tetano
Editor, Senior Moderator
Clin Infect Dis
. 2022 Dec 12;ciac941.
doi: 10.1093/cid/ciac941. Online ahead of print.
Influenza Vaccine Effectiveness Against Influenza A(H3N2)-Related Illness in the United States During the 2021-2022 Influenza Season
Ashley M Price[SUP] 1 [/SUP], Brendan Flannery[SUP] 1 [/SUP], H Keipp Talbot[SUP] 2 [/SUP], Carlos G Grijalva[SUP] 2 [/SUP], Karen J Wernli[SUP] 3 [/SUP], C Hallie Phillips[SUP] 3 [/SUP], Arnold S Monto[SUP] 4 [/SUP], Emily T Martin[SUP] 4 [/SUP], Edward A Belongia[SUP] 5 [/SUP], Huong Q McLean[SUP] 5 [/SUP], Manjusha Gaglani[SUP] 6 7 [/SUP], Manohar Mutnal[SUP] 6 7 [/SUP], Krissy Moehling Geffel[SUP] 8 [/SUP], Mary Patricia Nowalk[SUP] 8 [/SUP], Sara Y Tartof[SUP] 9 [/SUP], Ana Florea[SUP] 9 [/SUP], Callie McLean[SUP] 1 [/SUP], Sara S Kim[SUP] 1 [/SUP], Manish M Patel[SUP] 1 [/SUP], Jessie R Chung[SUP] 1 [/SUP]
Affiliations
Abstract
Background: In the United States, influenza activity during the 2021-2022 season was modest and sufficient enough to estimate influenza vaccine effectiveness for the first time since the beginning of the COVID-19 pandemic. We estimated influenza vaccine effectiveness against lab-confirmed outpatient acute illness caused by predominant A(H3N2) viruses.
Methods: Between October 2021 and April 2022, research staff across 7 sites enrolled patients aged ≥6 months seeking outpatient care for acute respiratory illness with cough. Using a test-negative design, we assessed VE against influenza A(H3N2). Due to strong correlation between influenza and SARS-CoV-2 vaccination, participants who tested positive for SARS-CoV-2 were excluded from vaccine effectiveness estimations. Estimates were adjusted for site, age, month of illness, race/ethnicity and general health status.
Results: Among 6,260 participants, 468 (7%) tested positive for influenza only, including 440 (94%) for A(H3N2). All 206 sequenced A(H3N2) viruses were characterized as belonging to genetic group 3C.2a1b subclade 2a.2, which has antigenic differences from the 2021-2022 season A(H3N2) vaccine component that belongs to clade 3C.2a1b subclade 2a.1. After excluding 1,948 SARS-CoV-2 positive patients, 4,312 patients were included in analyses of influenza VE; 2,463 (57%) were vaccinated against influenza. Effectiveness against A(H3N2) for all ages was 36% (95%CI, 20-49%) overall.
Conclusion: Influenza vaccination in 2021-2022 provided protection against influenza A(H3N2)-related outpatient visits among young persons.
Keywords: case control; influenza; test-negative; vaccination.
. 2022 Dec 12;ciac941.
doi: 10.1093/cid/ciac941. Online ahead of print.
Influenza Vaccine Effectiveness Against Influenza A(H3N2)-Related Illness in the United States During the 2021-2022 Influenza Season
Ashley M Price[SUP] 1 [/SUP], Brendan Flannery[SUP] 1 [/SUP], H Keipp Talbot[SUP] 2 [/SUP], Carlos G Grijalva[SUP] 2 [/SUP], Karen J Wernli[SUP] 3 [/SUP], C Hallie Phillips[SUP] 3 [/SUP], Arnold S Monto[SUP] 4 [/SUP], Emily T Martin[SUP] 4 [/SUP], Edward A Belongia[SUP] 5 [/SUP], Huong Q McLean[SUP] 5 [/SUP], Manjusha Gaglani[SUP] 6 7 [/SUP], Manohar Mutnal[SUP] 6 7 [/SUP], Krissy Moehling Geffel[SUP] 8 [/SUP], Mary Patricia Nowalk[SUP] 8 [/SUP], Sara Y Tartof[SUP] 9 [/SUP], Ana Florea[SUP] 9 [/SUP], Callie McLean[SUP] 1 [/SUP], Sara S Kim[SUP] 1 [/SUP], Manish M Patel[SUP] 1 [/SUP], Jessie R Chung[SUP] 1 [/SUP]
Affiliations
- PMID: 36504336
- DOI: 10.1093/cid/ciac941
Abstract
Background: In the United States, influenza activity during the 2021-2022 season was modest and sufficient enough to estimate influenza vaccine effectiveness for the first time since the beginning of the COVID-19 pandemic. We estimated influenza vaccine effectiveness against lab-confirmed outpatient acute illness caused by predominant A(H3N2) viruses.
Methods: Between October 2021 and April 2022, research staff across 7 sites enrolled patients aged ≥6 months seeking outpatient care for acute respiratory illness with cough. Using a test-negative design, we assessed VE against influenza A(H3N2). Due to strong correlation between influenza and SARS-CoV-2 vaccination, participants who tested positive for SARS-CoV-2 were excluded from vaccine effectiveness estimations. Estimates were adjusted for site, age, month of illness, race/ethnicity and general health status.
Results: Among 6,260 participants, 468 (7%) tested positive for influenza only, including 440 (94%) for A(H3N2). All 206 sequenced A(H3N2) viruses were characterized as belonging to genetic group 3C.2a1b subclade 2a.2, which has antigenic differences from the 2021-2022 season A(H3N2) vaccine component that belongs to clade 3C.2a1b subclade 2a.1. After excluding 1,948 SARS-CoV-2 positive patients, 4,312 patients were included in analyses of influenza VE; 2,463 (57%) were vaccinated against influenza. Effectiveness against A(H3N2) for all ages was 36% (95%CI, 20-49%) overall.
Conclusion: Influenza vaccination in 2021-2022 provided protection against influenza A(H3N2)-related outpatient visits among young persons.
Keywords: case control; influenza; test-negative; vaccination.