For more information: www.cdc.gov/COVID19

Phased Allocation 

of COVID-19 Vaccines

ACIP COVID-19 Vaccines Work Group

Kathleen Dooling, MD, MPH

ACIP meeting

November 23, 2020
Objective

 Select groups for COVID-19 vaccine allocation in

Phase 1a, Phase 1b & Phase 1c
Allocation of COVID-19 vaccine 

3

Ethics

Science

Implementation

Policy Question #2

Which groups should be 

recommended to receive 

COVID-19 vaccine ‘X’ during 

Phase 1?
Allocation of initial COVID-19 vaccine: Phase 1

4

Ethics

Science

Science:

 COVID-19 disease burden 

 Balance of benefits & harms

of vaccine

Implementation
Allocation of initial COVID-19 vaccine: Phase 1

5

Ethics

Science

Implementation:

 Values of target group

 Feasibility

Implementation
Allocation of initial COVID-19 vaccine: Phase 1

6

Ethics

Science

Ethical Principles:

 Maximize benefits &

minimize harms

 Promote justice 

 Mitigate health inequities

 Promote transparency

Implementation
Proposed Groups for Phase 1 vaccination 

Healthcare 

personnel 

~21M

Essential workers

~87M

High-Risk Medical Conditions

>100M

Adults ≥ 65 years old

~53M

August ACIP meeting

Phase 1a:

-Healthcare Personnel

Phase 1b:

-Essential Workers

-High-Risk Med Conditions

-Adults ≥ 65 years old
Proposed groups for Phase 1 vaccination 

Healthcare Personnel 1

(~21million)

Essential Workers

(non-healthcare) 1

(~87 million)

Adults with high -risk

medical conditions 2

(>100 Million)

Adults age

≥65 years3

(53 Million)

Examples

Hospitals

Long-term care facilities

Outpatient

Home health care

Pharmacies

EMS

Public health

Food & Agriculture

Food Service

Transportation

Education

Energy

Police

Firefighters

Manufacturing

IT & Communication

Water & Wastewater

Obesity

Severe Obesity

Diabetes

COP

Heart Condition

Chronic kidney

Cancer

Smoking

Solid Organ Transplant

Sickle cell disease

Community Dwelling

Congregate ~3M4

-Skilled Nursing

Facility (~1.3 M)

-Assisted living

Facilities (~0.8 M)

-Residential care 

communities (~0.6 M)

-HUD Senior 

Housing (~0.3M)

1. https://www.cisa.gov/publication/guidance -essential-critical-infrastructure-workforce

2. https://www.cdc.gov/coronavirus/2019 -ncov/need-extra-precautions/people-with -medical conditions.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fcoronavirus%2F2019-

ncov%2Fneed-extra-precautions%2Fgroups-at-higher-risk.html

3. United States Census Bureau https://www.census.gov/topics/population/older -aging.html

4. Vital and Health Statistics, Series 3, Number 43 (cdc.gov)
Summary of Work Group Considerations supporting 

vaccinating healthcare personnel in Phase 1a

Science

 As of Nov 21, at least 228,503 confirmed COVID-19 cases among HCP, with 822 deaths1

 COVID-19 exposure (inside and outside the healthcare setting) results in absenteeism due to 

quarantine, infection and illness. Vaccination has the potential to reduce HCP absenteeism 

 LTCF modeling demonstrates more cases and death averted at the facility by vaccinating staff 

compared to vaccinating residents2

Implementation

 Acute care HCPs have high uptake of influenza vaccine3– high vaccine acceptance

 Many acute healthcare facilities have the equipment and expertise to carry out large scale 

vaccination with a vaccine that requires ultra-cold storage

Ethics

 Preserves health care services essential to the COVID-19 response and the overall health care system

 HCP group is inclusive of all job types in healthcare settings and is racially and ethnically diverse 

1. https://covid.cdc.gov/covid-data-tracker/#health-care-personnel

2. Slayton, Modeling Allocation Strategies for the initial SARS-CoV-2 Vaccine Supply, ACIP Aug 21, 2020, https://www.cdc.gov/vaccines/acip/meetings/slides-2020-08.html

3. Influenza Vaccination Coverage Among Health Care Personnel- United States, 2018-2019 Influenza Season, https://www.cdc.gov/vaccines/acip/meetings/slides-2020-08.html
Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Science ? ? ?

Implementation ? ? ?

Ethics ? ? ?
Science

Ethics

Science

Implementation
COVID-19 incidence is highest in young adults

727.4

949.3

1830.4

3965.2

3236.3

3073.3

2526.5

2009

2949.9

0 500 1000 1500 2000 2500 3000 3500 4000 4500

0 - 5

6 - 13

14 - 17

18 - 24

25 - 34

35 - 54

55 - 64

65 - 79

80+

COVID-19 Incidence per 100,000 Population

Age Group (Years)

National Estimate of COVID-19 Incidence per 100,000 Population, 

by Age Group – Data through Nov 16, 2020

*Data sources: CDC COVID-19 case reports from jurisdictions. Population estimates from 2019 US Census Bureau. Data provisional, subject to change, incomplete for some jurisdictions. Age missing for 1% of case 

reports
*Data sources: CDC COVID-19 case reports from jurisdictions. Population estimates from 2019 US Census Bureau. Data provisional, subject to change, incomplete for some jurisdictions. Age missing for 21% of deaths. No 

deaths have been reported since 11/13/2020. 

COVID-19 mortality rates are highest in older adults

0.2

0.1

0.2

1.3

3.3

15.2

51.5

149

648.8

0 100 200 300 400 500 600 700

0 - 5

6 - 13

14 - 17

18 - 24

25 - 34

35 - 54

55 - 64

65 - 79

80+

Death Rate per 100,000 Population 

Age Group (Years)

National Estimate of COVID-19 Deaths per 100,000 Population, by 

Age Group – Data through Nov 13, 2020
The majority of COVID-associated hospitalized patients older 

than 75 years, were admitted from a LTCF*

2.6 2.3

5.3

13.5

31.4

48.7

65.9

0

10

20

30

40

50

60

70

18-29 30-39 40-49 50-64 65-74 75-84 85+

Weighted Percent

Proportion of COVID-associated hospitalized patients admitted from a LTCF*

by age group, COVID-NET, March 1-May 31, 2020

Age Group (Years)

*LTCF= Nursing home/skilled nursing facility, rehabilitation facility, assisted living/residential care, LTACH, group home/retirement, psychiatric facility, or other long-term care facility

Data Source: COVID-19 associated hospitalizations reported to Coronavirus Disease 2019 (COVID-19)-Associated Hospitalization Surveillance Network (COVID-NET) surveillance system. COVID-NET is a 

population-based surveillance system that collects data on laboratory-confirmed COVID-19-associated hospitalizations among children and adults through a network of over 250 acute-care hospitals in 14 states. 
Unadjusted and Adjusteda Rate Ratios for Number of Underlying Medical Conditions

and COVID-19-Associated Hospitalization, COVID-NET March 1- June 23, 2020

Unadjusted Rate Ratio (95%CI) Adjusted Rate Ratioa (95%CI)

Number of conditionsb

1 2.8 (2.7, 3.1) 2.5 (2.1, 3.0)

2 5.6 (5.2, 6.1) 4.5 (3.7, 5.5)

3+ 7.2 (6.6, 7.9) 5.0 (3.9, 6.3)

Age 45-64 yearsc ----- 1.8 (1.5, 2.2)

Age 65+ yearsc ----- 2.6 (2.1, 3.1)

Male sexd ----- 1.2 (1.1, 1.4)

Non-Hispanic blacke ----- 3.9 (3.3, 4.7)

Other race/ethnicitye ----- 3.3 (2.8, 3.9)

CI: Confidence Interval; COVID-NET: Coronavirus Disease 2019-Associated Hospitalization Surveillance Network aModel for number of conditions (variable) is adjusted for age, sex, and race/ethnicity

bReference group is no underlying medical condition; Number of conditions is a sum of underlying medical conditions excluding hypertension; the most recent 

year of available BRFSS data for hypertension was 2017.

c

Reference group is 18-44 years 

dReference group is female

eReference group is non-Hispanic white 

Risk for COVID-19 associated hospitalization increased with 

the number of underlying medical conditions

Ko, Sept 2020, doi: 10.1093/cid/ciaa1419
Risk of in-hospital death among patients with COVID-19 associated hospitalization, 

COVID-NET March 1 - May 2, 2020 

85+ years vs 18–39 years

75–84 years vs 18–39 years

65–74 years vs 18–39 years

50–64 years vs 18–39 years

Male

Immunosuppression

Renal disease

Chronic Lung Disease

Cardiovascular Disease

Neurologic disorder

Diabetes

10.98

7.67

5.77

3.11

1.3

1.39

1.33

1.31

1.28

1.25

1.19

-5 0 5 10 15 20

Adjusted Rate Ratios and 95% Confidence Intervals

Among persons hospitalized for COVID-19, risk of in-hospital 

death increased with age

*COVID-NET Surveillance; Final model adjusted for age, sex, race/ethnicity, smoker, hypertension, obesity, diabetes, chronic lung disease, cardiovascular disease, neurologic 

disease, renal disease, immunosuppression, hematologic disorders, and rheumatologic or autoimmune disease. Kim et al, 2020, https://academic.oup.com/cid/advancearticle/doi/10.1093/cid/ciaa1012/5872581 17
Older adults in congregate settings are 

disproportionately affected by COVID-19

 Long-Term Care Facility (LTCF) residents and staff accounted for 6% of cases and 39% 

of deaths in the U.S.1 (Nov 6, 2020) 

– Skilled Nursing Facilities (~1.3M)

• ~470,000 confirmed + probable cases (as of Nov 8, 2020)2

• >67,000 deaths

– Assisted Living Facilities (~0.8M)

• 27,965 confirmed + suspected cases (as of Oct 15/2020, based on 23 states3)

• 5,469 deaths (as of Oct 15/2020, based on 20 states3)

1. Kaiser Family Foundation. State data and policy actions to address coronavirus: COVID -19: metrics by state. San Francisco, CA: K aiser Family Foundation; 2020. 

https://www.kff.org/health -costs/issue-brief/ state-data-and-policy-actions-to-address-coronavirus/#long-term-carecases-deaths 

2. CMS COVID-19 data: https://data.cms.gov/stories/s/COVID-19-Nursing-Home-Data/bkwz-xpvg/

3. Yi SH, See I, Kent AG, et al. Characterization of COVID -19 in Assisted Living Facilities — 39 States, October 2020. MMWR Morb Mortal WklyRep 2020;69:1730–1735. DOI: 

http://dx.doi.org/10.15585/mmwr.mm6946a3
Modeling: What is the potential impact on 

preventing COVID-19 infections and deaths, of 

initially allocating vaccine to one of the following 

groups after vaccinating healthcare personnel in 

Phase 1a?

Updated: 90% VE (younger and older adults)

Biggerstaff, Modeling Strategies for the Initial Allocation of SARS-CoV-2 Vaccines, Oct ACIP: 

https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2020-10/COVID-Biggerstaff.pdf
~1%

Population-Wide Averted Infections:

Infection-Blocking Vaccine





~3%

Initial Phase 1b Target:

Age ≥65

High-Risk Adults

Essential Workers

Initially vaccinating high-risk adults or 

essential workers in Phase 1b averts 

approximately 1–3% more infections, 

compared to targeting age ≥65

– This difference is greatest in the 

scenario where the vaccine is 

introduced before incidence 

peaks

Findings are robust to assumptions of 

reduced VE in older populations
Population-Wide Averted Deaths:

Infection-Blocking Vaccine

Initial Phase 1b Target:

Age ≥65

High-Risk Adults

Essential Workers

~0.5%

~2%

 Initially vaccinating age ≥65 in Phase 

1b averts approximately 0.5–2% more 

deaths, compared to targeting highrisk adults or essential workers

– As before, this difference is 

greatest in the scenario where 

the vaccine is introduced before 

incidence peaks
Population-Wide Averted Deaths:

Disease-Blocking Vaccine

Initial Phase 1b Target:

Age ≥65

High-Risk Adults

Essential Workers

~2%

~6.5%

 Initially vaccinating age ≥65 in 

Phase 1b averts approximately 

2–6.5% more deaths, compared 

to targeting high-risk adults or 

essential workers

– As before, this difference is 

greatest in the scenario 

where the vaccine is 

introduced before incidence 

peaks

 Findings robust to assumptions 

of reduced VE in older 

populations but percentage 

averted drops
Summary of Work Group interpretation: Modeling 

 Differences between the 3 strategies is minimal

–

–

–

–

Ethical principles and implementation considerations may greatly contribute to 

selecting the optimal sequence in Phase Ib

 Largest impact in averted deaths and infections is the timing of vaccine introduction in 

relation to increases in COVID-19 cases

Emphasizes the need to continue non-pharmaceutical interventions (e.g. wearing a 

mask, social distancing) 

 Factors will inform interpretation of modeling data

VE in older adults

Vaccine’s ability to prevent asymptomatic infection & transmission
Work Group assessment: Science

Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Science +++ +++ +++

Implementation

Ethics
Implementation

Ethics

Science

Implementation
24

18

19

21

18

21

25

18

19

21

20

20

21

23

22

23

22

22

30

40

40

34

41

37

0% 20% 40% 60% 80% 100%

≥65 years old

<65 years old

No HR condition

≥1 high-risk condition

Essential (non-HCP)

Non-essential workers

Absolutely certain Very likely Somewhat likely Not likely

*

Intent to receive COVID-19 vaccine, September, 2020 

*

* Statically significant at p<0.05 of “not likely” response vs comparator 

Source: Probability-based internet panel survey of 3,541 adults ≥18 years old, conducted Sept. 3-Oct. 1, 2020. CDC, unpublished data. 
Survey respondents supported early allocation of 

COVID-19 vaccine to groups proposed for Phase 1

Which of the following groups should receive priority when a COVID-19 vaccine is available?

The Harris Poll, n=1399 U.S. Adults, August 14-16, 2020

16

28

34

44

56

60

68

71

73

0 10 20 30 40 50 60 70 80

Young adults (18-30)

Children

Higest incidence areas

Teachers

Fire/Rescue/Police

Essential workers

Immunocompromised people

Seniors (age 55+)

Healthcare Workers

Source: https://theharrispoll.com/americans-want-high-risk-people-to-get-a-coronavirus-vaccine-first/
Feasibility

Essential workers

 Challenging to reach workers in rural locations, shift workers, those with multiple jobs or working in 

small cohorts 

 Jurisdictions approaches include on site occupational clinics/pharmacies/Health Dept POD strike teams

 Most jurisdictions have an allocation “microplan” which includes prioritization among non-healthcare 

essential workers when vaccine supply is limited

Adults with high-risk medical conditions

 Determining eligibility: healthcare homes, such as provider offices or pharmacies, could be better suited 

to verifying underlying medical conditions

 Minimum size of vaccine orders and storage/handling may preclude involvement of small clinics

Adults ≥65 years

 Long distances to central clinics and high throughput of clinics 

 Pharmacy program already established to reach LTCF residents
Work Group assessment: Implementation

Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age 

≥65 years

(53 Million)

Values of target 

group + ++ +++

Feasibility ++ + ++
Overall

Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Science +++ +++ +++

Implementation ++ ++ +++

Ethics
Ethics

Ethics

Science

Implementation
Ethical 

Principle

Essential Workers

(non-healthcare)

(~87 million)

Adults with high-risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Maximize 

benefits and 

minimize 

harms

Preserves services essential to the 

COVID-19 response and overall 

functioning of society

“Multiplier effect”

Reduces morbidity and mortality in 

persons with high burden of COVID19 disease and death

Reduces morbidity and 

mortality in persons with 

highest burden of COVID-19 

hospitalization and death

Promote 

justice

-Workers unable to work from 

home (exposure risk)

-Promotes access to vaccine and 

may reduce barriers for workers 

with low vaccine uptake

Will require focused outreach to 

those with limited or no access to 

healthcare

Will require focused outreach 

to those who experience 

barriers to access healthcare

Mitigate 

Health 

inequities

-Racial and ethnic minority 

groups disproportionately 

represented in many essential 

industries

-~1/4 of essential workers live in 

low-income families

Increased prevalence of some 

medical conditions in race/ethnic 

minority groups & persons in rural 

areas

-Diagnosis of medical conditions 

requires access to healthcare

-Highest incidence and 

mortality in congregate living

--Racial and ethnic minority 

groups under-represented 

among adults >65

McClung N, Chamberland M, Kinlaw K, et al. The Advisory Committee on Immunization Practices’ Ethical Principles for Allocatin g Initial Supplies of COVID-19 Vaccine — United States, 2020. 

MMWR Morb Mortal Wkly Rep. ePub: 23 November 2020. DOI: http://dx.doi.org/10.15585/mmwr.mm6947e3external icon
Work Group assessment: Ethics

Ethical Principle

Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Maximize benefits & 

minimize harms +++ ++ +++

Promote justice +++ ++ ++

Mitigate health 

inequities +++ + +
Work Group assessment: Overall

Essential Workers

(non-healthcare)

(~87 million)

Adults with high -risk

medical conditions

(>100 Million)

Adults age

≥65 years

(53 Million)

Science +++ +++ +++

Implementation ++ ++ +++

Ethics +++ + +
Work Group Proposed Interim Phase 1 Sequence

Phase1c

Adults with high -risk medical conditions 

Adults 65+

Phase 1b

Essential workers 

(examples: Education Sector, Food & Agriculture, Utilities, 

Police, Firefighters, Corrections Officers, Transportation)

Phase 1a

HCP

LTCF residents

Time
Example of a possible Phase 1 sequence
Additional Work Group considerations

 This represents an interim Phase 1 sequence– allocation policy will need to be 

dynamic and adapt as new information such as vaccine performance and supply and 

demand become clear

 Gating criteria will be necessary to move expeditiously from one Phase to the next, 

as demand saturates

 Reaching essential workers (non-healthcare personnel) will require jurisdictions to 

identify critical sectors at risk and optimal strategies to reach them

 Following vaccination, measures to stop the possible spread of SARS-CoV-2, such as 

masks and social distancing, will still be needed 

 The U.S. government is committed to making COVID-19 vaccines available to all 

residents who want them, as soon as possible
Proposed Interim Phase 1 Sequence

Phase1c

Adults with high -risk medical 

conditions 

Adults 65+

Phase 1b

Essential workers 

Phase 1a

HCP

LTCF residents

1) Do ACIP members agree with 

healthcare personnel and LTCF 

residents in Phase 1a? 

2) Do ACIP members agree with 

essential workers (non healthcare) 

in Phase 1b?

3) Do ACIP members agree with 

adults with high -risk medical 

conditions and adults 65 years and 

older in Phase 1c?
Proposed Interim Phase 1 Sequence

Phase1c

Adults with high -risk medical 

conditions 

Adults 65+

Phase 1b

Essential workers 

Phase 1a

HCP

LTCF residents

1) Do ACIP members agree with 

healthcare personnel and LTCF 

residents in Phase 1a? 

2) Do ACIP members agree with 

essential workers (non -healthcare) 

in Phase 1b?

3) Do ACIP members agree with 

adults with high -risk medical 

conditions and adults 65 years and 

older in Phase 1c?
Proposed Interim Phase 1 Sequence

Phase1c

Adults with high -risk medical 

conditions 

Adults 65+

Phase 1b

Essential workers 

Phase 1a

HCP

LTCF residents

1) Do ACIP members agree with 

healthcare personnel and LTCF 

residents in Phase 1a? 

2) Do ACIP members agree with 

essential workers (non healthcare) 

in Phase 1b?

3) Do ACIP members agree with 

adults with high -risk medical 

conditions and adults 65 years and 

older in Phase 1c?
For more information, contact CDC

1-800-CDC-INFO (232-4636)

TTY: 1-888-232-6348 www.cdc.gov

The findings and conclusions in this report are those of the authors and do not necessarily represent the 

official position of the Centers for Disease Control and Prevention.

Thank you