%0 Journal Article
%T Late-Season Influenza Vaccine Effectiveness Against Medically Attended Outpatient Illness, United States, December 2022-April 2023.
%A Chung JR
%A Shirk P
%A Gaglani M
%A Mutnal MB
%A Nowalk MP
%A Moehling Geffel K
%A House SL
%A Curley T
%A Wernli KJ
%A Kiniry EL
%A Martin ET
%A Vaughn IA
%A Murugan V
%A Lim ES
%A Saade E
%A Faryar K
%A Williams OL
%A Walter EB
%A Price AM
%A Barnes JR
%A DaSilva J
%A Kondor R
%A Ellington S
%A Flannery B
%J Influenza Other Respir Viruses
%V 18
%N 6
%D 2024 Jun
%M 38923314
%F 5.606
%R 10.1111/irv.13342
%X <B>BACKGROUND: </B>The 2022-23 US influenza season peaked early in fall 2022.<BR><B>METHODS: </B>Late-season influenza vaccine effectiveness (VE) against outpatient, laboratory-confirmed influenza was calculated among participants of the US Influenza VE Network using a test-negative design.<BR><B>RESULTS: </B>Of 2561 participants enrolled from December 12, 2022 to April 30, 2023, 91 laboratory-confirmed influenza cases primarily had A(H1N1)pdm09 (6B.1A.5a.2a.1) or A(H3N2) (3C.2a1b.2a.2b). Overall, VE was 30% (95% confidence interval -9%, 54%); low late-season activity precluded estimation for most subgroups.<BR><B>CONCLUSIONS: </B>2022-23 late-season outpatient influenza VE was not statistically significant. Genomic characterization may improve the identification of influenza viruses that circulate postinfluenza peak.