Atlanta, GA…According to new CDC guidance, fully vaccinated people can stop wearing masks in most settings. To find a vaccine near you go to vaccines.gov. The full update on the guidance from the CDC is below the video where Dr. Walensky Announces New CDC Mask Guidance.

Agency Guidance Review
DATE: March 10, 2021
TO: Rochelle P. Walensky, MD, MPH
Director, CDC, and Administrator, ATSDR
FROM: Anne Schuchat, MD (RADM, USPHS, Ret.)
Principal Deputy Director, CDC
SUBJECT: Summary of Guidance Review

BACKGROUND:
As part of your pledge to lead an effort to restore the public’s trust in the CDC, you asked me to begin a
comprehensive review to ensure that all of CDC’s existing guidance related to COVID-19 is evidencebased and free of politics.

In response to the dynamic circumstances of emerging infections and public health emergency
responses, CDC has customarily issued “interim” guidance documents that are updated as new
information and insights are gained, once novel interventions become available including through
emergency use authorization, or once research reveals greater certainty that permits strengthening or
rejecting earlier interim recommendations. CDC staff have developed thousands of documents during
the COVID-19 response, including foundational guidance documents that address major areas of
concern as well as numerous subsidiary tools and resources adapted from the foundational guidance.
At your request, I led a process to rapidly assess the major or foundational guidance the agency had
issued in order to identify primary documents that needed updating or removal. I also sought to identify
practices that could strengthen the transparency of the evidentiary basis for CDC’s COVID-19 guidance.
In addition to my own review, I sought review of the process and results from current and former
Incident Managers and Principal Deputy Incident Managers of CDC’s Emergency Response, as well as key
Center Directors. The review also included a general assessment of the approach to cross-clearance
within the Incident Management Structure’s task forces (Appendix 1) as well as how the CDC website
alerts readers to changes in guidance and relationships between the evidence-base and various
guidance documents.

PROCESS
My review built on processes that were initiated by the CDC’s response leadership toward the end of
last year. From October 2020 through January 2021, CDC COVID-19 response leadership (I.e., Incident
manager and Principal Deputy incident managers) reviewed the existing COVID-19 related guidance
documents, considerations and supporting communication materials for areas that needed critical
updates, based on several factors such as the accumulation of new evidence . The response leaders used
an iterative process which involved requesting that each task force lead review guidance involving their
area of expertise, and prioritizing material for major or minor updates as well as documents that should
be replaced or removed. Building on this work, I gathered additional insights through key informant
interviews with CDC staff, with iterative input from the IMS leaders, as well as input I received from
public health stakeholders concerned about the rationale or evidence-base for some guidance.
Agency Guidance Review

General observations: There were a variety of issues identified including a) guidance that was not
primarily authored by CDC staff; b) reliance on less directive language (e.g., ‘considerations’) than
response leadership felt could be supported by existing evidence; and c) availability of new data or
evolving scientific understanding that necessitated updated recommendations. I also found that some
recommendations were accompanied by science briefs detailing the evidence-base supporting the
guidance, but these supporting science briefs had not yet consistently been produced and/or publicly
posted for each major area of guidance. Response leaders told me they had updated internal clearance
practices to have reviewers more systematically challenge authors’ use of phrases like ‘consider’ or ‘if
feasible.’ The response leadership team had developed a new template for guidance documents. The
document development and clearance procedures were intended to differentiate between CDC
recommendations where a sufficiently robust evidence-base existed vs. documents where limited
evidence existed so that the latter could be repackaged as “resources” rather than guidance.

Major findings
Guidance removed: By the time of my review in late January and February 2021, two documents
developed or finalized outside of the agency had already been removed (“The Importance of Reopening
of America’s Schools this Fall” posted July 23, 2020 – removed October 29, 2020) or replaced (Overview
of Testing for SARS-COV-2 posted August 24, 2020, replaced September 18, 2020). A link to a third
document (“Opening up America Again” which was released on April 16, 2020 through a link posted on
CDC’s web) was removed February 7, 2021 during the process of my review (Table 1).
Guidance updates: The review by the task forces and response leadership identified several areas
where they prioritized development of updated guidance because of evolving research and
observational data from implementation efforts, including: phased prevention linked to epidemiologic
thresholds; K-12 school operational guidance; Institutions of Higher Education guidance; Overview of
testing guidance linked to more targeted specifications for selected settings (e.g., correctional
institutions; non-health care workplaces); duration of exemption from quarantine after natural infection
and after vaccination; mask related guidance (orders such as for Federal property and public corridor
conveyances and updated guidance to incorporate new information on improvement of fit and
filtration), and travel related guidance including the requirement for laboratory testing pre-departure
for international arrivals (Table 2). Several of these guidance documents have been recently released
(Table 3) or are expected to complete interagency review, as appropriate, and be completed in the
weeks ahead.

Guidance related to COVID-19 vaccines: Given the rapidly evolving trial data and evidence-base on
vaccines, a number of guidance documents have been developed related to COVID-19 vaccines, vaccine
prioritization, and clinical considerations in conjunction with the FDA’s issuance of emergency use
authorizations. Multiple recommendations were issued related to vaccines since early December 2020.
The Advisory Committee on Immunization Practices uses a formal evidence to recommendations
process in their reviews and holds public meetings where the evidence is reviewed before deliberation
occurs. This process complements public deliberations carried out by the FDA’s Vaccines and Related
Biological Products Advisory Committee. Despite the transparency and reliance on scientific data
review, public concerns about vaccine recommendations persist, particularly surrounding prioritization
in the setting of supply constraints. CDC has been committed to updating the interim considerations for
Agency Guidance Review
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clarity based on ongoing feedback and expanding evidence. These updates have been vetted with
diverse clinical partners in addition to ACIP members.
Evidence-base: The availability of scientific briefs (Table 4) provides transparency to the evidence-base
that supports updated or new guidance. While the response typically reviews new evidence in the
process of developing guidance and convenes cross-task force deliberations to review the new evidence,
there was not a consistent practice of publicizing the supporting evidence in a scientific brief in
conjunction with every major new guidance. We are now committed to providing updated science
briefs if there is research to inform guidance updates (see recommendations).
Transparency and credibility in dissemination of guidance: A major update to landing pages and
formatting of the CDC’s website for COVID-19 was completed during the time period of my review, and
this has improved usability of the site. While the response had added a search function for COVID-19
guidance documents in July 2020, and the response’s Joint Information Center developed a summary of
guidance documents disseminated to partners on a regular basis, this review suggests that additional
measures would enhance accessibility of guidance updates for stakeholders and the public. As I
conducted my review, I found it difficult to a) tell whether a new document represented a major or very
minor update to an existing guidance and b) decipher the core recommendations in long documents.
While the version date of previous guidance is noted when updates are posted, the crux of what was
new or changed was difficult to find. Further, I determined that a thorough executive summary or
abstract highlighting the core features of a guidance document, and a separate ‘what has changed’
section would help practitioners quickly incorporate new guidance into their ongoing routines without
having to review the entire document. Finally, consumers and the public could be more assured of the
science-base for guidance if CDC routinely provides scientific briefs, provided a landing spot that listed
all recently updated changes or at a minimum, links to appropriate evidentiary support for major new
guidance and guidance changes. Additional information on CDC’s website describing the general
process by which guidance is developed could also support transparency.
Next Steps and Recommendations.

The CDC will finalize production and reviews of remaining prioritized new guidance in the weeks ahead.
In order to strengthen CDC’s scientific rationale and communication for existing and forthcoming
guidance, I recommend:
1. Use of scientific briefs or lists of supporting evidence for major new guidance documents. These
need not be exhaustive but should make the scientific rationale for major changes easily
accessible.
2. Support transparency in messaging related to areas where the evidence-base is not sufficiently
strong or where there are real tradeoffs between theoretic benefits/risks of a course of action
and practical implementation barriers to a course of action.
3. Routinely include an abstract or executive summary which briefly outlines key components of
new guidance.
Agency Guidance Review
4. Routinely provide clear summary of what has changed when updates to guidance are posted,
allowing the public to differentiate major from minor changes and the rationale for changes.
Incorporate more consistent use of hyperlinks for “reusable elements” (e.g., quarantine period,
definition of close contact) that are featured in numerous guidance documents, in order to
assure more systematic updating of all guidance that relies on such concepts which themselves
are occasionally updated.
5. Plan on media and stakeholder briefings when major guidance is issued. This should allow
questions about changes and the scientific rationale to be addressed promptly. Minor guidance
updates can be messaged in conjunction with general media briefings, while major guidance
updates should be accompanied by more complete roll-out plans to address both public and
policymaker concerns and highlight the science or new knowledge that has led to the changes.
6. Plan to review major guidance areas at least every three months during the COVID-19 response
to assess when further changes are needed.
7. Reduce the number of adaptations of guidance documents that CDC issues. Encourage partner
organizations in collaboration with the CDC to prepare such documents derived from CDC’s
foundational guidance. This will conserve CDC’s scientific and technical resources for the most
impactful actions, and permit partners more familiar with each audience to achieve appropriate
language and incorporate real world settings more accurately.
8. To the greatest extent possible, incorporate end user input to guidance products to assure
recommendations are accessible and easily understood in order to foster accelerated uptake.
Agency Guidance Review

Table1. COVID-19 Guidance Documents Removed from CDC Website
Title Date Posted Date Removed
The Importance of Reopening of America’s Schools this Fall July 23, 2020 October 29, 2020
Overview of Testing for SARS-COV-2 August 24, 2020 September 18, 2020
Opening up America Again (link on CDC site) April 16, 2020 February 7, 2021
Table 2. COVID-19 Prioritized Major New or Updated Guidance based on Incident Manager System
Leadership Review, October 2020 through January 2021
Title Released as of
March 8, 2021
Recommendations-Phased Prevention Strategies to Reduce SARS-CoV-2 Transmission1
Operational Strategies for K-12 Schools and Childcare
Scientific Brief: Transmission of SARS-CoV-2 in K-12 schools


Overview of Testing for SARS-CoV-2 Guidance Update
Supporting testing guidance for specific settings:
• Interim Guidance for SARS-CoV-2 Testing in Correctional and Detention Facilities
• Guidance-SARS-CoV-2 Testing Strategy for Select Workplaces
• Updated Guidance-Testing-Screening-Outbreak Response for IHEs
• Interim Guidance for Health Departments for SARS-CoV-2 Testing in Homeless
Shelters and Encampments
Duration of Isolation and Precautions for Adults with COVID-19 
Masking Guidance:
• Federal property
• Public conveyances
• Fit and Increase the Filtration



CDC Guidance for Promoting COVID-19 Safety in Domestic and International Travel for
Sea Travel

COVID-19 Critical Infrastructure Sector Response Planning 
1 Prioritized in Fall 2020. Deprioritized guidance in the context of scaling vaccination. Continuing to assemble
evidence-base for high risk settings.
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Table 3. COVID-19 Major Guidance Documents Released or Updated since January 20, 2021 as of
March 8, 2021
Date Released Title
3/8/21 Interim Public Health Recommendations for Fully Vaccinated People
This is the first set of public health recommendations for fully vaccinated people.
2/16/21 Return to Work Criteria for Healthcare Personnel with SARS-CoV-2 Infection (Interim
Guidance)
Changes to more closely align guidance with updates to the Decision Memo:
HCP who are severely immunocompromised, could remain infectious more than 20
days after symptom onset. Consultation with infectious diseases specialists is
recommended; use of a test-based strategy for determining when these HCP may
return to work could be considered.
2/16/21 Discontinuation of Transmission-Based Precautions and Disposition of Patients with
SARS-CoV-2 Infection in Healthcare Settings
Changes to more closely align guidance with updates to the Decision Memo:
• Patients who are severely immunocompromised could remain infectious
more than 20 days after symptom onset. Consultation with infectious
diseases specialists is recommended; use of a test-based strategy for
determining when to discontinue Transmission-Based Precautions could be
considered.
2/16/21 Interim Clinical Guidance for Management of Patients with Confirmed Coronavirus
Disease (COVID-19)
• New information on potential for under-detection of occult hypoxemia by
pulse oximetry, especially among persons with dark skin
• New information on dermatologic manifestations associated with COVID-19
• New information on prolonged shedding of replication-competent SARSCoV-2 in severely immunocompromised persons
• New information on reports of reinfection with variant viruses
2/12/21 Operational Strategy for K-12 Schools through Phased Mitigation
Updated to incorporate the best available evidence at this time. The indicators and
thresholds in the operational strategy replace the core indicators in the Indicators
for Dynamic School Decision-Making.
2/10/21 Maximizing Fit for Cloth and Medical Procedure Masks to Improve Performance and
Reduce SARS-CoV-2 Transmission and Exposure, 2021
Added new evidence on two ways of improving the fit of medical procedure masks:
fitting a cloth mask over a medical procedure mask, and knotting the ear loops of a
medical procedure mask and then tucking in and flattening the extra material close
to the face. Each modification substantially improved source control and reduced
wearer exposure.
2/5/21 Requirement for Proof of Negative COVID-19 Test or Recovery from COVID-19 for All
Air Passengers Arriving in the United States
Updated to include Order
2/4/21 Requirement for Face Masks on Public Transportation Conveyances and at
Transportation Hubs
Updated to include Order
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Table 4. COVID-19 Science Briefs Containing Evidence-Base in Support of Updated Guidance
Category Title Date Updated
Potential Airborne
Transmission
Science Brief: SARS-CoV-2 and Potential Airborne Transmission 10/5/20
Use of Cloth Masks Science Brief: Community Use of Cloth Masks to Control the
Spread of SARS-CoV-2
11/20/20
Options to reduce
Quarantine
Science Brief: Options to Reduce Quarantine for Contacts of
Persons with SARS-CoV-2 Infection Using Symptom Monitoring
and Diagnostic Testing | CDC
12/2/20
Vaccine Allocation The Advisory Committee on Immunization Practices’ Interim
Recommendation for Allocating Initial Supplies of COVID-19
Vaccine — United States, 2020
12/3/20
Mitigation Summary of Guidance for Public Health Strategies to Address High
Levels of Community Transmission of SARS-CoV-2 and Related
Deaths, December 2020
12/11/20
Pfizer COVID-19
Vaccine
Grading of Recommendations, Assessment, Development, and
Evaluation (GRADE): Pfizer-BioNTech COVID-19 Vaccine
12/13/20
Moderna COVID19 Vaccine
Grading of Recommendations, Assessment, Development, and
Evaluation (GRADE): Moderna COVID-19 Vaccine
12/20/20
Evidence for
Vaccine Allocation
Evidence Table for COVID-19 Vaccines Allocation in Phases 1b and
1c of the Vaccination Program
12/20/20
Emerging SARSCoV-2 Variants
Science Brief: Emerging SARS-CoV-2 Variants | CDC 1/28/21
Transmission of
SARS-CoV-2 in K-12
schools
Science Brief: Transmission of SARS-CoV-2 in K-12 schools 2/12/21
Duration of
Isolation and
Precautions for
Adults with
COVID-19
Interim Guidance on Duration of Isolation and Precautions for
Adults with COVID-19
2/13/21
Janssen COVID-19
Vaccine
Grading of Recommendations, Assessment, Development, and
Evaluation (GRADE): Janssen COVID-19 Vaccine
3/1/21
Fully vaccinated
People
Science Brief: Background Rationale and Evidence for Public Health
Recommendations for Fully Vaccinated People
3/8/21
Agency Guidance Review
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Appendix 1: Task Forces within CDC’s COVID-19 Incident Management Structure, March 2021
Task Force Name
Epidemiology & Surveillance
Data, Analytics & Visualizations
Laboratory & Testing
Global Migration
State, Territorial, Local, Tribal (STLT) Support
International
Community Interventions & Critical Populations
Health Systems & Worker Safety
Vaccine