Vaccine Effectiveness Against Influenza A–Associated Hospitalization, Organ Failure, and Death: United States, 2022–2023
Authors: Lewis Nathaniel M , Zhu Yuwei , Peltan Ithan D , Gaglani Manjusha , McNeal Tresa , Ghamande Shekhar , Steingrub Jay S , Shapiro Nathan I , Duggal Abhijit , Bender William S , Taghizadeh Leyla , Brown Samuel M , Hager David N , Gong Michelle N , Mohamed Amira , Exline Matthew C , Khan Akram , Wilson Jennifer G , Qadir Nida , Chang Steven Y , Ginde Adit A , Mohr Nicholas M , Mallow Christopher , Lauring Adam S , Johnson Nicholas J , Gibbs Kevin W , Kwon Jennie H , Columbus Cristie , Gottlieb Robert L , Raver Catherine , Vaughn Ivana A , Ramesh Mayur , Johnson Cassandra , Lamerato Lois , Safdar Basmah , Casey Jonathan D , Rice Todd W , Halasa Natasha , Chappell James D , Grijalva Carlos G , Talbot H Keipp , Baughman Adrienne , Womack Kelsey N , Swan Sydney A , Harker Elizabeth , Price Ashley , DeCuir Jennifer , Surie Diya , Ellington Sascha , Self Wesley H ,   for the Investigating Respiratory Viruses in the Acutely Ill (IVY) Network, Calhoun Nicole , Murthy Kempapura , Cravens Joselyn , Herrick Judy , McKillop Amanda , Hoffman Eric , Graves Ashley , Zayed Martha , Smith Michael , Scott Baylor , Health White , Fisher Tammy , Hurutado-Rodriguez Mariana , Kruse Taryn , Dunkley Symone , Perez Gabriela , Bychkowski Ashley , Grefsrud Therissa , Calhoun Nicole , Murthy Kempapura , Herrick Judy , Smith Michael , Steingrub Jay , Kozikowski Lori-Ann , De Souza Lesley , Ouellette Scott , Shapiro Nathan I , Bolstad Michael , Coviello Brianna , Ciottone Robert , Devilla Arnaldo , Grafals Ana , Higgins Conor , Ottanelli Carlo , Redman Kimberly , Scaffidi Douglas , Weingart Alexander , Surie Diya , McMorrow Meredith , DeCuir Jennifer , Lewis Nathaniel , Harker Elizabeth , Ellington Sascha , Mehkri Omar , Mitchell Megan , Griffith Zachary , Brennan Connery , Ashok Kiran , Poynter Bryan , Duggal Abhijit , Busse Laurence , ten Lohuis Caitlin , Stanley Nicholas , Zhang Sophia , Prekker Matthew E , Frosch Anne E P , Hendrickson Audrey , Douglas Stephen , Hurreh Kowsar , Peltan Ithan , Smith Cassie , Marshall Hunter , Hager David N , Ali Harith , Phan Minh , Gong Michelle , Mohamed Amira , Nair Rahul , Chen Jen-Ting (Tina) , Exline Matthew , Karow Sarah , Khan Maryiam , So Madison , Snyder Connor , Swoope Gabrielle , Smith David , Lee Brooke , Rasul Amanie , Pathak Manisha , Lewald Zachery , Wilson Reece , Khan Akram , Peña José , Briceno Genesis , Ahmed Cassandra , Martinez Jesus , Pocius Edvinas , Oh Minn , Hyde Jessica , Gause Sherie , Wilson Jennifer G , Gordon Alexandra June , Perez Cynthia , Lau Lily , Bekiroglu Ismail Hakki , Tran Cody , Frankel Trevor , Garner Omai , Chandrasekaran Sukantha , Ginde Adit , Douin David , Martinez Amanda , Huynh David , Steinwand Aimee , Sullivan Amy , Withers Cori , Mohr Nicholas , Zepeski Anne , Nassar Paul , Landers Shannon , Nielsen Karin , Briggs Noble , Fairfield Cathy , Peebles Alex , Mallow Chris , Rivas Carolina , Martin Emily , Monto Arnold , Lauring Adam , McSpadden E J , Truscon Rachel , Kaniclides Anne , Thomas Lara , Bielak Ramsay , Valvano Weronika Damek , Fong Rebecca , Fitzsimmons William J , Blair Christopher N , Gilbert Julie , Papalambros Leigh , Holz Ankur , Johnson Nicholas , Srinivasan Vasisht , Crider Christine D , Steinbock Kyle A , Paulsen Thomas C , Anderson Layla A , Self Wesley H , Talbot H Keipp , Grijalva Carlos , Jones Ian , Halasa Natasha , Chappell James , Womack Kelsey , Rhoads Jillian , Baughman Adrienne , Kampe Christy , Johnson Jakea , Swan Sydney , Johnson Cassandra , Zhu Yuwei , Rice Todd , Casey Jonathan , Stubblefield William B , Zhu Yuwei , Short Laura L , Ezzell Lauren J , Whitsett Margaret E , McHenry Rendie E , Hargrave Samarian J , Blair Marcia , Luther Jennifer L , Pulido Claudia Guevara , Peterson Bryan P M , Files D Clark , Gibbs Kevin , Landreth Leigha , Hicks Madeline , Parks Lisa , Kwon Jennie , Parikh Bijal , McDonald David , Samuels Carleigh , Vogt Lucy , O’Neil Caroline , Valencia Alyssa , Hink Tiffany , Bychkowski Ashley , Dunkley Symone , Fisher Tammy , Grefsrud Therissa , Hurutado-Rodriguez Mariana H , Perez Gabriela Cantu , Beney Kim , Jayaprakash Rachna , Koneru Sindhuja , Lava Jean Ashley , Pinderi Zina , Resk Melissa , Goyal Anirudh , DeLamielleure Lauren , Kosover Michael , Brokowski Carolyn 
Published: December 2023

Abstract

Background
Influenza circulation during the 2022–2023 season in the United States largely returned to pre–coronavirus disease 2019 (COVID-19)-pandemic patterns and levels. Influenza A(H3N2) viruses were detected most frequently this season, predominately clade 3C.2a1b.2a, a close antigenic match to the vaccine strain.

Methods
To understand effectiveness of the 2022–2023 influenza vaccine against influenza-associated hospitalization, organ failure, and death, a multicenter sentinel surveillance network in the United States prospectively enrolled adults hospitalized with acute respiratory illness between 1 October 2022, and 28 February 2023. Using the test-negative design, vaccine effectiveness (VE) estimates against influenza-associated hospitalization, organ failures, and death were measured by comparing the odds of current-season influenza vaccination in influenza-positive case-patients and influenza-negative, SARS-CoV-2–negative control-patients.

Results
A total of 3707 patients, including 714 influenza cases (33% vaccinated) and 2993 influenza- and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–negative controls (49% vaccinated) were analyzed. VE against influenza-associated hospitalization was 37% (95% confidence interval [CI]: 27%–46%) and varied by age (18–64 years: 47% [30%–60%]; ≥65 years: 28% [10%–43%]), and virus (A[H3N2]: 29% [6%–46%], A[H1N1]: 47% [23%–64%]). VE against more severe influenza-associated outcomes included: 41% (29%–50%) against influenza with hypoxemia treated with supplemental oxygen; 65% (56%–72%) against influenza with respiratory, cardiovascular, or renal failure treated with organ support; and 66% (40%–81%) against influenza with respiratory failure treated with invasive mechanical ventilation.

Conclusions
During an early 2022–2023 influenza season with a well-matched influenza vaccine, vaccination was associated with reduced risk of influenza-associated hospitalization and organ failure.