tetano
Editor, Senior Moderator
Clin Infect Dis
. 2022 Nov 3;ciac869.
doi: 10.1093/cid/ciac869. Online ahead of print.
Vaccine effectiveness against influenza A(H3N2)-associated hospitalized illness, United States, 2022
Mark W Tenforde[SUP] 1 [/SUP], Manish M Patel[SUP] 2 [/SUP], Nathaniel M Lewis[SUP] 3 [/SUP], Katherine Adams[SUP] 4 [/SUP], Manjusha Gaglani[SUP] 5 [/SUP], Jay S Steingrub[SUP] 6 [/SUP], Nathan I Shapiro[SUP] 7 [/SUP], Abhijit Duggal[SUP] 8 [/SUP], Matthew E Prekker[SUP] 9 [/SUP], Ithan D Peltan[SUP] 10 [/SUP], David N Hager[SUP] 11 [/SUP], Michelle N Gong[SUP] 12 [/SUP], Matthew C Exline[SUP] 13 [/SUP], Adit A Ginde[SUP] 14 [/SUP], Nicholas M Mohr[SUP] 15 [/SUP], Christopher Mallow[SUP] 16 [/SUP], Emily T Martin[SUP] 17 [/SUP], H Keipp Talbot[SUP] 18 [/SUP], Kevin W Gibbs[SUP] 19 [/SUP], Jennie H Kwon[SUP] 20 [/SUP], James D Chappell[SUP] 21 [/SUP], Natasha Halasa[SUP] 22 [/SUP], Adam S Lauring[SUP] 23 [/SUP], Christopher J Lindsell[SUP] 24 [/SUP], Sydney A Swan[SUP] 25 [/SUP], Kimberly W Hart[SUP] 26 [/SUP], Kelsey N Womack[SUP] 27 [/SUP], Adrienne Baughman[SUP] 28 [/SUP], Carlos G Grijalva[SUP] 29 [/SUP], Wesley H Self[SUP] 30 [/SUP], Influenza and Other Viruses in the Acutely Ill Network
Affiliations
Abstract
Background: The COVID-19 pandemic was associated with historically low influenza circulation during the 2020-2021 season, followed by increase in influenza circulation during the 2021-2022 US season. The 2a.2 subgroup of the influenza A(H3N2) 3C.2a1b subclade that predominated was antigenically different from the vaccine strain.
Methods: To understand the effectiveness of the 2021-2022 vaccine against hospitalized influenza illness, a multi-state sentinel surveillance network enrolled adults aged ≥18 years hospitalized with acute respiratory illness (ARI) and tested for influenza by a molecular assay. Using the test-negative design, vaccine effectiveness (VE) was measured by comparing the odds of current season influenza vaccination in influenza-positive case-patients and influenza-negative, SARS-CoV-2-negative controls, adjusting for confounders. A separate analysis was performed to illustrate bias introduced by including SARS-CoV-2 positive controls.
Results: A total of 2334 patients, including 295 influenza cases (47% vaccinated), 1175 influenza- and SARS-CoV-2 negative controls (53% vaccinated), and 864 influenza-negative and SARS-CoV-2 positive controls (49% vaccinated), were analyzed. Influenza VE was 26% (95%CI: -14 to 52%) among adults aged 18-64 years, -3% (95%CI: -54 to 31%) among adults aged ≥65 years, and 50% (95%CI: 15 to 71%) among adults 18-64 years without immunocompromising conditions. Estimated VE decreased with inclusion of SARS-CoV-2-positive controls.
Conclusions: During a season where influenza A(H3N2) was antigenically different from the vaccine virus, vaccination was associated with a reduced risk of influenza hospitalization in younger immunocompetent adults. However, vaccination did not provide protection in adults ≥65 years of age. Improvements in vaccines, antivirals, and prevention strategies are warranted.
Keywords: Influenza; SARS-CoV-2; antigenic drift; vaccine effectiveness.
. 2022 Nov 3;ciac869.
doi: 10.1093/cid/ciac869. Online ahead of print.
Vaccine effectiveness against influenza A(H3N2)-associated hospitalized illness, United States, 2022
Mark W Tenforde[SUP] 1 [/SUP], Manish M Patel[SUP] 2 [/SUP], Nathaniel M Lewis[SUP] 3 [/SUP], Katherine Adams[SUP] 4 [/SUP], Manjusha Gaglani[SUP] 5 [/SUP], Jay S Steingrub[SUP] 6 [/SUP], Nathan I Shapiro[SUP] 7 [/SUP], Abhijit Duggal[SUP] 8 [/SUP], Matthew E Prekker[SUP] 9 [/SUP], Ithan D Peltan[SUP] 10 [/SUP], David N Hager[SUP] 11 [/SUP], Michelle N Gong[SUP] 12 [/SUP], Matthew C Exline[SUP] 13 [/SUP], Adit A Ginde[SUP] 14 [/SUP], Nicholas M Mohr[SUP] 15 [/SUP], Christopher Mallow[SUP] 16 [/SUP], Emily T Martin[SUP] 17 [/SUP], H Keipp Talbot[SUP] 18 [/SUP], Kevin W Gibbs[SUP] 19 [/SUP], Jennie H Kwon[SUP] 20 [/SUP], James D Chappell[SUP] 21 [/SUP], Natasha Halasa[SUP] 22 [/SUP], Adam S Lauring[SUP] 23 [/SUP], Christopher J Lindsell[SUP] 24 [/SUP], Sydney A Swan[SUP] 25 [/SUP], Kimberly W Hart[SUP] 26 [/SUP], Kelsey N Womack[SUP] 27 [/SUP], Adrienne Baughman[SUP] 28 [/SUP], Carlos G Grijalva[SUP] 29 [/SUP], Wesley H Self[SUP] 30 [/SUP], Influenza and Other Viruses in the Acutely Ill Network
Affiliations
- PMID: 36327388
- DOI: 10.1093/cid/ciac869
Abstract
Background: The COVID-19 pandemic was associated with historically low influenza circulation during the 2020-2021 season, followed by increase in influenza circulation during the 2021-2022 US season. The 2a.2 subgroup of the influenza A(H3N2) 3C.2a1b subclade that predominated was antigenically different from the vaccine strain.
Methods: To understand the effectiveness of the 2021-2022 vaccine against hospitalized influenza illness, a multi-state sentinel surveillance network enrolled adults aged ≥18 years hospitalized with acute respiratory illness (ARI) and tested for influenza by a molecular assay. Using the test-negative design, vaccine effectiveness (VE) was measured by comparing the odds of current season influenza vaccination in influenza-positive case-patients and influenza-negative, SARS-CoV-2-negative controls, adjusting for confounders. A separate analysis was performed to illustrate bias introduced by including SARS-CoV-2 positive controls.
Results: A total of 2334 patients, including 295 influenza cases (47% vaccinated), 1175 influenza- and SARS-CoV-2 negative controls (53% vaccinated), and 864 influenza-negative and SARS-CoV-2 positive controls (49% vaccinated), were analyzed. Influenza VE was 26% (95%CI: -14 to 52%) among adults aged 18-64 years, -3% (95%CI: -54 to 31%) among adults aged ≥65 years, and 50% (95%CI: 15 to 71%) among adults 18-64 years without immunocompromising conditions. Estimated VE decreased with inclusion of SARS-CoV-2-positive controls.
Conclusions: During a season where influenza A(H3N2) was antigenically different from the vaccine virus, vaccination was associated with a reduced risk of influenza hospitalization in younger immunocompetent adults. However, vaccination did not provide protection in adults ≥65 years of age. Improvements in vaccines, antivirals, and prevention strategies are warranted.
Keywords: Influenza; SARS-CoV-2; antigenic drift; vaccine effectiveness.