Figure 2.

Adjusted vaccine effectiveness against hospitalizations for acute respiratory illness with influenza-associated pneumonia in adults aged ≥18 years: US HAIVEN, 2015–2016 to 2017–2018. Influenza cases were radiographically identified “definite/probable pneumonia” confirmed for influenza by clinical/research single-plex or multiplex RT-PCR. Abbreviations: CI, confidence interval; RT-PCR, reverse transcriptase–polymerase chain reaction; US HAIVEN, US Hospitalized Adult Influenza Vaccine Effectiveness Network; VE, vaccine effectiveness.