren) would be likely to get sick from anthrax	23	14	10^*	31
Difficult to get to dispensing site and back home	21	18	21	28
Would use antibiotic pills already have at home	13	14	14	17
Would have no one to care for children while went to dispensing site^a	14	1	6	25

Statistically significantly different from respondents in the national area at the 95% significance level.

Only among parents who would not be “very likely” to go to a dispensing site within 48 hrs to get antibiotic pills for themselves or their children (n=97, national; n=38, NYC; n=47, DC; n=32, Mercer County).

Other “major reasons” related to beliefs that going to the dispensing sites would not be necessary or effective. More than a third of these adults said they would wait until they were sure they had been exposed to anthrax (37%), while 25% said that if they were not sick by the time of news reports, they would not think they had been exposed, with the same fraction (25%) saying that it would be too late by that point anyway. About a quarter (27%) cited their belief that “the government would likely be overblowing the situation,” and 24% said they did not think the pills would be effective.

Concerns about logistics were cited by a relatively smaller share of these adults as “major reasons” for being less likely to go to the dispensing sites. Twenty-one percent of adults said it would be difficult to travel back and forth to the dispensing sites, and 14% of parents said there would not be anyone available to care for their children while they went.

Influences on Willingness to Follow Recommendations

Baseline Knowledge about Inhalation Anthrax

A majority of the public (61%) believed they were familiar with the term “inhalation anthrax” (20% “very familiar” and 41% “somewhat familiar”) (Table 3), while about one-third of the public (37%) said they were not familiar with the term (16% “not very familiar” and 21% “not at all familiar”). Among those who said they were “very” or “somewhat familiar” with the term “inhalation anthrax,” just over half (57%) believed the illness is not contagious, one-third (34%) believed that inhalation anthrax is contagious, and 9% did not know whether it is or not.

Table 3.

Attitudes and Knowledge that Could Influence Public's Willingness to Follow Public Health Officials' Recommendations—National vs Regional Data (percentage saying …)

	National	DC Area	Mercer County	NYC Area
Knowledge about Inhalation Anthrax
Familiarity with the term “inhalation anthrax”	(n=1,092)	(n=509)	(n=507)	(n=517)
Familiar (very/somewhat)	61	73^*	70^*	56
Very familiar	20	31^*	28^*	21
Somewhat familiar	41	42	42	35
Not familiar (not very/not at all)	37	27^*	30	44
Not very familiar	16	14	15	21
Not at all familiar	21	13^*	15	22
Belief about contagiousness (among those saying “very” or “somewhat familiar”)	(n=692)	(n=397)	(n=373)	(n=335)
Believe inhalation anthrax is contagious	34	23^*	28	32
Do not believe inhalation anthrax is contagious	57	70^*	60	55
Do not know if inhalation anthrax is contagious	9	8	12	12
Belief about likelihood of serious illness or death if exposed to anthrax and not treated	(n=1,092)	(n=509)	(n=507)	(n=517)
Likely (very/somewhat)	90	91	90	88
Very likely	66	66	69	67
Somewhat likely	24	24	22	21
Not likely (not very/not at all)	6	8	8	7
Not very likely	3	4	5	3
Not at all likely	3	3	2	4
Concern about Inhalation Anthrax
If heard or saw in the news that there were cases of anthrax due to an attack in their city or town…
Level of worry about becoming seriously ill or dying	(n=1,092)	(n=509)	(n=507)	(n=517)
Worried (very/somewhat)	83	79	86	85
Very worried	46	37^*	44	51
Somewhat worried	36	42	42	33
Not worried (not very/not at all)	16	21	14	15
Not very worried	10	14	8	10
Not at all worried	6	7	7	5
Views of Pill Safety and Efficacy
Views on whether the antibiotic pills used to treat anthrax would be safe to take	(n=1,092)	(n=509)	(n=507)	(n=517)
Safe (very/somewhat)	82	89^*	90^*	83
Very safe	31	37	42^*	35
Somewhat safe	51	52	48	49
Not safe (not very/not at all)	15	8^*	7^*	14
Not very safe	9	5	4^*	9
Not at all safe	5	3	3	5
Views on whether the antibiotic pills used to treat anthrax would be effective in preventing them from becoming seriously ill or dying if exposed to anthrax	(n=1,092)	(n=509)	(n=507)	(n=517)
Effective (very/somewhat)	85	89	86	85
Very effective	30	28	35	32
Somewhat effective	55	61	51	53
Not effective (not very/not at all)	10	9	11	11
Not very effective	7	5	7	7
Not at all effective	3	4	4	3
Confidence in Government's Response
That there would be a sufficient supply of antibiotic pills for everyone in city or town who wanted them	(n=1,092)	(n=509)	(n=507)	(n=517)
Confident (very/somewhat)	63	62	66	60
Very confident	18	16	22	16
Somewhat confident	45	45	44	44
Not confident (not too/not at all)	36	37	33	38
Not too confident	25	27	26	31
Not at all confident	11	10	7	8
In ability of federal public health agencies to deliver antibiotics to local and state public health agencies	(n=1,092)	(n=509)	(n=507)	(n=517)
Confident (very/somewhat)	56	58	61	58
Very confident	14	13	15	11
Somewhat confident	42	45	46	47
Not confident (not too/not at all)	42	41	38	41
Not too confident	31	32	29	31
Not at all confident	11	9	10	10
In ability of local and state public health agencies to deliver antibiotics to the public	(n=1,092)	(n=509)	(n=507)	(n=517)
Confident (very/somewhat)	63	66	68	65
Very confident	19	16	16	14
Somewhat confident	43	50	52	51
Not confident (not too/not at all)	36	33	32	34
Not too confident	27	24	26	26
Not at all confident	8	9	5	8

Statistically significantly different from respondents in the National Area at the 95% significance level.

Ninety percent of adults believed that it would be either “very likely” (66%) or “somewhat likely” (24%) that they would become seriously ill or die if they were exposed to anthrax and did not get any medical treatment, while 6% believed this outcome would be “not very” or “not at all likely.”

Concern about Inhalation Anthrax

The vast majority of respondents (83%) said they would be worried about themselves becoming seriously ill or dying if they received news of an anthrax attack in an unknown location in their city or town. This fraction included nearly half (46%) who said they would be “very worried” and 36% who would be “somewhat worried.” A small minority of respondents (16%) said that they would be “not very worried” or “not at all worried” after hearing news of an anthrax attack.

Views of Pill Safety and Efficacy

When asked about their predicted perceptions of the antibiotic pills, the vast majority of the public (82%) believed that the pills would be safe to take. This share included a minority (31%) who said the pills would be “very safe,” while the majority (51%) said they would be “somewhat safe.” Similarly, a majority of the public (85%) believed that the pills would be effective in treating anthrax, with 30% who believed they would be “very effective” and 55% who believed they would be “somewhat effective.”

Confidence in Government's Response

Nearly two-thirds of the public (63%) were confident that there would be a sufficient supply of the antibiotic pills for everyone in their city or town who wanted them, while one-third (36%) were not confident. Likewise, nearly two-thirds of the public (63%) were confident that their local or state public health agency would be effective in getting the pills to those in the public who wanted them, leaving about a third (36%) who were not confident. Approximately half (56%) were confident that federal public health agencies would be able to deliver the pills in time to their local or state public health agency, while 42% were not confident of that.

Trusted Information Sources

Sources of Information for Logistical Information

The public would be most likely to turn to their state and local public health departments (88% likely, including 54% “very likely,” 35% “somewhat likely”), television news (79% likely, including 45% “very likely,” 35% “somewhat likely”), and online news (75% likely, including 46% “very likely,” 30% “somewhat likely”) to get information about dispensing sites or the process of getting the antibiotic pills (please note that for clarity, only the summary response category of “very likely” and “somewhat likely” is shown in Table 4). Other likely sources of information included police departments (70% likely, including 38% “very likely,” 32% “somewhat likely”) and fire departments (68% likely, including 41% “very likely,” 27% “somewhat likely”). A similar percentage of the public would be likely to use local newspapers (69% likely, including 28% “very likely,” 41% “somewhat likely”), local radio (64% likely, including 33% “very likely,” 31% “somewhat likely”), or city hall (63% likely, including 27% “very likely,” 36% “somewhat likely”) to access this information.

Table 4.

Public Preferences for Information and Trust in Government Officials as Sources of Reliable Information in an Anthrax Attack—National vs Regional Data

Sources of information to learn more about dispensing sites or the process of getting the antibiotic pills (percentage saying “very likely” or “somewhat likely” to turn to each source)	National	DC Area	Mercer County	NYC Area
Local or state public health department, either by telephone or website^a	88	85	87	89
Local TV news^a	79	80	76	79
Websites of local newspapers or TV stations^b	75	81	75	74
Police department, either by telephone or website^a	70	63	71	65
Fire department, either by telephone or website^b	68	60	63	68
Local newspapers^a	69	68	77	72
Local radio^b	64	69	66	68
City Hall, either by telephone or website^b	63	57	64	65
Trust in federal government officials as a source of reliable information about whether or not to go to the dispensing sites and take the antibiotic pills^c (percentage saying trust “a lot” or “some”)	(n=532)	(n=251)	(n=250)	(n=263)
Director of the Centers for Disease Control and Prevention	77	85	84	80
Secretary of the Department of Health and Human Services	69	77	72	76
President of the United States	65	82^*	77^*	82^*
Trust in local and state government officials as a source of reliable information about whether or not to go to the dispensing sites and take the antibiotic pills^d (percentage saying trust “a lot” or “some”)	(n=560)	(n=266)	(n=215)	(n=244)
Director of their state or local public health department	71	72	75	69
Governor of their state	64	65	68	64
Mayor of their city or town	63	60	74	64

Asked of about one-half of respondents (n=547 national, n=252 NYC, n=250 DC, n=261 Mercer County).

Asked of about one-half of respondents (n=545 national, n=265 NYC, n=259 DC, n=246 Mercer County).

Asked of about one-half of respondents (n=532 national, n=251 NYC, n=250 DC, n=263 Mercer County).

Asked of about one-half of respondents (n=560 national, n=266 NYC, n=215 DC, n=244 Mercer County).

Statistically significantly different from respondents in the National Area at the 95% significance level.

Government Officials as Reliable Sources of Information

A majority of the public said they would “trust” each of the proposed federal and local or state government officials asked about in this study “as a source of reliable information about whether or not to go to the dispensing sites and take the antibiotic pills.” On a federal level, 77% of adults would trust the Director of the Centers for Disease Control and Prevention (CDC) (46% “a lot,” 31% “somewhat”), 69% would trust the Secretary of the Department of Health and Human Services (33% “a lot,” 36% “somewhat”), and 65% would trust the President of the United States (38% “a lot,” 27% “somewhat”). On a local and state level, 71% of the public said they would trust the director of their state or local health department (38% “a lot,” 34% “somewhat”), 64% would trust the governor of their state (35% “a lot,” 29% “somewhat”), and 63% would trust the mayor of their town (30% “a lot,” 33% “somewhat”).

Differences Between National and Regional Results

In general, people living in areas where anthrax attacks occurred in 2001 had responses similar to those of the nation as a whole; however, there were a few differences in responses, highlighted here.

Few differences existed between the regions and the national sample in likelihood of going to a dispensing site and in tolerating wait times (Table 1). The proportions of adults who identified specific barriers as being “major reasons” for not going to the dispensing sites were also similar between regions compared to adults nationally (Table 2). The only exception was that fewer adults in Mercer County, NJ, than adults nationally said a “major reason” for not going to a dispensing site was not thinking they or their children would be likely to get sick from anthrax (10% vs 23%).

Knowledge and concern about inhalation anthrax differed among adults in some regions compared to adults nationally (Table 3). Adults from the DC area were more likely than adults nationally to say they were “familiar” with the term “inhalation anthrax” (73% in DC vs 61% nationally). Among those saying they were familiar with the term, adults from the DC area were more likely than adults nationally to say that they do not believe anthrax is contagious (70% vs 57%).

Sources that people would turn to for information about logistics did not vary by region (Table 4). However, trust in federal government officials and others as “sources of reliable information about whether or not to go to the dispensing sites and take the antibiotic pills” varied among adults in some regions compared to adults nationally. More adults in each region as compared to adults nationally said they would trust the President of the United States “a lot” or “some” (82% in DC, 77% in Mercer County, and 82% in NYC area vs 65% nationally).

Discussion

Findings from this poll provide important signs of public willingness to comply with public health recommendations for obtaining mass antibiotic prophylaxis in the event of an anthrax attack. After seeing media reports about cases of inhalation anthrax from an unidentified source in their city or town, the majority of Americans nationwide would be worried about getting ill personally and say they would follow public health officials' recommendations to go pick up antibiotic prophylaxis for themselves and for their children at dispensing sites set up in convenient locations. Moreover, those who were committed to going would not be severely deterred by wait times up to 2 hours.

Although most Americans would pick up prophylactic antibiotic pills at dispensing sites, results from this poll indicate that public health officials may face several challenges to compliance during an attack. First, sizable fractions of the public who are less likely to go to sites hold potentially compelling reasons for not going, including fears about their personal safety in crowds and a lack of confidence in federal and local/state government agencies to provide appropriate protection or to provide sufficient supplies. These data suggest there is an underlying level of distrust in public health officials at all levels among fractions of the public, particularly as relates to their competence and perhaps their “fiduciary responsibility.” This is consistent with other literature in the field.^17,19–21 Trust in public officials may need to be enhanced not only at the time of a crisis, but also over a longer time leading up to a crisis.¹⁰ It is notable that interviews were conducted for this study during the federal and state/local government's 2009 H1N1 influenza vaccine distribution efforts. Data concerning mass prophylaxis programs in this study may therefore reflect public views of government H1N1 vaccination efforts to some degree. However, this is not a limitation of the study, but rather a reality that public officials would need to address in a real crisis if it occurred in the near term.

Second, among the population as a whole, relatively small fractions are “very” confident in the government's ability to provide sufficient supplies or believe the pills would be “very” safe or effective. The fraction of people in these “very” categories may be an important indicator of those who are more committed to their perspective and may be more predictive of behavior, as suggested by the political science literature^37–40 as well as public health literature that uses polling data to assess public compliance with public health recommendations in a crisis.⁴¹ Conversely, those in the “somewhat” categories may be more vulnerable to changes of opinion. Thus, in a real bioterrorist attack, rumors could help sustain underlying concerns among the fraction of the responders who are less certain about how they would react as well as those who already believe the pills are unsafe or have less confidence in the government. This could increase public resistance to going to dispensing sites, so public communications efforts should therefore address these issues directly.

Third, substantial portions of the public hold misinformation about the contagiousness of inhalation anthrax; this could exacerbate resistance to going to dispensing sites and simultaneously trigger more widespread concern about being near people who may have been exposed. Such concerns may put people who are thought to have been exposed at risk of mistreatment, as happened in the severe acute respiratory syndrome (SARS) outbreak, for example.^42,43 Care needs to be used in describing people who may be more likely to have been exposed in order to minimize discrimination.

Fourth, poll results suggest that some people may believe traditional health resources, including their doctor's office or pharmacy, would be able to deliver prophylaxis in a crisis. Public health officials will need to use trusted information sources to deliver messages to the public that such health providers may not have the resources to deliver prophylactic treatment during a crisis. Public health officials will also need to develop a partnership with clinicians to warn them of potential patient overload and to create shared information and triage systems for redirecting people who seek out limited resources during an attack.

Finally, poll results show that a substantial share of people who would go to the dispensing sites would not actually consume the pills. Communications at dispensing sites may need to emphasize taking the pills, and dispensing site operations personnel may need to consider materials, such as water, that would facilitate the process. The sizable share that would “wait until they knew they had been exposed” and the fraction of those who would not go at all until they “knew they had been exposed” suggests an overriding need to clearly communicate the urgency of taking antibiotics quickly—before symptoms appear—as well as the dangers of a “wait and see” approach.

To reach the public with logistics information about dispensing sites during an anthrax crisis, local news (including online) and public health resources are key. Police and fire departments play an important secondary role in communication. While the public has trust in an array of leaders at the state and national levels to serve as information sources, public health officials at the CDC may be most trustworthy when considering national organizations, while local/state public health departments may be most trustworthy among state and local organizations. This is consistent with other data suggesting that public health officials are generally more trustworthy than political figures in times of public health crises.^44,45

The few differences between regions and the national sample suggest there may be few lasting effects that are relevant to this specific type of anthrax attack in the areas where the 2001 attacks occurred. Even differences that did exist in these data, such as variations in trust in government officials as reliable information sources, may reflect more contemporary views of current office holders or be a function of demographic differences between the areas rather than past experience. This is not to say that individuals or smaller populations, such as those directly exposed to anthrax in 2001, may not have lasting effects from their past experience, but rather that the attitudes of each of these regions as a whole do not warrant dramatically different approaches for the general population than would be used in other areas. Public health officials in charge of regional efforts may do well to consider the specific and evolving beliefs and attitudes of their communities in planning responses.

The findings from this study are subject to at least 3 limitations. First, the poll focuses on participants' responses to a hypothetical scenario, which may differ from the real-life circumstances and media description of any future attacks. Nonetheless, the goal of the study is to provide broad insights about the public's general response to key dimensions of a mass prophylaxis program, not to provide an exact prediction of public response under a very specific scenario. For this reason, we used a scenario that is somewhat general in nature, and the questions highlight areas of concern that may be applicable to a wider array of specific scenarios. This approach has been useful in other tabletop planning exercises.^22,46

Second, the length of the questionnaire prevented us from asking additional questions that might be helpful, such as whether people would be willing to wait longer than 2 hours to get prophylactic antibiotics at a dispensing site.

Finally, the sample size did not permit in-depth assessment of several factors that may be associated with willingness to take antibiotic prophylaxis, including personal characteristics such as racial/ethnic background or socioeconomic status. Given that racial/ethnic minority communities and lower socioeconomic groups in the United States are often disproportionately affected during public health crises, there is a need for additional research in this area to ensure that outreach and support is targeted effectively to these higher-risk groups.^47–49 Nonetheless, the findings from this study may provide key guidance for programs planning for and responding to possible anthrax attacks and similar kinds of bioterrorism attacks in the areas of both communication and operations.

Footnotes

Acknowledgments

The authors are grateful for the assistance of Sue Gorman, PharmD, MS, Associate Director for Science, Division of Strategic National Stockpile. This poll is funded as part of a project under a cooperative agreement between the Harvard School of Public Health, the Centers for Disease Control and Prevention (CDC), and the National Public Health Information Coalition (NPHIC). None of the authors have potential conflicts of interest to declare.

*

CRI also includes a follow-up program to provide an additional 50-day supply later, but this element of the program is not described in this study.

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