COVID-19 Incidence and Death Rates Among Unvaccinated and Fully Vaccinated Adults with and Without Booster Doses During Periods of Delta and Omicron Variant Emergence — 25 U.S. Jurisdictions, April 4–December 25, 2021
Amelia G. Johnson, Avnika B. Amin, Akilah R. Ali, Brooke Hoots, Betsy L. Cadwell, Shivani Arora, Tigran Avoundjian, Abiola O. Awofeso, J Ben Barnes, Nagla S. Bayoumi, Katherine Busen, Carolyn Chang, Mike Cima, Molly J. Crockett, Alicia Cronquist, Sherri Davidson, Elizabeth L. Davis, Janelle Delgadillo, Vajeera Dorabawila, Cherie Drenzek, Leah Eisenstein, Hannah E. Fast, Ashley Gent, Julie Hand, Dina Hoefer, Corinne Holtzman, Amanda Jara, Amanda Jones, Ishrat Kamal-Ahmed, Sarah Kangas, FNU Kanishka, Ramandeep Kaur, Saadiah I. Khan, Justice King, Samantha Kirkendall, Anna Klioueva, Anna Kocharian, Frances Y. Kwon, Jacqueline Logan, B. Casey Lyons, Shelby Lyons, Andrea May, Donald B. McCormick, MSHI, Erica Mendoza, Lauren Milroy, Allison N. O’Donnell, Melissa Pike, Sargis Pogosjans, Amy Saupe, Jessica Sell, Elizabeth Smith, Daniel M. Sosin, Emma Stanislawski, Molly Steele, Meagan Stephenson, Allen W. Stout, Kyle Strand, Buddhi Tilakaratne, Kathryn Turner, Hailey Vest, Sydni Warner, Caleb Wiedeman, Allison Zaldivar, Benjamin J. Silk, Heather M. Scobie
Abstract
A COVID-19 case in a fully vaccinated person occurred when SARS-CoV-2 RNA or antigen was detected in a respiratory specimen collected 14 days after completing the primary series of a COVID-19 vaccine with Food and Drug Administration (FDA) approval or emergency use authorization. The COVID-19 case definition, including criteria to distinguish a new case from an existing case, is per the July 2021 update to the national standardized surveillance case definition and national notification for 2019 novel coronavirus disease (COVID-19) (21-ID-01) (https://ndc.services.cdc.gov/case-definitions/ coronavirus-disease-2019-2021/). Fully vaccinated persons were those with a completed primary series of 2 doses of the Pfizer-BioNTech or Moderna mRNA vaccine or a single dose of the Janssen vaccine (https://www.cdc.gov/ coronavirus/2019-ncov/vaccines/stay-up-to-date.html). A COVID-19 case in an unvaccinated person occurred when the person did not receive any FDAauthorized COVID-19 vaccine doses before the specimen collection date. Cases were excluded in partially vaccinated persons who received at least one FDAauthorized or approved vaccine dose but did not complete a primary series 14 days before collection of a respiratory specimen with SARS-CoV-2 RNA or antigen detected. Ascertaining vaccination status for COVID-19 patients through active linkage of case surveillance and immunization information systems typically assumes that cases among persons who are unmatched to the registry are unvaccinated. This analysis represents the combined impact of the Pfizer-BioNTech, Moderna, and Janssen COVID-19 vaccines, which had different clinical efficacies against confirmed infection. Information on different FDA-authorized and approved COVID-19 vaccine products, including clinical efficacy, is available online. https://www.cdc.gov/coronavirus/2019-ncov/ vaccines/different-vaccines.html