Number needed to vaccinate with a COVID-19 booster to prevent a COVID-19-associated hospitalization during SARS-CoV-2 Omicron BA.1 variant predominance, December 2021-February 2022, VISION Network: a retrospective cohort study

Katherine Adams; John J Riddles; Elizabeth A K Rowley; Shaun J Grannis; Manjusha Gaglani; Bruce Fireman; Emily Hartmann; Allison L Naleway; Edward Stenehjem; Alexandria Hughes; Alexandra F Dalton; Karthik Natarajan; Kristin Dascomb; Chandni Raiyani; Stephanie A Irving; Chantel Sloan-Aagard; Anupam B Kharbanda; Malini B DeSilva; Brian E Dixon; Toan C Ong; Jean Keller; Monica Dickerson; Nancy Grisel; Kempapura Murthy; Juan Nanez; William F Fadel; Sarah W Ball; Palak Patel; Julie Arndorfer; Mufaddal Mamawala; Nimish R Valvi; Margaret M Dunne; Eric P Griggs; Peter J Embi; Mark G Thompson; Ruth Link-Gelles; Mark W Tenforde

doi:10.1016/j.lana.2023.100530

Number needed to vaccinate with a COVID-19 booster to prevent a COVID-19-associated hospitalization during SARS-CoV-2 Omicron BA.1 variant predominance, December 2021-February 2022, VISION Network: a retrospective cohort study

Lancet Reg Health Am. 2023 Jul:23:100530. doi: 10.1016/j.lana.2023.100530. Epub 2023 Jun 14.

Authors

Katherine Adams¹, John J Riddles², Elizabeth A K Rowley², Shaun J Grannis^{3

4}, Manjusha Gaglani^{5

6}, Bruce Fireman⁷, Emily Hartmann⁸, Allison L Naleway⁹, Edward Stenehjem¹⁰, Alexandria Hughes², Alexandra F Dalton¹, Karthik Natarajan^{11

12}, Kristin Dascomb¹⁰, Chandni Raiyani⁵, Stephanie A Irving⁹, Chantel Sloan-Aagard^{8

13}, Anupam B Kharbanda¹⁴, Malini B DeSilva¹⁵, Brian E Dixon^{3

16}, Toan C Ong¹⁷, Jean Keller², Monica Dickerson¹, Nancy Grisel¹⁰, Kempapura Murthy⁵, Juan Nanez⁸, William F Fadel^{3

16}, Sarah W Ball², Palak Patel¹, Julie Arndorfer¹⁰, Mufaddal Mamawala⁵, Nimish R Valvi³, Margaret M Dunne², Eric P Griggs¹⁸, Peter J Embi^{3

19}, Mark G Thompson¹, Ruth Link-Gelles¹⁸, Mark W Tenforde¹

Affiliations

¹ Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
² Westat, Rockville, MD, USA.
³ Center for Biomedical Informatics, Regenstrief Institute, Indianapolis, IN, USA.
⁴ School of Medicine, Indiana University, Indianapolis, IN, USA.
⁵ Baylor Scott & White Health, Temple, TX, USA.
⁶ Texas A&M University College of Medicine, Temple, TX, USA.
⁷ Kaiser Permanente Vaccine Study Center, Kaiser Permanente Northern California Division of Research, Oakland, CA, USA.
⁸ Paso del Norte Health Information Exchange (PHIX), El Paso, TX, USA.
⁹ Kaiser Permanente Center for Health Research, Portland, OR, USA.
¹⁰ Division of Infectious Diseases and Clinical Epidemiology, Intermountain Healthcare, Salt Lake City, UT, USA.
¹¹ Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY, USA.
¹² NewYork-Presbyterian Hospital, New York, NY, USA.
¹³ Brigham Young University Department of Public Health, Provo, UT, USA.
¹⁴ Children's Minnesota, Minneapolis, MN, USA.
¹⁵ HealthPartners Institute, Minneapolis, MN, USA.
¹⁶ Fairbanks School of Public Health, Indiana University, Indianapolis, IN, USA.
¹⁷ School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
¹⁸ Coronavirus and Other Respiratory Viruses Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, USA.
¹⁹ Vanderbilt University Medical Center, Nashville, TN, USA.

Abstract

Background: Understanding the usefulness of additional COVID-19 vaccine doses-particularly given varying disease incidence-is needed to support public health policy. We characterize the benefits of COVID-19 booster doses using number needed to vaccinate (NNV) to prevent one COVID-19-associated hospitalization or emergency department encounter.

Methods: We conducted a retrospective cohort study of immunocompetent adults at five health systems in four U.S. states during SARS-CoV-2 Omicron BA.1 predominance (December 2021-February 2022). Included patients completed a primary mRNA COVID-19 vaccine series and were either eligible to or received a booster dose. NNV were estimated using hazard ratios for each outcome (hospitalization and emergency department encounters), with results stratified by three 25-day periods and site.

Findings: 1,285,032 patients contributed 938 hospitalizations and 2076 emergency department encounters. 555,729 (43.2%) patients were aged 18-49 years, 363,299 (28.3%) 50-64 years, and 366,004 (28.5%) ≥65 years. Most patients were female (n = 765,728, 59.6%), White (n = 990,224, 77.1%), and non-Hispanic (n = 1,063,964, 82.8%). 37.2% of patients received a booster and 62.8% received only two doses. Median estimated NNV to prevent one hospitalization was 205 (range 44-615) and NNV was lower across study periods for adults aged ≥65 years (110, 46, and 88, respectively) and those with underlying medical conditions (163, 69, and 131, respectively). Median estimated NNV to prevent one emergency department encounter was 156 (range 75-592).

Interpretation: The number of patients needed to receive a booster dose was highly dependent on local disease incidence, outcome severity, and patient risk factors for moderate-to-severe disease.

Funding: Funding was provided by the Centers for Disease Control and Prevention though contract 75D30120C07986 to Westat, Inc. and contract 75D30120C07765 to Kaiser Foundation Hospitals.

Keywords: Boosters; COVID-19; Hospitalization; Number needed to vaccinate; mRNA vaccines.