Title: Healthcare Preparedness and Response Issues
1Healthcare Preparedness and Response Issues
- Patricia M. Simone, M.D.
- Division of Healthcare Quality Promotion
- Centers for Disease Control and Prevention
2Outline
- Healthcare impact
- Role of healthcare system
- Readiness
- Plans and recommendations
- Division of Healthcare Quality Promotion, CDC
- Key healthcare issues
- Role of NVAC Pandemic Influenza Working Group
3Estimated Burden in the United States
- Based on past pandemics, 15-35 of U.S.
population may become clinically ill with
influenza virus - 18 to 42 million outpatient visits
- 314,000 to 733,000 hospitalizations
- 89,000 to 207,000 deaths
- Meltzer et al. EID 19995659-71.
4Healthcare Impact
- High demand for services
- Estimated gt25 increase in demand for inpatient
beds, ICU beds, and ventilators for a mild
pandemic - Staff absenteeism
- 1957/58 (UK) 20 absenteeism rate 1/3 of staff
in one hospital was ill during peak - Limited availability of critical resources
5FluSurge
- Tool to estimate impact of pandemic on community
- Census data
- Hospital data
- Staffed beds, staffed ICU beds, ventilators
- Estimates
- Numbers of hospitalizations and deaths
- Number of beds (ICU and non-ICU) and ventilator
capacity needed - Based on
- Duration of pandemic (weeks)
- Gross clinical attack rate (15, 25, or 35)
www.cdc.gov/flu/flusurge.htm
6Estimates Using FluSurge Software
- Example impact of an 8-week influenza pandemic
with 25 gross clinical attack rate - Demand of hospital resources peaked in week 5
- 27 of all hospital beds
- 54 of total ICU capacity
- 29 of all ventilators
- Total burden
- 9,707 hospital admission (ranging from 3,310 to
12,924) - 1,741 deaths (ranging from 782 to 3,120)
7Pandemic Response Components
Pandemic influenza disease
Interventions to prevent disease transmission
Provide quality medical care
Infection control in healthcare settings
Impact
Maintain essential services/ response activities
Antiviral treatment prophylaxis
Vaccination
Time
8Role of Healthcare System in Pandemic Response
- Provide quality care
- Adequate staffing
- Adequate equipment and supplies
- Prevent transmission to patients and HCWs
- Triage and early detection
- Implementation of infection control measures
- Coordinate with other healthcare settings and
health department
9Assessment of Hospital Preparedness for Emerging
Infectious Disease Threats
- 556 hospitals in 47 states and Puerto Rico
completed a survey on hospital preparedness - Many hospitals had SARS plans but few had
coordinated them with other facilities or
jurisdictions - Infection control and certain specialty services
were limited in small and rural hospitals - The number of negative pressure rooms and other
medical equipment/supplies may not be adequate
for a large event
10Proportion of Hospitals Lacking Infection
Control Workforce by Bedsize
Bed size lt100 100-299 300-499 500 N
224 N-142 N154 N32 Infection Control 44
(20) 7 (5) 3 (2) 0 Practitioner Hospi
tal 215 (96) 114 (80) 109 (71) 11
(34) Epidemiologist ID Physician 186 (83) 79
(56) 45 (29) 0 Occupational Health 180 (80)
91 (64) 83 (54) 6 (19) Physician Occupational
Health 110 (49) 37 (26) 9 (6) 1
(3) Nurse
11US Hospitals by Bed Size
Source AHA Annual Survey 2002
12Results of APIC Influenza Survey2003/2004 Season
- Shortages
- Diagnostic kits (50)
- Staffing (35)
- Vaccine (25)
- Beds (28)
- Diversions averaging 6 days in 9 of facilities
- HCW vaccination rate of 50
- Respiratory hygiene program consistent with
CDC/HICPAC recommendations implemented in 81
13Field Exercises - Observations
- Lack of adherence to proper infection control
practices and confusion about PPE use - Inadequate planning for
- exposure management of healthcare workers
- surge capacity including staff, beds, equipment,
and laboratory services - Inadequate healthcare staff with appropriate
expertise during non-peak hours - Unclear notification and communication channels
internally and externally
14Participants
- WHO
- HHS (CDC, HRSA)
- State and local health departments
- Hospitals
- Emergency responders
- Professional organizations
- Providers
15WHO Plan New Phases
- Interpandemic
- Phase 1 no new subtypes in humans subtype in
animals with low risk of human infection - Phase 2 no new subtypes in humans subtype in
animals with substantial risk of human disease - Pandemic alert
- Phase 3 human infections with new subtype no
or rare human-to-human spread - Phase 4 small clusters of human-to-human
transmission - Phase 5 large clusters of human-to-human, but
localized - Pandemic period
- Phase 6 sustained transmission
- Postpandemic period
www.who.int/csr/disease/influenza/inforesources/en
/
16HHS Plan Healthcare and Emergency Response
- Inter-Pandemic Phase (Phase 0, level 1 and 2)
- Assess capacity of healthcare and emergency
response system to meet needs in a pandemic
(ASPHEP) - Inter-Pandemic Phase (Phase 0, level 3)
- Review and revise plans for healthcare delivery
and community support (HHS, HRSA) - Assess availability of personnel, supplies and
materials for infection control and clinical care
of infected patients should a pandemic occur
(HRSA) - Disseminate infection control guidelines to
hospitals, long-term care facilities, and medical
care providers (HRSA, CDC)
17HHS Plan Healthcare and Emergency Response
- Pandemic confirmed (Phase 1)
- Activate state and local plans to coordinate
healthcare delivery and community response
(ASPHEP, HRSA) - Pandemic spreading (Phase 2)
- Establish inpatient medical care in
non-traditional facilities to provide hospital
bed surge capacity (HRSA) - Assess quality of healthcare and emergency
response (HRSA) - End of first wave (Phase 3)
- Assess effectiveness of healthcare and service
delivery during prior phases and revise as needed
(ASPHEP)
18HRSA Cooperative AgreementCritical Benchmarks
- Must be achieved by August 31, 2007
- Establish a system for triage, treatment, and
initial stabilization of 500 adult and pediatric
patients per 1,000,000 above current capacity - Ensure all participating hospitals can maintain
at least one case of a highly infectious disease
in negative pressure isolation and have at least
on regional facility that can support the initial
evaluation and treatment of at least 10 patients
at a time in negative pressure isolation
19HRSA Cooperative AgreementCritical Benchmarks
- Establish as system for immediate deployment of
additional HCWs in support of surge bed capacity - Develop a system for advance registration and
credentialing of clinicians needed for surge
capacity - Establish regional plans to insure supply of
prophylaxis meds for 3 days (HCWs and community) - Ensure adequate PPE for surge capacity staff
- Ensure adequate decontamination systems
- Enhance capacity of care related to behavioral
health consequences
20HRSA Cooperative AgreementCritical Benchmarks
- Cross-cutting benchmark Preparedness for
Pandemic Influenza - Describe current plan for response
- Provide a complete plan (summer 2005)
21CDC Division of Healthcare Quality Promotion
- Infection control guidance (HICPAC)
- Evaluation of prevention measures
- Investigation of healthcare-associated outbreaks
- Established networks with hospitals
- Long-standing partnerships (APIC, SHEA, AHA)
- Monitoring adverse events (antivirals with FDA)
- Healthcare and Infection Control supplement for
CDC plan
22CDC Plan
- Preparedness Planning for Hospitals
- Disease surveillance
- Hospital communications
- Education and training
- Triage and admissions
- Facility access
- Occupational health
- Vaccine and antiviral use and adminstration
- Surge capacity
- Mortuary issues
23CDC Plan
- Preparedness planning for non-hospital settings
- Infection control recommendations for hospitals
and non-hospital settings - Infection Control Supplement
- Hospital Preparedness Checklist
- Tabletop exercises
24(No Transcript)
25Issues
- Coordination
- Surge capacity
- Alternative care sites
- Planning and implementation tools
- Mask and respirator recommendations
- Preparing the public (expectations)
- Monitoring progress
26Coordination
- How to facilitate coordination of planning
efforts? (consistency of recommendations and
efficient use of resources) - At national, state, and local levels?
- Between public health and healthcare systems?
- Among healthcare systems?
- With other planning activities? (SARS)
- What else needs to be done?
- How can it be implemented?
27Surge Capacity
- What is the true capacity for increasing the
number of available HCWs? (e.g., available number
of administrators with clinical competence,
volunteers) - What are the barriers using volunteers? How can
they be addressed? - Should the focus be on efficient use of current
resources?
28Alternative Care Sites
- What federal sites are available nationwide?
- How well are states doing in assessing
availability of other sites? - What tools are available for assessing
requirements?
29Tools
- What tools are available to assist healthcare
facilities and health departments in planning and
implementation? - Use existing tools (e.g., FluSurge, guideines)
- Identify other tools that can be adapted
- Which ones are priority for development?
30Examples of Tools
- Tracking systems (staffing, beds, flow of care,
supplies, etc.) - Triage algorithms
- Hotline templates
- System for detecting transmission in the hospital
- Public education tools
- Templates for daily reports and other
communication tools - Emergency training materials for volunteers
- Protocols to prioritize procedures, limit
elective admissions - Staffing priority groups
- Consumable resource needs
- Vaccine and antiviral distribution models
- Description of field hospital requirements
31WHO Plan Measures to Reduce Risk of Transmission
- Confinement
- plan for large numbers
- type not specified
- Face masks
- Symptomatic persons surgical mask
- Exposed persons
- Consider use and type based on risk assessment
- N95 for HCWs
- Public places permitted but not encouraged
32Respirators and Masks
- Influenza recommendations
- Standard and droplet precautions
- Surgical mask for HCWs
- Private room
- Avian influenza recommendations
- Airborne isolation
- N95 for healthcare workers
- Airborne isolation room (negative pressure)
- Pandemic influenza
- WHO plan implies N95 for HCWs
- Graded response? (maximum precautions early for
containment but not feasible later) - Use in public places (permit but not encourage?)
33Preparing the Public
- How do we best prepare the public?
- Stay home when sick
- Respiratory hygiene and cough etiquette
- Telephone triage
34Monitoring Progress
- How to prioritize preparedness activities
(limited resources)? - How to monitor progress toward readiness?
- Benchmarks
- Timelines
- Testing
- Coordination
35NVAC Pandemic Preparedness Work Group
- Facilitate coordination
- Review and provide input on guidance
- Unresolved issues
- Surge capacity
- Alternative care sites
- Assess barriers to implementation
- Identify existing tools and other resources
- Prioritize needs
- Monitor progress
36(No Transcript)
37Healthcare Preparedness for Pandemic
- Impact of previous pandemics
- Inter-pandemic preparedness planning
- Surveillance
- Capacity and supplies
- Communication and Education
- Lessons learned from SARS
38 Timeline of Emergence of Influenza Viruses
in Humans
Avian Influenza
H7
H9
Pandemic vaccines
H5
H5
B
Russian Influenza
H1
Asian Influenza
Regular vaccines
H3
Spanish Influenza
H2
Hong Kong Influenza
H1
1998/9
1918
1957
1968
1977
1997
2003
39Pandemic Spread
- Spread of pandemic
- Months to reach U.S. of prior pandemic strains
1918- 0 1957 2-3 1968 2-3 1977 3-4 - International travel---Globalization
40Impact of Previous Pandemics
- Spanish flu 1918-19 killed 20-40 million people,
675,000 in the United States. - Asian flu (57-58) and Hong Kong flu (68-69)
killed a total of 103,600 people in the United
States. - Annual influenza epidemics cause 36,000 deaths
and 226,000 hospitalizations in the United
States.
41Previous Pandemics
- Besides the elderly, excess of mortality is also
likely in younger adults and children - 1918/19 higher mortality in younger adults and
children - 1957 higher mortality in older adults
- 1968/69 higher mortality in children and older
adults - In planning, consider several scenarios based on
clinical attack rates, case fatality rate etc.
42Estimated Number of Cases by Outcome, Attack
Rate of 15, Canada
Source Canadian Pandemic Influenza Plan
43Healthcare Preparedness for Pandemic
- Impact of previous pandemics
- Inter-pandemic preparedness planning
- Surveillance
- Capacity and supplies
- Communication and Education
- Lessons learned from SARS
44Inter-Pandemic Preparedness for Hospitals
- Objective develop planning and decision-making
structures for responding effectively to pandemic
influenza - Create and test a plan that provides efficient
and effective healthcare to influenza-infected
patients and minimizes the disruption of other
healthcare delivery - Build partnerships with state and local health
departments, local and/or regional healthcare
facilities
45Inter-Pandemic Planning
- Facilitate awareness of the potential impact of a
pandemic on the healthcare system - Prepare resources and guidelines that may be
adapted during pandemic (clinicians, patients,
and family members) - Educate and train healthcare personnel to detect
patients with influenza, support surveillance
systems, and manage and treat patients
46Disease Surveillance
- Establish a system to detect cases and relay
information to local and/or state health
departments - Surveillance for ILI in ER and outpatient
settings - System for internal review of pandemic influenza
activity in patients to the emergency department - Laboratory surveillance for unusual isolates
- System to detect transmission in the institution
- Test plan using non-pandemic influenza as a
surrogate agent -
47Assess Your Capacity
- Assess bed and ventilator capacity
- Assess supply needs for consumable resources
(e.g., PPE) - Assess morgue capacity
- Prepare for airborne isolation
- Mobilize required resources (e.g., medical,
emergency response) within respective jurisdiction
48Prioritize Beds
- Spectrum of illness is broad, ranging from
asymptomatic infections to death -- Be prepared
for complications - Develop criteria and plans for limiting access to
the healthcare facility during a pandemic - Prioritize elective medical and surgical
admissions - Develop policies and procedures for expediting
discharge of patients who do not require
inpatient care
49Community Coordination
- Coordinate and develop agreements with other
facilities in the community/ region - Health departments
- Home health care
- Long term care
- Primary care
50Emergency Services and Triage
- Emergency services
- Encourage collaboration between emergency service
personnel and public health authorities - Facilitate continuous state of readiness through
ongoing educations, testing, revision of plans - Triage and clinical evaluation of patients
- Develop and test options for triage during peak
of pandemic
51Respiratory Hygiene/Cough Etiquette
- Universal strategy for patients with symptoms of
respiratory infection at initial point of contact
with healthcare system - Visual alerts
- Tissues or surgical masks for patients
- Hand hygiene materials in waiting areas
- Physical separation of patients with febrile
respiratory illnesses - Masks for healthcare workers caring for febrile
respiratory patients and use Droplet precautions
52Staffing Issues
- Plan on what to do when the healthcare system is
overwhelmed and care must be provided by persons
doing work which is normally not part of their
daily activities - Develop strategies to meet the range of staffing
needs (e.g., recruit retired healthcare
personnel) - Engage clinicians in flu-related activities
(e.g., provide data from ILI surveillance) - Psychological support to healthcare workers
53Education
- Clinicians and other healthcare professionals
- diagnosis and treatment
- prevention of transmission
- Patients and family members
- respiratory hygiene
- when to go to the hospital
54Communication Plan
- Establish rapid and ongoing communication with
- public health officials
- other healthcare facilities,
- lay public and press
- public officials
- Ensure that a system is in place for timely
communication about pandemic influenza within the
healthcare facility - Develop and test a plan to communicate/educate
patients and visitors to avoid the hospital
55Vaccination and Antiviral Use
- Plan to use (and distribute) antiviral agents for
prophylaxis and treatment - Healthcare personnel
- Patients and family members
- Plan to prioritize the use of vaccines
- Develop a system to monitor
- Work with local and state health department
- Promote vaccination during inter-pandemic period
56Test the System
57Healthcare Preparedness for Pandemic
- Impact of previous pandemics
- Inter-pandemic preparedness planning
- Surveillance
- Capacity and supplies
- Communication and Education
- Lessons learned from SARS
58Lessons from SARS
- Early detection is vital
- Healthcare personnel resources can be affected by
illness, fatigue, and fear - Infection control also requires attention to
visitors and family members - Education and training with regular updates are
necessary - Clear chains of decision making and communication
are needed
59Assessment of Hospital Preparedness for Emerging
Infectious Disease Threats
- 556 hospitals in 47 states and Puerto Rico
completed a survey on hospital preparedness - Many hospitals have SARS plans but few have
coordinated them with other facilities or
jurisdictions - Infection control and certain specialty services
are limited in small and rural hospitals - The number of negative pressure rooms and other
medical equipment/supplies may not be adequate
for a large event
60Proportion of Hospitals Lacking Infection
Control Workforce by Bedsize
Bed size lt100 100-299 300-499 500 N
224 N-142 N154 N32 Infection Control 44
(20) 7 (5) 3 (2) 0 Practitioner Hospi
tal 215 (96) 114 (80) 109 (71) 11
(34) Epidemiologist ID Physician 186 (83) 79
(56) 45 (29) 0 Occupational Health 180 (80)
91 (64) 83 (54) 6 (19) Physician Occupational
Health 110 (49) 37 (26) 9 (6) 1
(3) Nurse
61US Hospitals by Bed Size
Source AHA Annual Survey 2002
62Smallpox and SARS Field Exercises
- Purpose to identify operational, logistical,
communication, and administrative needs to
prepare and manage BT or epidemic events - Participants
- Airlines
- Local law enforcement, EMS, emergency planners
- Local and state public health departments
- Local healthcare facilities
- Custom and Border Patrol, Port Authority, TSA,
DHS, and CDC
63Field Exercises - Observations
- Lack of adherence to proper infection control
practices and confusion about PPE use - Inadequate planning for
- exposure management of healthcare workers
- surge capacity including staff, beds, equipment,
and laboratory services - Inadequate healthcare staff with appropriate
expertise during non-peak hours - Unclear notification and communication channels
internally and externally
64Conclusion
- Several actions can be taken to better prepare
for pandemic influenza - We need to use lessons learned from SARS response
and examples from previous pandemics to improve
preparedness for pandemic influenza - Test the system individual and regional will
help to identify gaps that can be addressed in
the inter-pandemic period
65Hurry Up and Get Ready!!!
66PREVENTION IS PRIMARY!
Protect patientsprotect healthcare
personnel promote quality healthcare! Division
of Healthcare Quality Promotion
67Distribution of Respondents, Hospital Preparedness
Assessment, N556
31 21-30 11-20 1-10 0
68Healthcare Planning and Preparedness Needs
- Surge capacity staff, beds, supplies, equipment
- Regional coordination/collaboration
- Triage
- Infection control
- Delivery of interventions to staff and patients
69Marburg Virus Hemorrhagic Fever
- Angola, October 2004- April 5th, 2005
- Total of 163 cases, 150 fatal
- 75 of reported cases in children aged lt5 years
- Healthcare workers
- Predominant symptoms fever, hemorrhage,
maculopapular rash, vomiting, cough, diarrhea,
and jaundice -
70Act Now!Address Prevention Planning Priorities
in Emergency Departments, Outpatient Offices, and
Inpatient Units
71Pandemic Period New Virus Transmitted
Person-to-Person Abroad
- Objective Heighten institutional surveillance
for influenza and prepare to activate
institutional pandemic influenza plans - Collaborate with key partners on planning
preparations - Heighten surveillance
- Reinforce basic infection control measures to
prevent spread of influenza - Accelerate training
72Pandemic Period Virus Transmitted
Person-to-Person in United States
- Objective Maintain integrity of healthcare
delivery services while responding to the
communitys need for quality care - Rapidly identify, isolate, and treat all patients
with potential pandemic influenza - Continue to provide healthcare by implementing
system to increase capacities - Maintain rapid and frequent communication within
and among healthcare facilities and with state
and local health departments to optimize response
and control efforts.
73Influenza vs. SARS
74Lessons Learned
- Communication
- Compliance with basic infection control
- Leadership support
- Clinicians engagement
- Collaboration with community and public health
planning groups - Globalization
75Surveillance Plan during pandemic
- Monitor morbidity and mortality associated with
pandemic - Determining if transmission is occurring in the
facility potential breaches of infection
control
76Infection control is EVERYONEs responsibility!
77Lessons Learned from SARS (1)
- Transmission risks are primarily from
- Unprotected exposures to unrecognized cases in
both inpatient and outpatient settings. - We must look beyond the patient contacts may be
infectious too. - Prevention begins when a patient or visitor walks
through the door of an Emergency Department or
outpatient office.
78Lessons Learned form SARS (2)
- Use of PPE prevents transmissionhowever,
- Healthcare personnel need instruction on how to
don, use and remove PPE - Wearing PPE for extended periods of time is a
burden and can lead to breaches in technique
79Education and Training Plan
- Clinical personnel should be educated about
influenza disease, diagnosis and management - Highlight the importance of vaccination
- Educate all facility and patients, family members
and visitors about the prevention and control - Triage and clinical evaluation of patients
-
80When in North America?
- Canada within 3 months after it emerges in
another part of the world - Spreads in 2 or more waves 3-9 months of
initial outbreak
81Is a Pandemic Imminent?
- New influenza A virus arising from a major
genetic change - Susceptible population with little or no immunity
- Virus transmitted efficiently from
person-to-person - Virulent virus with capacity to cause serious
illness and death
82Factors Increasing Concern
- H5N1 has infected mammals (humans, cats, and
pigs) - The influenza season (H3N2) in northern Vietnam
is ongoing concurrent with avian influenza - Endemic H5N1 in ducks and wild birds makes
eradication of this strain unlikely - Antigenic change continues to occur
83Assessment of Hospital Preparedness for Emerging
Infectious Disease Threats
- GAO survey suggested urban hospitals are ill
prepared for a major biologic event - SARS pandemic highlighted
- Importance of infection control programs and
workforce - Need for adequate equipment and supplies
84Preparedness Planning Healthcare
- Preparedness Plan Elements
- Organizational infrastructure
- Logistics of patient care
- Staffing
- Durable and consumable resources
- Exposure management
- Patient focused pre-event planning
- Fix the weaknesses in the system
85Creating the Organizational Infrastructure
- Multi-disciplinary team
- Scientific leadership healthcare
epidemiology/infection control - Administrative leadership
- Clinical representation
- Engineering/Environmental Services
- Communications/public relations
- Safety/security
- Other
86Respiratory Hygiene/Cough Etiquette
- Universal strategy for patients with symptoms of
respiratory infection at initial point of contact
with healthcare system - Visual alerts
- Tissues or surgical masks for patients
- Hand hygiene materials in waiting areas
- Physical separation of patients with febrile
respiratory illnesses - Masks for healthcare workers caring for febrile
respiratory patients and use Droplet precautions
87APIC Influenza Survey
- Assess the impact of the 2003/2004 influenza
season on healthcare facility resources - Assess adoption of respiratory hygiene programs
88Availability of Preparedness Plans
- N ()
- Written SARS plan 320 (58)
- Coordination of plan with
- local heath department 247 (77)
- healthcare facilities 175 (55)
- municipalities 85 (27)
89Workforce Resources
Total Urban Rural p-value () () () Microbiol
ogist 65 78 41 lt.0001 Pulmonologist 65 84 30 lt.00
01 Mental Health 61 71 42 lt.0001 Counselor Healt
h Communicator 77 87 60 lt.0001 Bioterrorism 76 77
72 .1 Coordinator
90Proportion of Hospitals Lacking Infection Control
Workforce by Bedsize
Bed size lt100 100-299 300-499 500 N
224 N-142 N154 N32 Infection Control 44
(20) 7 (5) 3 (2) 0 Practitioner Hospi
tal 215 (96) 114 (80) 109 (71) 11
(34) Epidemiologist ID Physician 186 (83) 79
(56) 45 (29) 0 Occupational Health 180 (80)
91 (64) 83 (54) 6 (19) Physician Occupational
Health 110 (49) 37 (26) 9 (6) 1
(3) Nurse
91Equipment Resources
Total Urban Rural p-value () () () 1
NPR on wards 86 92 75 lt.0001 1 NPR in
ICU 64 79 38 lt.0001 1 NPR in ER 57 72 33
lt.0001 ability to create NPR 34 37 28 .03 1
mechanical ventilator 91 95 84 .0003 1
portable HEPA filter 51 55 45 .02 1 portable
x-ray machine 97 98 98 .5 NPR negative
pressure room
92Workforce Resources
Occupation None Median FTE Range Infection
Control 12 1 0 - 10 Practitioner Hospital 81
0.0 0 5 Epidemiologist ID Physician 56 0.0
0 17 Occupational Health 65 0.0 0
5 Physician Occupational Health 29 1 0
15 Nurse
93Other Healthcare Settings
- Criteria for readmission
- Of one case, assume all are exposed
- Cancel or postpone procedures
- Coughing residents stay in their rooms
94Smallpox and SARS Field Exercises
- Purpose to identify operational, logistical,
communication, and administrative needs to
prepare and manage BT or epidemic events - Participants
- Airlines
- Local law enforcement, EMS, emergency planners
- Local and state public health departments
- Local healthcare facilities
- Custom and Border Patrol, Port Authority, TSA,
DHS, and CDC