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Potential Bioterrorism-Related Incidents: Analyzing Predictors for requesting CDC DPEI/EPRB Assistance, 2007-2009

Research Article ºÚÁÏÍø
Geroncio C. Fajardo*, Joseph Posid and Konrad Hayashi
Division of Preparedness and Emerging Infections, National Center for Emerging and Zoonotic Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, USA
*Corresponding authors: Geroncio C. Fajardo
Epidemiologist, Emergency Preparedness and Response Branch
Division of Preparedness and Emerging Infections
National Center for Emerging and Zoonotic Infectious Diseases
Centers for Disease Control and Prevention
1600 Clifton Rd NE, MS C-18
Atlanta, GA 30333, USA
E-mail: geronciofajardo@yahoo.com
 
Received March 22, 2012; Published July 25, 2012
 
Citation: Fajardo GC, Posid J, Hayashi K (2012) Potential Bioterrorism-Related Incidents: Analyzing Predictors for requesting CDC DPEI/EPRB Assistance, 2007- 2009. 1: 159. doi:10.4172/scientificreports.159
 
Copyright: © 2012 Fajardo GC, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
 
Abstract
 
Background/Objectives: When an agency or an individual reports a potential bioterrorism-related incident to the United States Centers for Disease Control and Prevention (CDC), request types for CDC Division of Preparedness and Emerging Infections, Emergency Preparedness and Response Branch (DPEI/EPRB) assistance may include clinical consults, laboratory consults, laboratory testing of samples, and epidemiologic consults. The CDC DPEI/EPRB also provides situational awareness to leadership of requests for CDC assistance using either a Situation Report (SITREP) or an Incident Notice (IN). We analyzed predictors for requesting assistance from CDC DPEI/EPRB.
 
Methods: Using information obtained from SITREPs or INs prepared by CDC DPEI/EPRB from January 2007 to December 2009, we conducted descriptive and bivariate statistics to investigate relationships among the following selected variables: request for CDC DPEI/EPRB assistance, reporting agency, incident type, time of notification, and season. We also performed binomial regression analyses to analyze predictors for requesting CDC DPEI/EPRB assistance.
 
Results: Among the 123 incidents in this study, 55.3% (n=68) requested CDC DPEI/EPRB assistance. Bivariate analysis showed significant statistical relationships among the variables (p<0.05) except for that between request for CDC DPEI/EPRB assistance and season (p=0.285). However, binomial logistic regression models indicated that incident type and reporting agency were the only significant predictors for requesting request for CDC DPEI/EPRB assistance.
 
Conclusions: Findings from this study may allow managers of State and Local public health departments to model the demands on their staff’s time and adjust work schedules more efficiently. This could maximize the impact of financial and human resources when the need arises to provide assistance during potential bioterrorism-related incidents or other events of public health significance. Furthermore, results from this study could have comparable policy implications for other levels of federal, state and local government.
 
Keywords
 
Request for CDC DPEI/EPRB assistance; Reporting agency; Incident type; Time of notification; Season
 
Introduction
 
The Centers for Disease Control and Prevention (CDC) Division of Preparedness and Emerging Infections, Emergency Preparedness and Response Branch (DPEI/EPRB) of the National Center for Emerging and Zoonotic Infectious Diseases (NCEZID), Office of Infectious Diseases (OID), is responsible for providing 24/7 on-call services and situation awareness for acts, or threatened acts, of bioterrorism (BT) or other large-scale events with infectious disease implications. CDC DPEI/EPRB may receive the call from CDC’s Emergency Operations Center (EOC) and manage the response, but CDC DPEI/EPRB assistance could be provided primarily by a Subject Matter Expert (SME) in another CDC program (Figure 1). Documentation of the interactions between CDC DPEI/EPRB and requestors are recorded on a written Situation Report (SITREP) or Incident Notice (IN). These documents are submitted to the CDC EOC for distribution to internal CDC and other external government entities on a need-to-know basis.
 
Figure 1: CDC DPEI/EPRB Basic SITREP/IN Protocol Flowchart.
 
Many incidents have the potential to involve many federal/state/ local government or private agencies and utilize various amounts of resources. Thus, CDC EOC and DPEI/EPRB have maintained a list of the partners who could provide the necessary subject matter expertise and other resources when any kind of assistance is requested in responding to a particular type of bioterrorism-related incident.
 
This paper conducted statistical analysis to determine relationships among SITREP/IN variables, and it also evaluated selected SITREP/ IN covariates for the outcome variable “request for CDC DPEI/EPRB assistance” to better predict conditions when CDC assistance was needed.
 
Methods
 
The authors reviewed all SITREPs and INs prepared by CDC DPEI/EPRB from January 2007 through December 2009. Although a SITREP or IN may have had one or more updates, it was only counted as one incident for purposes of this study.
 
Request for CDC DPEI/EPRB assistance was coded as a dichotomous outcome variable (CDC DPEI/EPRB assistance requested or no CDC DPEI/EPRB assistance requested) while the covariates were coded as categorical variables or dichotomous variables when appropriate. The authors coded the calls/types of incidents that DPEI/EPRB received into three groups: BioWatch, unknown powder/suspicious package, other. Potential bioterrorism-related incidents were coded such that powder-related event was used as the reference category in performing logistic regression analysis.
 
Agencies reporting the incidents were coded into four groups: state, local, federal, and other. “Federal” agencies included U.S. Department of State, Department of Labor, US Coast Guard, Department of Justice, FBI, Department of Homeland Security, Department of Defense and others. “State” agencies referred to state departments of health. Local agencies referred to county/city departments of health or other substate level organizations. “Other” agencies included private hospitals, private physician, a commercial airline, a national professional organization, an international agency, and others. Reporting agency was coded such that federal agency was used as the reference category in logistic regression analysis.
 
Time of notification (i.e., time incident was reported to DPEI/ EPRB) was coded as a dichotomous variable (during office hours or outside office hours). Incidents reported during office hours refer to calls received between 8:00 a.m. and 4:30 p.m. [Eastern Standard Time (EST)] on weekdays (Monday-Friday). A call received on Saturday or Sunday was considered a call outside office hours.
 
The season variable was created using dates of events or CDC DPEI/ EPRB notifications which were coded based on the calendar months: fall (September, October, November); winter (December, January, February); summer (June, July, August); and spring (March, April, May). Season was coded such that summer was used as the reference category in logistic regression analysis.
 
Statistical crosstabs were performed to determine frequency distribution of the variables and to generate information about bivariate relationships between: 1) request for CDC DPEI/EPRB assistance and type of incident, 2) request for CDC DPEI/EPRB assistance and reporting agency, 3) request for CDC DPEI/EPRB assistance and time of notification, and 4) request for CDC DPEI/EPRB assistance and season. To take into account the possible effect of a third variable on the relationship between the other two variables, the third variable was controlled by making separate crosstabulations for each level of the third variable.
 
Binomial logistic regression analysis was also performed to predict requests for CDC DPEI/EPRB assistance. Odds ratios were interpreted and the p-values of the logistic regression coefficients were compared to a critical value of 0.05 to determine which of the covariates contributed significantly to the outcome. When a predictor variable did not contribute significantly to the full model, another binomial logistic regression analysis was performed to enter only those variables that were significant covariates to the outcome. The authors used the Omnibus Test of Model Coefficients as the overall test of the logistic regression model. This is a test of the null hypothesis that adding the predictor variables to the model has not significantly increased our ability to predict requests for CDC DPEI/EPRB assistance whenever an incident is reported to CDC DPEI/EPRB. The probability of obtaining the chi-square statistic given that the null hypothesis was true was then compared to a critical value of 0.05 to determine if the overall model was statistically significant. Data elements from SITREPs and INs were entered into an electronic database created using Access 2003 [1]. Entries in the database were cleaned and ascertained by reviewing and verifying all of the information against hardcopies of all documents. SPSS 17.0 [2] and SAS 9.2 [3] were used for data evaluation and statistical analyses.
 
Results
 
Within this three-year period, CDC DPEI/EPRB prepared SITREPs and INs in response to 123 potential bioterrorism-related incidents. Table 1 shows that considering all incident types, reporting agencies, time of notification and season, 55.3% (n = 68) of the calls requested CDC DPEI/EPRB assistance while 44.7% (n = 55) did not ask for CDC DPEI/EPRB assistance.
 
Table 1: Data abstracted from 123 SITREPs/INs prepared by CDC DPEI/EPRB, 2007-2009.
 
Table 1 also shows that 39.8% (n = 49) dealt with unknown powder, 34.2% (n = 42) involved BioWatch issues, and 26.0% (n = 32) were related to other incidents. Further stratification of the data shows that powderrelated incidents were reported by all reporting agencies of which 31 out of 49 were reported by federal agencies. All BioWatch-related incidents were reported only by state and local agencies, and they were determined to be associated with naturally-occurring environmental contamination. Other incidents were reported by all reporting agencies of which 15 out of 32 were reported by other agencies.
 
Of the 68 incidents requesting CDC DPEI/EPRB assistance, 22.8% (n=28) were from federal government agencies, 10.6% (n=13) were from state government agencies, 11.4% (n=14) were from local government agencies (county/city), and 10.6% (n=13) were from other agencies. Further data analysis showed that 38.2% (n=26) were for laboratory analyses of samples, 30.9% (n=21) were for laboratory consults that primarily involved discussions of test results, 23.5% (n=16) were for clinical consults, and 7.4% were for other types of assistance.
 
 
Table 1 shows that 37.4% (n=46) were reported to CDC DPEI/EPRB during office hours while 62.6% (n=77) were reported outside office hours. The majority of calls reported during office hours requested CDC DPEI/EPRB assistance (32 out of 46) and less than half of the incidents reported outside office hours requested CDC DPEI/EPRB assistance (36 out of 72). Further evaluation of the 77 calls reported outside office hours indicated that a large number of them (n=41) involved BioWatch-related issues and that 24 out of these 41 incidents did not request CDC DPEI/EPRB assistance. Of the 46 incidents reported during office hours, most of them involved powder-related issues (n=34) and 24 out of 34 requested CDC DPEI/EPRB assistance.
 
The highest number of reported incidents occurred during the summer months (n=35, 28.5%) while the lowest number of reported incidents occurred during the spring months (n=23, 18.7%) (Table 1). During the fall months and compared to each of the other seasons, further data analysis indicated that BioWatch-related incidents were most commonly reported.
 
As indicated in Table 1, SPSS 17.0 crosstabs procedure (bivariate analysis) showed statistically significant relationships between request for CDC DPEI/EPRB assistance and type of incident (p=0.025), between request for CDC DPEI/EPRB assistance and reporting agency (p< 0.001), and between request for CDC CPEI/EPRB assistance and time of notification (p=0.014). There was no statistically significant relationship between request for CDC DPEI/EPRB assistance and season (p=0.285).
 
A test of the full binomial logistic regression model (Omnibus Test of Model Coefficients) was statistically significant, X2(9, N=123) = 25.519, p=.002. However, type of incident and reporting agency were the only significant predictors for requesting CDC DPEI/EPRB assistance. In addition, the model was able to correctly classify 70.6% of those that requested CDC DPEI/EPRB assistance and 67.3% of those that did not, for an overall success rate of 69.1%.
 
Table 2 shows the final logistic regression model using only the two significant covariates (type of incident and reporting agency) in relation to request for CDC DPEI/EPRB assistance. Compared to the full model, a test of this model was also statistically significant, X2(5, N=123) = 21.935, p=.001. In addition, this model was also able to correctly classify 70.6% of those that requested CDC DPEI/EPRB assistance and 72.7% of those that did not, for an overall success rate of 71.5% which was slightly higher than the full model.
 
Table 2: Final binomial logistic regression model (two significant predictor variables).
 
Discussion
 
CDC DPEI/EPRB was the designated organizational unit that was first contacted by CDC EOC when there were reported unknown white powders, BARs, or other potential BT-related threats or risks out in the community. It established a protocol to respond to requests for CDC DPEI/EPRB assistance to promote standardized information collection, analysis, decision-making, and reporting.
 
Descriptive statistics
 
The majority of the incidents reported to CDC DPEI/EPRB during the study period requested some type of assistance. Requests for CDC DPEI/EPRB assistance included laboratory analysis of unknown powder for the presence of biological threat agents, interpretation of laboratory results, review of BioWatch screening results for airborne pathogens, clinical consults (such as assistance in identifying rashes), consult on patient/environmental management, diagnostic support, therapeutic support, epidemiologic support, and management of smallpox vaccination adverse event.
 
Compared to other reporting agencies, federal agencies reported the highest number of potential bioterrorism-related incidents as well as the highest number of requests for CDC DPEI/EPRB assistance which could be attributed to a large number of powder-related incidents that they reported. Unknown powder or suspicious package incidents raised a high suspicion for anthrax bioterrorism agents because of the anthrax-related mailings on October 9, 2001 that increased public and governmental awareness of the threat of terrorism using biological weapons [4-6]. Unknown substances (usually called “White Powder” incidents) were reported regularly, and prompt evaluation of these substances was critical in evaluating potential danger to those exposed to any hazardous substances in the powders. It could be this high suspicion for anthrax bioterrorism agent and the need for prompt evaluation of this powder-related incident that triggered the need for CDC DPEI/EPRB assistance, mostly in the form of laboratory testing.
 
The slightly fewer number of calls that CDC DPEI/EPRB received from “State and local health departments” compared to federal agencies were primarily due to BioWatch-related incidents and with less number of calls for powder-related incidents. The fact that there were fewer powder-related calls seemed logical because CDC DPEI/EPRB protocol stated that if the EOC was called, and the caller was a practicing physician or came from a local/regional health department reporting incidents other than a BioWatch-related issue, the caller was referred to their State health department first. If the State health department could not resolve the inquiry, the State would then contact CDC DPEI/EPRB requesting consultation or other assistance. CDC DPEI/EPRB did not directly investigate unknown substances unless requested by State, Local, Tribal and Territorial (SLTT) governments after they had done initial evaluations. Unknown substances first underwent a threat assessment by law enforcement. If the unknown substance was determined to be threatening, the local HAZMAT/Emergency Response performed initial screening for chemicals, radiation or explosives. After that, the substance was sent to the nearest Laboratory Response Network (LRN) [7] laboratory for screening per LRN protocols. The CDC DPEI/EPRB on-call person would facilitate linking the reporting entity with their local resources to manage the event.
 
Further analysis of BAR-related incidents in this study indicated that all of these incidents were reported by state/local government jurisdictions, that almost all of them were reported outside CDC DPEI/EPRB’s office hours, that most of them did not request for CDC DPEI/EPRB assistance, and that most of them occurred in the fall and winter. In the event of a BAR where the presence of DNA of an organism screened for by the BioWatch program was detected by a laboratory, CDC DPEI/EPRB was responsible for rapidly assessing and evaluating information from the reporting organizations and other data sources to properly assess risks to public health, and for CDC DPEI/ EPRB to expediently extend assistance to the requesting organization. The BioWatch Program was deployed in 2003 by the Department of Homeland Security (DHS) to provide early warning of a biological weapon attack [8-11]. Following the DHS guideline, the reporting state or local government may or may not request for CDC DPEI/EPRB assistance.
 
Examples of “other” types of potential bioterrorism-related incidents that CDC DPEI/EPRB responded to in this study included: suspected smallpox; any confirmed or suspected biological agent being used to incite terror, threaten or cause harm; lab incident involving any Category A agent [12]. Most of these reported incidents requested CDC DPEI/EPRB assistance.
 
Our study could not evaluate the importance of potential bioterrorism-related incidents reported by physicians and other institutions since protocol advised local callers to contact their State health department before a call was made directly to CDC DPEI/EPRB. There is no doubt that hospital emergency departments and outpatient centers will play a crucial role in the response to an act of bioterrorism, and the first victims of a bioterrorist attack will probably be identified by physicians or other primary health-care providers (doctors’ offices, clinics, and emergency rooms). Thus, specific response plans from these institutions should also be prepared in collaboration with local health departments.
 
The majority of the calls reported during office hours requested CDC DPEI/EPRB assistance and most of them involved unknown white powder in letters or suspicious packages. This could be due to the fact that these letters or suspicious packages were delivered and opened during office hours and assistance was requested because the threat of anthrax exposure had always been considered a significant potential threat that needed an urgent response from various emergency responders. In contrast, majority of the calls reported outside office hours did not request CDC DPEI/EPRB assistance. This was due to the fact that most of the incidents that were reported outside office hours were incidents related to BioWatch issues (laboratory tests for BioWatch filters were routinely collected for analysis at the end of the day). Although many BAR-related incidents did not result in request for CDC DPEI/EPRB assistance, the affected jurisdictions had to report the incident in accordance with the DHS protocol. Even though some incidents were reported outside office hours, CDC DPEI/EPRB assistance was available when requested.
 
Both the absolute number of events and the proportion of all events in which CDC DPEI/EPRB’s assistance was requested was highest during summer months. The fewest reports occurred in the spring, but the lowest proportion of requests for assistance (as a function of the number of reports received during any season) occurred in the winter months. This study does not provide an understanding of seasonal variation of reports although seasonal variations for some potential bioterrorism agents were known [13-15].
 
Analytic statistics
 
Statistically significant bivariate relationships were noted. When controlling for a third variable for these significant relationships, however, crosstabs output showed that some of the cells had expected frequencies less than 5. This indicated that one of the assumptions of chi-square had been violated and thus, the results obtained when controlling for the third variable might not be meaningful.
 
Our logistic regression models suggested that “incident type” and “reporting agency” were the only two significant covariates for the outcome variable “request for CDC DPEI/EPRB assistance. “ When holding all other variables constant, the logistic regression models showed that federal agencies reporting potential bioterrorism-related incidents were more likely to request CDC DPEI/EPRB assistance compared to state, county/city or other agencies. This was confirmed by the fact that compared to each of the other reporting agencies, federal agencies reported a large number of powder-related incidents that requested CDC DPEI/EPRB assistance in relation to the total number of powder-related incidents. When holding all other variables constant, the models showed that other incidents and BioWatch-related incidents were more likely to request for CDC DPEI/EPRB assistance.
 
The finding in the logistic regression model that BioWatch events were not significantly more likely to result in a request for CDC DPEI/EPRB assistance compared to powder-related incidents seemed confusing at first because when reporting agency was not considered, it looked like powder-related incidents were more likely to request CDC DPEI/EPRB assistance compared to BioWatch-related incidents. As mentioned previously, however, BioWatch incidents during this study period were reported to CDC EOC by state or local agencies only as prescribed by notification protocols. When analyzing both BioWatch and powder-related incidents at the state and local levels only, we then observed that BioWatch incidents were indeed more likely to request CDC DPEI/EPRB assistance compared to powder-related incidents. The lack of meaningful interpretation of such finding in the logistic regression model, i.e. not statistically significant p-value, could then be explained by the fact that BioWatch events were not reported by all four categories of reporting agency. In fact, when running logistic regression analysis between the outcome variable and incident type stratified by reporting agency, the logistic regression models for federal agency and other agency did not include odds ratios for BioWatch versus powder. It did not make sense to evaluate request or no request for CDC DPEI/ EPRB assistance for white powder incidents reported by federal and other agencies and then compare it to BioWatch incidents that were never reportable by federal or other agencies in the first place.
 
“Other” types of potential bioterrorism-related incidents that were reported to CDC DPEI/EPRB were significantly more likely to result in a request for CDC DPEI/EPRB assistance compared to powder-related incidents. These incidents required specific, specialized knowledge to address an urgent concern of the local/state or federal agency requesting assistance. Incidents in this category were related to Brucella positive sample, laboratory worker potential exposure to B. anthracis, monkey pox samples inventory, presumptive positive B. anthracis culture, rule out smallpox, rash, sample tested positive for Ricin, smallpox vaccine adverse reaction, smallpox vaccine discovered, secondary smallpox vaccine exposure, ulceroglandular tularemia, vaccinia, vaccinia/ Vaccinia Immune Globulin requests, a vaccinia suspect, and an empty cargo container with the word “anthrax” spray painted on it.
 
The 123 observations included in the dataset do not reflect the total number of calls received by CDC or directly to CDC SMEs with bioterrorism-related questions, nor does it reflect all calls received in the CDC EOC or calls received in the EOC and triaged to CDC DPEI/EPRB for issues unrelated to potential bioterrorism threats (e.g., foodborne outbreaks, influenza, natural disasters.) Rather, the 123 observations reflect the calls that were received in the EOC and triaged to CDC DPEI/EPRB which involved an act, threatened act, suspicious lab test, clinical manifestation, or consultation associated with selected biothreat agents. As noted previously, many events were also addressed at the state level or below and were never reported to CDC DPEI/EPRB; our report addressed only those incidents that reached CDC DPEI/ EPRB.
 
Conclusions
 
CDC DPEI/EPRB received nearly 70 requests for assistance with potential bioterrorism-related events in the three year period between January 2007 and December 2009. Among incidents reported to CDC DPEI/EPRB, significant predictors for requesting CDC DPEI/EPRB assistance were type of potential bioterrorism-related incident and the reporting agency. In the logistic regression model, time of notification and season had no significant effects on requests for CDC DPEI/EPRB assistance.
 
Findings from this study could serve as a methodology for state and local health departments to better model the demand on the time of their staff so that they can more efficiently utilize their resources when providing assistance during potential bioterrorism-related incidents or other events of public health significance. Furthermore, this study could have comparable policy implications for other levels of federal, state and local government.
 
Acknowledgments
 
The authors thank Jay Wenger, MD, MPH, Stephen Papagiotas, MPH and Paula Rosenberg, BA for helpful comments and suggestions on the manuscript.
 
 
References