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

December 20, 2020
Objective

Policy Question:

Which groups should be offered COVID-19 vaccination in Phase 1b & 1c?
 Ensure safety and effectiveness of COVID-19 vaccines

 Reduce transmission, morbidity, mortality of COVID-19 disease

 Help minimize disruption to society and the economy, including maintaining 

healthcare capacity

 Ensure equity in vaccine allocation and distribution

Work Group Considerations: 

Goals of the COVID-19 Vaccine Program
Work Group considerations: Balancing Goals 

Prevention of 

Morbidity & Mortality

Preservation of 

Societal Functioning
Work Group considerations: Balancing Goals 

Prevention of 

Morbidity & Mortality

Preservation of 

Societal Functioning

1a LTCF residents Health care personnel

●Ensure safety and effectiveness of COVID-19 vaccines●

●Ensure equity in vaccine allocation and distribution●
Work Group considerations: Balancing Goals

 10 public ACIP meetings, 28 COVID-19 Work Group meetings

 Evidence: Scientific, Implementation, Ethical

 External Expert Advice

–

–

–

–

–

–

–

National Academies of Science Engineering Medicine

Academic Reports

International Recommendations

 Public Input

Focus groups

Population surveys

Pandemic preparedness

ACIP public comment and federal register
Work Group considerations: Balancing Goals 

Prevention of 

Morbidity & Mortality

Preservation of 

Societal Functioning

1a LTCF residents Health care personnel

1b Persons 75 years and older Frontline Essential Workers

1c

Persons 65-74 years

Persons 16-64 with high-risk

medical conditions

Other Essential Workers

●Ensure safety and effectiveness of COVID-19 vaccines●

●Ensure equity in vaccine allocation and distribution●
Work Group considerations: Balancing Goals 

Prevention of 

Morbidity & Mortality

Preservation of 

Societal Functioning

1a LTCF residents Health care personnel

1b Persons 75 years and older Frontline Essential Workers

1c

Persons 65-74 years

Persons 16-64 with high-risk

medical conditions

Other Essential Workers

●Ensure safety and effectiveness of COVID-19 vaccines●

●Ensure equity in vaccine allocation and distribution●
Phase 1 Phase 2 Phase 3

Phase 1a “Jumpstart Phase”

• High-risk health workers

• First responders

Phase 1b

• People of all ages with 

comorbid and underlying 

conditions that put them 

at significantly higher risk

• Older adults living in 

congregate or 

overcrowded settings

• K-12 teachers and school staff and child 

care workers

• Critical workers in high-risk settings—

workers who are in industries essential to 

the functioning of society and substantially 

higher risk of exposure

• People of all ages with comorbid and 

underlying conditions that put them at 

moderately higher risk

• People in homeless shelters or group 

homes for individuals with disabilities, 

including serious mental illness, 

development and intellectual disabilities, 

and physical disabilities or in recovery, and 

staff who work in such settings

• People in prisons, jails, detention centers, 

and similar facilities, and staff who work in 

such settings

• All older adults not included in Phase 1

• Young adults

• Children

• Workers in industries 

and occupations 

important to the 

functioning of 

society and at 

increased risk of 

exposure not 

included in Phase 1 

or 2

NASEM 

Framework

National Academies of Sciences, Engineering, and Medicine 2020. https://www.nationalacademies.org/our-work/a-framework-for-equitable-allocation-of-vaccine-for-the-novel-coronavirus
Essential Workers* (total ~87M)

Frontline Essential Workers (~30M)

 First Responders (Firefighters, Police) 

 Education (teachers, support staff, daycare)

 Food & Agriculture 

 Manufacturing 

 Corrections workers

 U.S. Postal service workers

 Public transit workers

 Grocery store workers 

Other Essential Workers (~57M)

 Transportation and logistics

 Food Service

 Shelter & Housing (construction)

 Finance

 IT & Communication

 Energy

 Media

 Legal

 Public Safety (Engineers)

 Water & Wastewater

*CISA: Essential Critical Infrastructure Workers: https://www.cisa.gov/news/2020/08/18/cisa-releases-updated-guidance-essential-critical-infrastructure-workers

Frontline Essential Workers: workers who are in sectors essential to the functioning of society and are at 

substantially higher risk of exposure to SARS-CoV-2
Proposed Phases of COVID-19 Vaccination

16-64 years

with high -risk

medical conditions

(>110M)

16-64 years

Without high -risk 

medical conditions

(<86M)

65-74 years (32M)

75+ years (21M)

Essential Workers

LTCF

Phase 1a Phase 1b Phase 1c Phase 2

HCP

Frontline
Allocation of COVID-19 vaccine 

12

Ethics

Science

Implementation

Which groups should be 

recommended to receive 

COVID-19 vaccines in 

Phase 1b & 1c?
Science

Ethics

Science

Implementation
COVID-19 incidence is highest in young adults

*Data sources: CDC COVID-19 data tracker. Population estimates from 2019 US Census Bureau. Data provisional, subject to change.

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

by Age Group – Data through Dec 16, 2020

1135

1944

5489

4671

4543

3993

2977

3147

5064

0 1000 2000 3000 4000 5000 6000

0-4

5-17

18-29

30-39

40-49

50-64

65-74

75-84

85+

COVID-19 Incidence per 100,000 Population

Age Group (Years)
*Data sources: CDC COVID-19 data tracker. Population estimates from 2019 US Census Bureau. Data provisional, subject to change. 

COVID-19 mortality rates are highest in older adults

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

Age Group – Data through Dec 16, 2020

0.3

0.2

2.2

6.3

15.7

50.6

143.5

366.2

1,118.3

0.0 200.0 400.0 600.0 800.0 1,000.0 1,200.0

0-4

5-17

18-29

30-39

40-49

50-64

65-74

75-84

85+

Death Rate per 100,000 Population

Age Group (Years)
Although overall mortality increases with age, the proportion of deaths 

associated with COVID-19 is similar across middle-age and older adults

As of December 16 16 th: https://www.cdc.gov/nchs/nvss/vsrr/covid_weekly/index.htm

0

100000

200000

300000

400000

500000

600000

700000

800000

900000

15–24 25–34 35–44 45–54 55–64 65–74 75–84 85+

Number of deaths

Deaths involving COVID-19 Deaths from all causes

Age Group (years)

9% 9% 10% 11% 10%

Deaths from All Causes and Deaths Involving COVID-19, by Age Group

Data through Dec 16, 2020
Adults 75 years and older account for 25% of COVID-19 

associated hospitalizations

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. 

12%

25%

39%

25%

0 5 10 15 20 25 30 35 40 45

15-34

35-54

55-74

75+

Percent of COVID-19 Hospitalizations

Age Group (Years)

Percent of COVID-19-Associated Hospitalizations, by Age Group

Data through Dec 5, 2020
0

20

40

60

80

100

120

10 15 20 25 30 35 40 45

Hospitalization rates per 100,000

MMWR Week

0-4 yr 5-17 yr 8-49 yr 50-64 yr 65-74 yr 75-84 yr ≥85 yr

Age Group

Data Source: https://gis.cdc.gov/grasp/COVIDNet/COVID19_3.html

COVID-19-Associated Hospitalization Rates per 100,000 population

Preliminary Weekly Rates as of Dec 5, 2020

COVID-19-associated hospitalization rates are highest 

in older adults
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

*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

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

17

Risk of in-hospital death among persons hospitalized for 

COVID-19 increased with age
High seroprevalence 

among many 

frontline essential 

workers groups 

following first wave 

of pandemic in NYC

Percent seropositive for SARS-CoV-2 IgG antibody, by occupation among 

workers in public service agencies — New York City, May–July 2020

Other includes Dietary Service Staff, Environmental Service Staff and participants who selected Other and were not reassigned to an existing category

Other Health includes Student/Trainee, Respiratory Therapist, Occupational/Speech/Physical Therapist, Therapy Aide/Assistant, Pharmacist, Diagnostic Imaging Technician, Phlebotomist, 

Medical Registrar, Orderly, Dietician, Dentist, Clinical Technician, Medical Assistant. Sami et al. Manuscript in preparation. 
Half of essential workers are older than 40 years

1. Data Source: American Community Survey, 2019 2. Data source: 2019 Behavioral Risk Factor Surveillance System

• 8-11% are ≥65 years old1

• >56% of adults 18-64 

years have ≥1 high-risk 

medical condition2
Summary of Work Group interpretation: Modeling 

 In the scenarios considered, differences between strategies is minimal

– Vaccinating older adults first averts slightly more deaths, vaccinating younger adults first 

(essential workers or younger adults with high-risk conditions) averts slightly more 

infections

– Ethical principles and implementation considerations also contribute to selecting the 

optimal sequence in Phase 1b and 1c

 Largest driver of 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 to prevent cases so vaccine can have maximum impact) 

 Vaccine’s ability to prevent transmission will further inform future modeling analysis and 

interpretation

Modeling Strategies for the initial Allocation of SARS-CoV-2 Vaccines https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2020-10/COVID-Biggerstaff.pdf
Impacts of COVID-19 not represented in models:

Late Sequelae of COVID-19

Most commonly reported symptoms include: 

fatigue, dyspnea, cough, arthralgia, and chest pain

More serious complications appear to be less common but have been reported:

 Cardiovascular: myocardial inflammation, ventricular dysfunction

 Respiratory: pulmonary function abnormalities

 Renal: acute kidney injury

 Dermatologic: rash, alopecia

 Neurological: olfactory and gustatory dysfunction, sleep dysregulation, altered cognition, 

memory impairment

 Psychiatric: depression, anxiety, changes in mood

CDC, Late Sequelae of COVID-19 https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-care/late-sequelae.html
Implementation

Ethics

Science

Implementation
Safety is paramount. Vaccine safety standards will not be compromised in 

efforts to accelerate COVID-19 vaccine development or distribution

Inclusive clinical trials. Study participants should reflect groups at risk for 

COVID-19 to ensure safety and efficacy data are generalizable

Efficient Distribution. During a pandemic, efficient, expeditious and 

equitable distribution and administration of approved vaccine is critical

Flexibility. Within national guidelines, state and local jurisdictions should have 

flexibility to administer vaccine based on local epidemiology and demand

ACIP COVID-19 Vaccine Work Group: Proposed Guiding Principles

E

Q

U

I

T

Y
Efficient Distribution. During a pandemic, efficient, expeditious 

and equitable distribution and administration of authorized vaccine 

is critical

Flexibility. Within national guidelines, state and local jurisdictions 

should have flexibility to administer vaccine based on local 

epidemiology and demand

ACIP COVID-19 Vaccine Work Group: Proposed Guiding Principles

E

Q

U

I

T

Y
Feasibility

Adults ≥65 years

 Challenge: long distances to central clinics and high throughput of clinics 

 Older adults report high intent to receive COVID-19 vaccine

 Physician offices, pharmacies and public health clinics are established providers of adult vaccination

 Population surveys report 73% - 82% of respondents supported priority vaccination of 

persons aged ≥65 years/elderly in polls conducted in December 2020 2,3

1. 2. AP-NORC Center for Public Affairs Research. Many remain doubtful about getting COVID-19 vaccine. December 

2020.https://apnorc.org/projects/many-remain-doubtful-about-getting-covid-19-vaccine. 3. ABC/IPSOS poll. December 14, 

2020.https://www.ipsos.com/en-us/news-polls/abc-news-coronavirus-poll.
Feasibility

Essential workers

 Challenge: reaching workers in rural locations, shift workers, those working multiple jobs or 

working in small cohorts 

 Jurisdiction approaches include on site occupational clinics/pharmacies/Health Dept POD 

strike teams

 Population surveys report 68% - 87% of respondents supported prioritization of early 

allocation of COVID-19 vaccine supply to essential workers (eg. police/fire/rescue and 

teachers)1-3

1. The Harris Poll:https://www.axios.com/who-gets-coronavirus-vaccine-first-4ff87ff8-39d7-49d6-8d25-fa2307119235.html. 2. AP-NORC Center for Public Affairs Research. Many 

remain doubtful about getting COVID-19 vaccine. December 2020. https://apnorc.org/projects/many-remain-doubtful-about-getting-covid-19-vaccine. 3. ABC/IPSOS poll. 

December 14, 2020. https://www.ipsos.com/en-us/news-polls/abc-news-coronavirus-poll.
Feasibility

Adults with high-risk medical conditions

 Challenges: determining eligibility & very large group

 Healthcare homes, such as physician offices or pharmacies, could be better suited to verifying 

underlying medical conditions

 Population surveys report 68% - 84% of respondents supported prioritization of early allocation 

of COVID-19 vaccine supply to persons who are high risk because of medical problems1-3

1. The Harris Poll:https://www.axios.com/who-gets-coronavirus-vaccine-first-4ff87ff8-39d7-49d6-8d25-fa2307119235.html. 2. AP-NORC Center for Public Affairs Research. Many 

remain doubtful about getting COVID-19 vaccine. December 2020. https://apnorc.org/projects/many-remain-doubtful-about-getting-covid-19-vaccine. 3. ABC/IPSOS poll. 

December 14, 2020. https://www.ipsos.com/en-us/news-polls/abc-news-coronavirus-poll.
Ethics

Ethics

Science

Implementation
Ethical Principle

Older Adults

Age 75+ years (21M) Age 65-74 Years (32M)

Maximize benefits and 

minimize harms

Reduces morbidity and mortality in 

persons with highest burden of COVID19 hospitalization and death

Reduces morbidity and mortality in 

persons with high burden of COVID19 hospitalization and death

Promote justice

-Will require focused outreach to those who experience barriers to access 

healthcare

-Persons living in multi-generational households may have greater risk of 

exposure

Mitigate Health 

inequities

- Racial and ethnic minority groups under-represented among adults >65

- Racial and ethnic minority persons >65 disproportionate COVID-19 related 

hospitalization and death rates
Ethical Principle

Essential Workers 

Frontline essential workers (~30 M) / Other essential workers (~57M)

Maximize benefits and 

minimize harms

-Essential Workers are at high risk of exposure. Prevention of disease will 

reduce transmission

-Preserves services essential to the COVID-19 response and overall functioning 

of society. “Multiplier effect”

Promote justice

-Workers unable to work from home

-High level of interaction with public or 

others in the workplace

-May be unable to control social 

distancing

-Frequently interact with others in 

the workplace

Mitigate Health 

inequities

-Racial and ethnic minority groups disproportionately represented in many 

essential industries

-~1/4 of essential workers live in low-income families
Ethical Principle

Persons 16-64 with high-risk

medical conditions

(>110 Million)

Maximize benefits and 

minimize harms

Reduces morbidity and mortality in persons with moderate to high burden of 

COVID-19 associated hospitalization and death

Promote justice Will require focused outreach to those with limited or no access to healthcare

Mitigate Health 

inequities

-Increased prevalence of some medical conditions in race/ethnic minority 

groups & persons in rural areas

-Diagnosis of medical conditions requires access to healthcare
Summary of Work Group Considerations
Summary: Work Group considerations

 Scientific, implementation and ethical considerations support inclusion of groups in Phase 1b and 

1c as a balance of prevention of morbidity and mortality and preservation of societal functions

 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, if supply 

exceeds demand

 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, as 

soon as possible
Proposed Phase 1 & 2 allocation, December 2020 

*Accounts for persons recommended in prior phases or overlap within a phase

Phase Groups recommended for vaccination

Number of 

persons in each 

group

(millions)

Number of unique* 

persons in each 

group

(millions)

Total* 

(millions)

1a Health care personnel

Long-term care facility residents

21

3

21

3 24

1b Frontline essential workers 

Persons aged 75 years and older

30

21

30

19 49

1c Persons aged 65-74 years

Persons aged 16-64 years with high-risk conditions

Essential workers not recommended in Phase 1b

32

110

57

28

81

20 129

2 All people aged 16 years and older not in Phase 1, 

who are recommended for vaccination
Proposed Phase 1 & 2 allocation, December 2020 

*Accounts for persons recommended in prior phases or overlap within a phase

Phase Groups recommended for vaccination

Number of 

persons in each 

group

(millions)

Number of unique* 

persons in each 

group

(millions)

Total* 

(millions)

1a Health care personnel

Long-term care facility residents

21

3

21

3 24

1b Frontline essential workers 

Persons aged 75 years and older

30

21

30

19 49

1c Persons aged 65-74 years

Persons aged 16-64 years with high-risk conditions

Essential workers not recommended in Phase 1b

32

110

57

28

81

20 129

2 All people aged 16 years and older not in Phase 1, 

who are recommended for vaccination
Example of Phase 1 & Phase 2 COVID-19 vaccination roll-out
Proposed Phases of COVID-19 Vaccination

16-64 years

with high -risk

medical conditions

(>110M)

16-64 years

Without high -risk 

medical conditions

(<86M)

65-74 years (32M)

75+ years (21M)

Essential Workers

LTCF

Phase 1a Phase 1b Phase 1c Phase 2

HCP

Frontline
ACIP Vote – Interim Recommendation

As an update to ACIP recommendations for vaccination in Phase 1a (health care 

personnel, and long-term care facility residents), if COVID-19 vaccine supply is limited, 

the following groups should be offered vaccination:

Phase 1b: persons aged ≥75 years and frontline essential workers

Phase 1c: persons aged 65–74 years, persons aged 16–64 years with high-risk medical 

conditions, and other essential workers
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