CSTE Overdose Anomaly Toolkit: Introduction


Last Updated: August 2022

Drug overdoses, including those involving opioids, continue to increase in the United States. In the last two decades, the number of drug overdose deaths has quadrupled, rising from 16,849 in 1999 to in excess of 70,000 in 2019, totaling more than 840,000 drug overdose deaths during this time period.1 The majority of these drug overdose deaths involved an opioid, including two-thirds of all drug overdose deaths in 2019.2 Recent increases in drug overdose deaths appear to have accelerated during the COVID-19 pandemic.3 In addition, public health has responded to wide-scale events in recent years in substance using populations, including a 2018 cluster of coagulopathy cases with exposure to rat poison in synthetic cannabinoids 4 and the 2019 e-cigarette or vaping product associated lung injury (EVALI) investigation.5,6 

Plan, Evaluate, Act Graphic

These events and all overdose increases required coordination of public health with partners in first response (EMS, law enforcement and fire) and community harm reduction programs, and treatment providers for effective surveillance and response. 

The definition of an unusual increase, such as an outbreak, or cluster can vary and depends on the circumstances in the local community.  In general, a public health outbreak can be defined as a localized epidemic, where more cases than expected are noted in a specific area or group of people over a particular time period.  

CSTE Overdose Anomaly Toolkit

The CSTE Overdose Anomaly Toolkit (herein referred to as the Toolkit) is designed to provide public health response team with a comprehensive approach to conducting a timely and effective investigation in response to notable increases in overdoses in a city, county, or region. This Toolkit is intended to improve the use of overdose surveillance data and guide public health prevention and response activities in an ever-changing drug environment with increasingly lethal drugs. The Toolkit provides guidance, tools, and techniques featuring real examples of jurisdiction-based activities to epidemiologists and other public health professionals seeking to better prepare for, detect, and respond to drug overdose outbreaks in their communities. The guidance presented in this Toolkit reflects the tools identified and prepared through participation in the CSTE Overdose Spike Alert Advisory Workgroup, whose membership includes CDC, state, and local health department representatives, and CSTE staff members and consultants. This Toolkit addresses overdose from both prescription and illicit substances and could be applied to other public health events as well (such as COVID-19, etc.).  

How to use this Toolkit?

The Toolkit is organized around three activity areas: plan, act, and evaluate.  The activities form an iterative model that can be used to support public health responders during an overdose event.

  • The Plan section provides guidance for understanding the circumstances likely to result in an overdose event in a given jurisdiction.
  • The Act section outlines how to think through actions including considerations for engaging your available data sources and stakeholders, determining appropriate communication strategies and building capacity for future anomalies.
  • The Evaluate section describes the activities and tools used for assessing and improving programs.

The Toolkit and its resource links can be used to support a responder’s efforts to:

  • Gather quantitative and qualitative data to aid in developing a public health response to an overdose outbreak including:  
    • Distributing naloxone  
    • Recognizing the need for multiple doses of naloxone to reverse some overdoses   
    • Developing of public health messaging and recommendations for health professionals, law enforcement, harm reduction partners, and populations at risk 
  • Identify key risk factors for overdoses that can be targeted by prevention activities 
  • Characterize populations experiencing deaths that involve particularly lethal substances (one example being fentanyl) for comparison with populations experiencing heroin-involved and prescription opioid-involved overdose deaths 
  • Support efforts to link people at high risk of overdose to substance use disorder treatment and harm reduction services 
  • Identify strategies for preventing future overdoses 
  • Provide situational awareness for those conducting toxicology testing (including Medical Examiners and Coroners) 
  • Have conversations with the media regarding large-scale events

All resources links in this toolkit were updated and active at the time of release. If you note any broken links or missing files, please bring this to our attention by using the contact us feature.

Why is this Toolkit needed?

Ever-changing trends of drug use and an increases in the prevalence of lethal drugs creates a greater need to for public health response partners and law enforcement. Rapid identification and assessment of overdose anomalies are critical to respond to the drug overdose epidemic, as are efforts to effectively prevent these events from occurring. Response partners include harm reduction, treatment programs, and substance use disorder policy management. The public health response team must have the expertise and tools to quickly answer questions about a potential overdose anomalies and take action to respond. 

This Toolkit includes resources, tools, and investigation steps that can support response team’s efforts to adequately address overdose anomalies.

The Toolkit describes an overdose investigation in a series of steps:

  • Prepare for and detect an overdose anomaly
  • Maintain situational awareness of drug overdose related threats
  • Define and find related cases
  • Generate hypotheses about likely causes using descriptive epidemiology
  • Evaluate hypotheses with additional analyses to identify a source of the anomaly.
  • Institute control and prevention measures
  • Decide when the outbreak or cluster is over and maintain surveillance
  • Communicate findings and conduct an evaluation of the investigation
  • Identify and develop a plan to address lessons learned

Acknowledgement Statement

Acknowledgement Statement: This project was funded through the Centers for Disease Control and Prevention’s National Center for Injury Prevention and Control, Cooperative Agreement Number 1NU1ROT000018-01-03.  Content was developed in collaboration with CSTE Overdose Anomaly Advisory Group, CSTE members, ThoughtBridge, LLC and CDC Subject Matter Expert contributors. Views expressed do not necessarily represent the views of the Centers for Disease Control and Prevention.


  1. Drug Overdose Deaths: Drug Overdose Deaths Remain High. Centers for Disease Control and Prevention. Available at: https://www.cdc.gov/drugoverdose/deaths/index.html
  2. H. Drug Overdose Deaths in the United States, 1999-2017. 8 (2018). 
  3. Centers for Disease Control and Prevention. Increase in Fatal Drug Overdoses Across the United States Driven by Synthetic Opioids Before and During the COVID-19 Pandemic. CDC Health Alert Network Advisory. December 18, 2020. Available at: https://emergency.cdc.gov/han/2020/han00438.asp
  4. Moritz E, Austin C, Wahl M, et al. Notes from the Field: Outbreak of Severe Illness Linked to the Vitamin K Antagonist Brodifacoum and Use of Synthetic Cannabinoids — Illinois, March–April 2018. MMWR Morb Mortal Wkly Rep 2018;67:607–608. DOI: http://dx.doi.org/10.15585/mmwr.mm6721a4
  5. Brian A. King, Ph.D., Christopher M. Jones, Dr.P.H., Grant T. Baldwin, Ph.D., and Peter A. Briss, M.D. The EVALI and Youth Vaping Epidemics – Implications for Public Health. February 20, 2020. N Engl J Med 2020; 382:689-691. DOI: 1056/NEJMp1916171
  6. Krishnasamy VP, Hallowell BD, Ko JY, et al. Update: Characteristics of a Nationwide Outbreak of E-cigarette, or Vaping, Product Use–Associated Lung Injury — United States, August 2019–January 2020. MMWR Morb Mortal Wkly Rep 2020;69:90–94. DOI: 10.15585/mmwr.mm6903e2 

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