Effectiveness of Influenza Vaccine for Preventing Laboratory-Confirmed Influenza Hospitalizations in Immunocompromised Adults
Authors: Hughes Kailey , Middleton Donald B , Nowalk Mary Patricia , Balasubramani Goundappa K , Martin Emily T , Gaglani Manjusha , Talbot H Keipp , Patel Manish M , Ferdinands Jill M , Zimmerman Richard K , Silveira Fernanda P ,   for the HAIVEN Study Investigators, Zimmerman Richard , Middleton Donald , Silveira Fernanda , Hughes Kailey , Eng Heather , Sax Theresa , Saul Sean , Rinaldo Charles , Goundappa Balasubramani , Nowalk Mary Patricia , Steiffel Lori , Williams John , Johnson Monika , Gaglani Manjusha , Murthy Kempapura , McNeal Tresa , Ghamande Shekar , Escobedo Victor , Robertson Anne , Clipper Lydia , Rao Arundhati , Chang Kevin , Volz Marcus , Walker Kimberly , Arroliga Alejandro , Monto Arnold , Martin Emily , Malosh Ryan , Petrie Joshua , Lauring Adam , Cheng Caroline , Segaloff Hannah , McSpadden E J , Johnson Emileigh , Truscon Rachel , Lamerato Lois , Davis Susan , Zervos Marcus , Talbot H Keipp , Wyatt Dayna , Zhu Yuwei , Liu Zhouwen , McHenry Rendie , Halasa Natasha , Calvillo Sandra Alvarez , Longmire Stephanie , Stewart Laura , Ferdinands Jill , Fry Alicia , Alyanak Elif , Smith Emily , Strickland Courtney , Spencer Sarah , Flannery Brendan , Chung Jessie , Xu Xiyan , Lindstrom Stephen , Berman LaShondra , Sessions Wendy , Kondor Rebecca , Patel Manish 
Published: December 2020

Background

Yearly influenza immunization is recommended for immunocompromised (IC) individuals, although immune responses are lower than that for the nonimmunocompromised and the data on vaccine effectiveness (VE) in the IC is scarce. We evaluated VE against influenza-associated hospitalization among IC adults.

Methods

We analyzed data from adults ≥ 18 years hospitalized with acute respiratory illness (ARI) during the 2017–2018 influenza season at 10 hospitals in the United States. IC adults were identified using prespecified case definitions using electronic medical record data. VE was evaluated with a test-negative case-control design using multivariable logistic regression with polymerase chain reaction–confirmed influenza as the outcome and vaccination status as the exposure, adjusting for age, enrolling site, illness onset date, race, days from onset to specimen collection, self-reported health, and self-reported hospitalizations.

Results

Of 3524 adults hospitalized with ARI, 1210 (34.3%) had an immunocompromising condition. IC adults were more likely to be vaccinated than non-IC (69.5% vs 65.2%) and less likely to have influenza (22% vs 27.8%). The mean age did not differ among IC and non-IC (61.4 vs 60.8 years of age). The overall VE against influenza hospitalization, including immunocompetent adults, was 33% (95% confidence interval [CI], 21–44). VE among IC vs non-IC adults was lower at 5% (95% CI, –29% to 31%) vs 41% (95% CI, 27–52) (P &lt; .05 for interaction term).

Conclusions

VE in 1 influenza season was very low among IC individuals. Future efforts should include evaluation of VE among the different immunocompromising conditions and whether enhanced vaccines improve the suboptimal effectiveness among the immunocompromised.