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June
2007: VOLUME
1, NUMBER 8
We
are proud to announce that Jonathan M. Zenilman, MD, Chief, Infectious
Diseases Division at The Johns Hopkins Bayview Medical Center has joined
as Co-Program Director.
In this issue...
Community
Strategy for Epidemic Influenza Mitigation in the United States
As long as the possibility of
an influenza pandemic exists, the need for a comprehensive and coordinated
mitigation plan remains a priority. In February 2007, the CDC issued
a planning guidance document addressing the issues surrounding community
mitigation. Designed as a first iteration, to be revised as knowledge
gained from continuing research becomes available, a primary focus of
the document is on non-pharmaceutical interventions (NPIs).
In this issue, in a departure
from our usual format, we highlight the CDC’s key recommendations for
supplementing what can be achieved with medications in the event of
pandemic influenza. |
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Program
Directors
John
G. Barlett, MD
Professor of Medicine
Department of Medicine
The Johns Hopkins
University
School of Medicine
Jonathan
M. Zenilman, MD
Professor of Medicine
Chief, Infectious
Diseases Division
The Johns Hopkins
University
School of Medicine
Jason
E. Farley, PhD(c), MPH, NP
Adult Nurse Practitioner,
Infectious Disease
Clinical Instructor,
Department of Medicine
The Johns Hopkins
University
School of Medicine |
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GUEST
AUTHOR OF THE MONTH |
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Commentary
& Reviews: |
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John
G. Barlett, MD
Professor
of Medicine
Department
of Medicine
The Johns
Hopkins University
School
of Medicine |
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Guest
Faculty Disclosure
John
G. Bartlett, MD, has disclosed that he has served on the HIV
Advisory Board for GlaxoSmithKline, Abbott and Bristol-Myers Squibb.
Unlabeled /Unapproved Uses
The authors have indicated that there will be no reference
to unlabeled/ unapproved uses of drugs or products in this presentation.
Course
Directors' Disclosures |
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the conclusion of this activity, participants should be able to: |
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Describe
the CDC recommendations for mitigating person-to-person transmission
of pandemic influenza |
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Explain
the criteria proposed to implement the proposed strategies |
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Discuss
the additional research required to develop these initial recommendations |
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COMPLETE
THE POST TEST
Step 1.
Click on the appropriate link
below. This will take you to the post-test.
Step 2.
If you have participated in a
Johns Hopkins on-line course, login. Otherwise, please register.
Step 3.
Complete the post-test and course
evaluation.
Step 4.
Print out your certificate.
Pharmacy credit is only available via PDF mail-in form:
 |
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The
primary strategies for combating influenza are: 1) vaccination,
2) treatment of infected and exposed individuals with antiviral
medications, and 3) implementation of infection control and social
distancing measures. Although the single most effective intervention
will be vaccination, it is highly unlikely that a well-matched vaccine
will be available when a pandemic begins – and current vaccine technology
would require a probable 4 to 6 months after the start of a pandemic
to make such a vaccine available. In addition, it is likely that
the amounts of vaccine produced will not be adequate to cover the
entire population. Further, it is unknown whether sufficient quantities
of antiviral medications will be available, as well as whether a
vaccine will be effective in-vivo even if it is active in-vitro.
Therefore, in preparation
for a pandemic situation without sufficient quantities of vaccine
and antivirals, the CDC issued Interim Pre-pandemic Planning
Guidance: Community Strategy for Pandemic Influenza Mitigation in
the United States in February 2007 (www.pandemicflu.gov/plan/community/mitigation.html).
Most of the guidelines presented are based on the concept of "social
distancing." Among the assumptions the authors make are that person-person
contact is the major method of transmission of influenza; viral shedding
begins about one day before the onset of symptoms and reaches a zenith
during the first few days of the infection; and that children have
the highest titers of virus, the most prolonged periods of shedding,
and are the major vectors of disease. The recommendations provided
are based in part on "Models of Infectious Disease Agent Studies,"
which are computer
simulations of influenza outbreaks funded by the NIH1-3,
as well as historical data drawn from experiences recorded during
the 1918 pandemic4. It should be noted that in the latter,
when comparing cities that did extensive influenza planning (such
as St. Louis) versus those that did not (such as Philadelphia), strategies
based on social distancing showed a significant public health benefit.
The conclusion by the CDC is that the experience in 1918 and the
computer modeling studies show "strands of evidence" that indicate
the currently proposed methods would benefit public health by limiting
or slowing community influenza transmission, with the ultimate effect
of reduced mortality and a broadened epidemic curve – thus lessening
the intensity of a pandemic’s impact on both the healthcare system
and society in general.
It should be emphasized
at the onset that while many of the interventions proposed may provide
these potential benefits, their implementation is complicated by
substantial concerns about societal impact, which is categorized
as the "second and third order consequences." For example, closing
schools requires home care for children, which may prevent parents
from working (and subsequent loss of income), which may lead to reduced
community-based services including healthcare services, the supply
chain, food delivery, etc5. This is simply one example
of the cascading effects of the interventions proposed. |
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SPECIFIC
STRATEGIES PROPOSED |
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The
pandemic mitigation interventions described in the document include:
- Isolation
of cases: Infected patients who do not require hospitalization
should be isolated and treated at home.
- Voluntary
home quarantine of household members: Household members
with confirmed or probable influenza should stay at home, where they
would receive treatment that would include antiviral agents (if there
is a sufficient supply and the drug is active against the pandemic
strain). Other household contacts would also be included, in part
because these are the persons at highest risk of both infection and
of transmitting the disease. Requirements for success include prompt
recognition of illness, appropriate use of hygiene and infection
control practices in the home setting; measures to promote voluntary
compliance; commitment of employers to support the recommendation
that ill employees stay home; and support for the financial, social,
physical, and mental health needs of patients and caregivers. In
addition, special consideration should be made for persons who live
alone, as many of these individuals may be unable to care for themselves
if ill.
- Closure
of schools: Childcare facilities and schools represent an
important point of epidemic amplification, while children themselves
are thought to be efficient transmitters of disease in any setting.
Therefore, both to protect children and to decrease introduction
of the virus into households and the community at large, the CDC
plan calls for closing public and private schools, day care centers,
and colleges and universities. The closure recommendation is based
on the assumption that for social distancing to be effective, it
needs to be further implemented in concert with closure of areas
of "community mixing": thus, malls, theaters, and other gathering
sites where students might congregate would need to be included in
the plans for control. In the event of a full-scale pandemic, schools
may be closed for up to 12 weeks.
- Closure
of businesses and cancellation of public gatherings: The
goals of workplace social distancing measures are not only to reduce
transmission within the workplace and thus into the community at
large and ensure a safe working environment, but also to maintain
business continuity, especially for critical infrastructure. Workplace
measures such as encouragement of alternatives to in-person meetings
("telework"), as well as modifications to work schedules (such as
staggered shifts) may be important in reducing social contacts and
the accompanying increased risk of transmission. The success of these
measures are dependent on the commitment of employers to provide
options and make changes in work environments to reduce contacts
while maintaining operations.
Within the community,
cancellation or postponement of large gatherings, such as concerts
or theatre showings may reduce transmission risk. Modifications to
mass transit policies to decrease passenger density may reduce transmission
risk, but such changes will likely create challenging second and third
order consequences. It is noted, for example, that 4.5 million people
use the NYC subway system daily. Closure might make it impossible
to provide vital services including healthcare.
- Infection
control measures: Included in the plan is public education
regarding methods to prevent transmission, such as cough etiquette,
hand hygiene and the use of surgical masks or N95 respirators.
While the CDC document contains
in-depth guidance on how these recommendations can be implemented, providing
the step-by-step details for each NPI is beyond the scope of this eLiterature
Review. Further, as the ultimate responsibility for public health intervention
in the US is state-based, these proposed recommendations need to be
reviewed and endorsed or rejected by state and local health departments. |
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WHEN
WOULD THESE STRATEGIES BE IMPLEMENTED? |
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Implementing
these measures prior to the pandemic may result in economic
and social hardship without public health benefit, as well as, over
time, "intervention fatigue" and an erosion of public adherence. Conversely,
implementing these interventions after extensive spread of
pandemic influenza in a community may limit the public health benefits.
This guidance suggests that the primary activation trigger for initiating
interventions be a laboratory-confirmed cluster of infection, with
a novel influenza virus, and evidence of community transmission (ie,
epidemiologically-linked cases from more than one hospital).
There are 3 important variables
that dictate the intervention and the specific strategy:
1. The first is the severity
of the influenza strain based on case-fatality rates. This CDC guidance
document introduces a Pandemic Severity Index (PSI), which uses case
fatality ratio as the critical driver for categorizing the severity
of a pandemic. The index is designed to enable estimation of the severity
of a pandemic on a population level, allowing public health officials
to better forecast the impact of a pandemic and match mitigation interventions
to the predicted severity. Future pandemics will be assigned to 1 of
5 discrete categories of increasing severity (Category 1 to Category
5), as summarized below:
For reference it should be noted
that the mortality associated with seasonal influenza in the US is less
than 0.1%, and that the highest mortality experienced in an influenza
epidemic was the 1918 pandemic, with a case-fatality rate of 2.4%. It
is therefore sobering to realize that the case-fatality rate for Avian
influenza (which is now sporadic) is about 60%.
2. The second variable is determining
which of the interventions described above should be instituted. These
are based on the PSI level, and are summarized below:
SOURCE: www2a.cdc.gov/phlp/docs/community_mitigation.pdf
3. The third variable is the
WHO (World Health Organization) phase for pandemic flu. WHO has defined
6 phases, occurring before and during a pandemic, which are linked to
the characteristics of a new influenza virus and its spread through
the population. Summarizing the WHO phases:
Source: www2a.cdc.gov/phlp/docs/community_mitigation.pdf
Note that the mitigation strategies
suggested in this CDC document are designed to provide specific pre-pandemic
planning guidance for the use of non-pharmacological interventions only
in the advent of WHO Phase 6. We are currently (June 2007) experiencing
Phase 3. While the WHO phases provide succinct statements about the
global risk for a pandemic and provide benchmarks against which to measure
global response capabilities, the US Government’s approach to pandemic
response characterizes the stages of an outbreak in terms of the immediate
and specific threat a pandemic virus poses to the US population. The
following stages provide a framework for Federal Government actions:
SOURCE: www2a.cdc.gov/phlp/docs/community_mitigation.pdf
Using the Federal Government’s approach, this CDC document provides
pre-pandemic planning guidance from Stages 3 through 5 for step-by-step
escalation of activity, from pre-implementation preparedness, through
active preparation for initiation of the recommendations, to actual
use. |
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The
CDC report acknowledges that a comprehensive research agenda for pandemic
influenza is needed to improve the evidence base of the proposed interventions
described in the current interim guidance. The agency calls for conducting
studies to gain more knowledge about: the epidemiology of influenza,
the effectiveness of community-based interventions, the use of medical
countermeasures that complement community interventions, the modification
of existing mathematical modeling to include adverse societal consequences,
and the development of new modeling frameworks to assess the effectiveness
of interventions. Additional key areas where research is needed include:
- Enhancing
epidemiologic and laboratory surveillance systems for influenza: Existing
influenza surveillance systems have gaps in timeliness and completeness
that will hamper adequate functioning during a pandemic; therefore,
a high priority must be given to the development of more timely surveillance
for laboratory-confirmed cases of human infections, methods to rapidly
estimate the excess mortality rate during a pandemic, and the development
of platforms that can be used to assess the effectiveness of pandemic
interventions.
- Development
of rapid diagnostics: Laboratory diagnosis of influenza
is critical for the treatment, prophylaxis, surveillance, vaccine
development, and timing of the initiation of pandemic mitigation
strategies. The development of sensitive and specific point-of-care
rapid tests for influenza A subtypes with pandemic potential will
play a critical role in pandemic preparedness.
- Measurement
of effectiveness of personal protective equipment (PPE, eg, surgical
masks and respirators) in community settings: Quantification
of the effectiveness of PPE for infection prevention, training community
members to correctly use PPE, the utility of PPE for children and
the elderly for whom PPE is not currently designed, and the relative
contribution of PPE to safety in the context of other interventions
should be undertaken. The main issue here is to develop a thorough
understanding of the relative merits of the surgical mask and the
N95 respirator.
- Determination
of the trigger points for implementation of interventions: While
the historic data from 1918 on the use of non-pharmacological interventions
indicate an ecological relationship between timing and effectiveness,
additional prospective data on timing of each of these measures will
usefully complement the value of historic evidence.
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Planning
and preparedness for implementing pandemic mitigation strategies is
complex and requires participation and specific actions by all levels
of government and all segments of society, including individuals, families,
schools, businesses, and community organizations. It should be emphasized
that the responsibility for public health in the US is state-based,
requiring all states to develop individual plans; however, many have
acknowledged that they do not have the expertise to make decisions
about closing schools and businesses, and have looked to the federal
government for guidance. This CDC document is the initial step in providing
that guidance.
The Pandemic Severity Index,
in which case fatality ratio serves as the critical driver for categorizing
the severity of a pandemic, is designed to enable better forecasting
of the impact of a pandemic, providing a basis for selecting the most
appropriate interventions and balancing the potential benefits against
the expected costs and risks.
While the "social distancing" interventions advocated (school and business
closure, etc) may seem severe, there is evidence from mathematical models
and retrospective analyses from the 1918 pandemic that cities which
implemented community mitigation were successful in reducing mortality
and were more adequately prepared for the surge in demand for hospital
beds and medical personnel. The greatest challenge is the trade-off:
keeping people home sounds relatively simple, but it can be terribly
disruptive, especially if the duration is the anticipated 8-12 weeks.
Note, however, that the recommended plan is meant to be implemented
only if we are in Phase 6 of the WHO classification, which means there
is increased and sustained transmission in the general population at
some place in the world.
As stated above, it is not within
the scope of this eLiterature Review to fully detail the thinking behind,
and the complete recommendations of, the CDC’s Interim Pre-pandemic
Planning Guidance: Community Strategy for Pandemic Influenza Mitigation
in the United States. Clinicians may view the entire document from the
CDC website or by downloading
this PDF.
References
| 1. |
Wu
JT, Riley S, Fraser C, Leung GM. Reducing
the impact of the next influenza pandemic using household-based
public health interventions. PloS Med 2006;3(9):e361. |
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| 2. |
Germann
TC, Kadau K, Longini IM, Macken CA. Mitigation
strategies for pandemic influenza in the United States. Proc
Natl Acad Sci U S A 2006;103:5935-5940. |
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| 3. |
Ferguson
NM, Cummings DA, Fraser C, Cajka JC, Cooley PC, Burke DS. Strategies
for mitigating an influenza pandemic. Nature 2006;442:448-452. |
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| 4. |
Markel
H, Stern AM, Navarro JA, Michaelsen JR, Monto AS, DiGiovanni C. Nonpharmaceutical
influenza mitigation strategies, US communities, 1918-1920 pandemic. Emerg
Infect Dis 2006;12:1961-1964. |
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| 5. |
Inglesby
TV, Nuzzo JB, O’Toole T, Henderson DA. Disease
mitigation measures in the control of pandemic influenza. Biosecur
Bioterr 2006;4:366-375. |
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| Accreditation
Statement · back
to top |
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This
activity has been planned and implemented in accordance with the
Essential Areas and Policies of the Accreditation Council for Continuing
Medical Education through the joint sponsorship of the Johns Hopkins
University School of Medicine, The Institute for Johns Hopkins Nursing
and The University of Tennessee College of Pharmacy. The Johns Hopkins
University School of Medicine is accredited by the ACCME to provide
continuing medical education for physicians.
The Institute for
Johns Hopkins Nursing is accredited as a provider of continuing nursing
education by the American Nursing Credentialing Center's Commission
on Accreditation. |
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| Credit
Designations · back
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Physicians
The Johns Hopkins
University School of Medicine designates this educational activity
for a maximum of 1.0 AMA PRA Category 1 Credit(s)TM.
Physicians should only claim credit commensurate with the extent
of their participation in the activity.
Nurses
This 1.0 contact
hour Educational Activity (Provider Directed/Learner Paced) is provided
by The Institute for Johns Hopkins Nursing. Each newsletter carries
a maximum of 1.0 contact hour or a total of 12.0 contact hours for
the twelve newsletters in this program.
Pharmacists
 This
program is accredited for one hour credit (0.1 CEUs) and is co-sponsored
by the University of Tennessee College of Pharmacy who is accredited
by the Accreditation Council for Pharmacy Education as a provider
of continuing pharmacy education. A statement of CE credit will be
mailed within 4 weeks of successful completion and evaluation of
the program. ACPE Program #064-999-07-277-H01-P.
Grievance Policy: A participant, sponsor, faculty
member or other individual wanting to file a grievance with respect
to any aspect of a program sponsored or co-sponsored by the UTCOP
may contact the Associate Dean for Continuing Education in writing.
The grievance will be reviewed and a response will be returned within
45 days of receiving the written statement. If not satisfied, an
appeal to the Dean of the College of Pharmacy can be made for a second
level of review. |
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| Post-Test
· back
to top |
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| To
take the post-test for eInfluenza Review you will need to visit The
Johns Hopkins University School of Medicine's CME website or The
Institute for Johns Hopkins Nursing. If you have already registered
for another Hopkins CME program at these sites, simply enter the
requested information when prompted. Otherwise, complete the registration
form to begin the testing process. A passing grade of 70% or higher
on the post-test/evaluation is required to receive CME/CNE/CPE credit. |
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| Statement
of Responsibility · back
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| The
Johns Hopkins University School of Medicine and The Institute for
Johns Hopkins Nursing take responsibility for the content, quality,
and scientific integrity of this CME/CNE/CPE activity. |
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| Target
Audience · back
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| This
activity has been developed for the Primary Care Physicians, Internists,
Infectious Disease Specialists, Pharmacists, and Nurses. There are
no fees or prerequisites for this activity. |
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| Learning
Objectives · back
to top |
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| At
the conclusion of this activity, participants should be able
to: |
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Describe
the CDC recommendations for mitigating person-to-person transmission
of pandemic influenza |
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Explain
the criteria proposed to implement the proposed strategies |
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Discuss
the additional research required to develop these initial recommendations |
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| Internet
CME/CNE/CPE Policy · back
to top |
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The
Offices of Continuing Education (CE) at The Johns Hopkins University
School of Medicine, The Institute for Johns Hopkins Nursing and
The University of Tennessee College of Pharmacy are committed to
protect the privacy of its members and customers. The Johns Hopkins
University maintains its Internet site as an information resource
and service for physicians, other health professionals and the public.
The Johns Hopkins
University School of Medicine, The Institute for Johns Hopkins Nursing
and The University of Tennessee College of Pharmacy will keep your
personal and credit information confidential when you participate
in a CE Internet-based program. Your information will never be given
to anyone outside The Johns Hopkins University and The University
of Tennessee College of Pharmacy program. CE collects only the information
necessary to provide you with the service you request. |
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| Faculty
Disclosure · back
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As
a provider accredited by the Accreditation Council for Continuing
Medical Education (ACCME), it is the policy of Johns Hopkins University
School of Medicine to require the disclosure of the existence of
any significant financial interest or any other relationship a faculty
member or a provider has with the manufacturer(s) of any commercial
product(s) discussed in an educational presentation.
The presenting faculty
reported the following:
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John
G. Bartlett, MD has disclosed that he has served on
the HIV Advisory Board for GlaxoSmithKline, Abbott and Bristol-Myers
Squibb. |
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Jonathan
M. Zenilman, MD has disclosed no relationship with
commerical supporters. |
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Jason
E. Farley, PhD(c), MPH, NP has disclosed no relationship
with commerical supporters. |
Guest
Authors Disclosures |
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| Disclaimer
Statement · back
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| The
opinions and recommendations expressed by faculty and other experts
whose input is included in this program are their own. This enduring
material is produced for educational purposes only. Use of Johns
Hopkins University School of Medicine name implies review of educational
format design and approach. Please review the complete prescribing
information of specific drugs or combination of drugs, including
indications, contraindications, warnings and adverse effects before
administering pharmacologic therapy to patients. |
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COMPLETE
THE POST TEST
Step 1.
Click on the appropriate link below. This
will take you to the post-test.
Step 2.
If you have participated in a Johns Hopkins
on-line course, login. Otherwise, please register.
Step 3.
Complete the post-test and course evaluation.
Step 4.
Print out your certificate.
Pharmacy credit is only available via PDF mail-in form:
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