National Center for Immunization & Respiratory Diseases

Trends in COVID-19-Associated Hospitalizations — COVID-19-Associated 

Hospitalization Surveillance Network (COVID-NET), March 2020–February 2023

Christopher A. Taylor, PhD

Epidemiologist, COVID-NET

Coronaviruses and Other Respiratory Viruses Division

National Center for Immunizations and Respiratory Diseases

Centers for Disease Control and Prevention

Advisory Committee on Immunization Practices

February 24, 2023
Weekly Population-Based Rates of COVID-19-Associated Hospitalizations 

among All Ages — COVID-NET, March 2020–February 2023

0

20

40

60

80

100

120

140

3/7/20204/7/20205/7/20206/7/20207/7/20208/7/20209/7/2020

10/7/202011/7/202012/7/2020

1/7/20212/7/20213/7/20214/7/20215/7/20216/7/20217/7/20218/7/20219/7/2021

10/7/202111/7/202112/7/2021

1/7/20222/7/20223/7/20224/7/20225/7/20226/7/20227/7/20228/7/20229/7/2022

10/7/202211/7/202212/7/2022

1/7/2023

Rate per 100,000 population

Week Ending Date

≤17 years 18–49 years 50–64 years 65–74 years ≥75 years

Gray boxes indicate potential reporting delays. Interpretation of trends should be excluded from these weeks. 2
Weekly Population-Based Rates of COVID-19-Associated Hospitalizations 

among Adults Ages ≥18 Years — COVID-NET, March 2020–February 2023

0

20

40

60

80

100

120

140

Rate per 100,000 population

Week Ending Date

March 2020–February 2023 (entire pandemic period)

18–49 years 50–64 years 65–74 years ≥75 years

0

20

40

60

80

100

120

140

Rate per 100,000 population

Week Ending Date

August 2022–February 2023

Gray boxes indicate potential reporting delays. Interpretation of trends should be excluded from these weeks. 3
Weekly Population-Based Rates of COVID-19-Associated Hospitalizations among 

Children and Adolescents Ages ≤17 Years — COVID-NET, March 2020–February 2023

0

10

20

30

40

50

60

70

80

90

Rate per 100,000 population

Week Ending Date

August 2022–February 2023

0

10

20

30

40

50

60

70

80

90

Rate per 100,000 population

Week Ending Date

March 2020–February 2023 (entire pandemic period)

<6 months 6 months–<2 years 2–4 years 5–11 years 12–17 years

Gray boxes indicate potential reporting delays. Interpretation of trends should be excluded from these weeks. 4
Weekly Proportions of COVID-19-Associated Hospitalizations by 

Adult Age Group — COVID-NET, March 2020–February 2023

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

3/7/2020

4/11/20205/16/20206/20/20207/25/20208/29/202010/3/202011/7/2020

12/12/2020

1/16/20212/20/20213/27/2021

5/1/20216/5/2021

7/10/20218/14/20219/18/2021

10/23/202111/27/2021

1/1/20222/5/2022

3/12/20224/16/20225/21/20226/25/20227/30/2022

9/3/2022

10/8/2022

11/12/202212/17/2022

1/21/2023

March 2020–February 2023 (entire pandemic period)

18–49 years 50–64 years 65–74 years ≥75 years

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

8/6/2022

8/20/2022

9/3/2022

9/17/202210/1/2022

10/15/202210/29/202211/12/202211/26/202212/10/202212/24/2022

1/7/2023

1/21/2023

2/4/2023

August 2022–February 2023

40% of hospitalizations are

in adults ages ≥75 years.

5
Weekly Proportions of COVID-19-Associated Hospitalizations by 

Pediatric Age Group — COVID-NET, March 2020–February 2023

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

3/7/2020

4/11/20205/16/20206/20/20207/25/20208/29/202010/3/202011/7/2020

12/12/2020

1/16/20212/20/20213/27/2021

5/1/20216/5/2021

7/10/20218/14/20219/18/2021

10/23/202111/27/2021

1/1/20222/5/2022

3/12/20224/16/20225/21/20226/25/20227/30/2022

9/3/2022

10/8/2022

11/12/202212/17/2022

1/21/2023

March 2020–February 2023 (entire pandemic period)

<6 months 6 months–<2 years 2–4 years 5–11 years 12–17 years

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

8/6/2022

8/20/2022

9/3/2022

9/17/202210/1/2022

10/15/202210/29/202211/12/202211/26/202212/10/202212/24/2022

1/7/2023

1/21/2023

2/4/2023

August 2022–February 2023

6
Proportions of COVID-19-Associated Hospitalizations with COVID-19 as a Likely Reason for 

Admission by Age and Variant Predominance Period — COVID-NET, June 2020–November 2022

0

10

20

30

40

50

60

70

80

90

100

Total 0–4 years 5–11 years 12–17 years 18–49 years 50–64 years ≥65 years

Weight % of hospitalizations

Period of variant predominance

Pre-Delta (6/1/20–6/19/21)

Delta (6/20–12/18/21)

Omicron BA.1 (12/19/21–3/19/22)

Omicron BA.2 (3/20–6/18/22)

Omicron BA.5 and later (6/19–11/30/2022)

• Many children ages 

≤4 years and adults 

ages ≥50 years are 

still admitted for 

COVID.

• Adolescents and 

younger adults (ages 

12–49 years) are 

less likely to be 

admitted for COVID.

7
Underlying Medical Conditions among Non-Pregnant Adults 

Ages ≥18 Years — COVID-NET, June–November 2022

68.6

54.6

35.0 32.5 30.7

24.6

17.5 14.9

9.7

5.3

0

10

20

30

40

50

60

70

80

Weighted % of hospitalizations

Data are limited to hospitalizations where COVID-19 is a likely primary reason for admission.

96% of hospitalized adults have

≥1 underlying medical condition.

8
Underlying Medical Conditions among Children and Adolescents 

Ages ≤17 Years — COVID-NET, June–November 2022

13.1

11.2

8.8 8.8

7.9

6.7 6.6 6.4

5.3

3.5 3.4

2.6 2.2

0

2

4

6

8

10

12

14

Weighted % of hospitalizations

Data are limited to hospitalizations where COVID-19 is a likely primary reason for admission.

49% of hospitalized children and 

adolescents have no underlying 

medical conditions.

9
Underlying Medical Conditions among Children and 

Adolescents by Age Group — COVID-NET, June–November 2022

0

5

10

15

20

25

30

<2 years 2–4 years 5–11 years 12–17 years

Weighted % of hospitalizations

Asthma Prematurity Feeding tube dependence

Obesity Chronic lung disease, not including asthma Immunocompromising condition

Gastrointenstinal/liver Disease Blood disorders Chronic lung disease of prematurity

Autoimmune/inflammatory disease Abnormality of airway Diabetes

Data are limited to hospitalizations where COVID-19 is a likely primary reason for admission. 10
Vaccination Status by Age Group among Non-Pregnant Adults 

Ages ≥18 Years — COVID-NET, October–November 2022

Data are limited to hospitalizations where COVID-19 is a likely primary reason for admission. Unvaccinated: No recorded doses of COVID-19 vaccine. Vaccinated, but no bivalent booster: 

Completed a primary series with or without ≥1 booster dose but did not receive an updated bivalent booster dose. Updated bivalent booster: Received updated bivalent booster dose. Partially 

vaccinated: Received at least one dose of COVID-19 but was not considered fully vaccinated at the time of a positive SARS-CoV-2 test. Persons with unknown vaccination status are excluded. 

58.2

50.4

34.1

23.1

15.0 12.5

40.3

42.4

58.0

66.9 79.6

76.5

5.4 2.7 3.4

2.7 8.0

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

5–11 years 12–17 years 18–49 years 50–64 years 65–74 years ≥75 years

Percent of hospitalizations

Unvaccinated Vaccinated, but no bivalent booster Updated bivalent booster Partially vaccinated

11
Monthly Age-Adjusted Rates of Lab-Confirmed Hospitalizations by Vaccination Status 

among Adults Ages ≥18 Years — COVID-NET, January 2021–December 2022

0

100

200

300

400

500

600

700

Rate per 100,000 population

Month of Admission

Unvaccinated Primary series Primary series & ≥1 booster

Primary series & ≥2 boosters Vaccinated, no bivalent booster Updated bivalent booster

Data are based on all hospitalizations regardless of reason for admission. Unvaccinated: No recorded doses of COVID-19 vaccine. Primary series ± ≥1 booster: Completed a primary series with or without ≥1 

booster dose but did not receive an updated bivalent booster dose. Vaccinated, but no bivalent booster: Completed a primary series with or without ≥1 booster dose but did not receive an updated bivalent 

booster dose. Updated bivalent booster: Received updated bivalent booster dose. Persons with partial or unknown vaccination status are excluded. See https://covid.cdc.gov/covid-data-tracker/#covidnethospitalizations-vaccination for complete definitions of vaccination categories. 

In December 2022, compared to adults 

who received an updated bivalent booster 

dose, the monthly rates of hospitalization 

were

- 16x higher among unvaccinated and 

- 2.6x higher in vaccinated adults 

without an updated booster dose.

12
Acknowledgments

Coronaviruses and Other Respiratory 

Viruses Division (CORVD) (proposed):

RESP-NET Team (COVID-NET/RSV-NET):

• Fiona Havers

• Huong Pham

• Michael Whitaker

• Kadam Patel

• Jenny Milucky

• Onika Anglin

• Bhoomija Chatwani

Many others in CORVD....

 State, Local, and Territorial 

health Department partners

 RESP-NET partners

Thank you.
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.