Bibliographic Details
| Title: |
Influenza Vaccine Effectiveness for Prevention of Severe Influenza-Associated Illness Among Adults in the United States, 2019–2020: A Test-Negative Study. |
| Authors: |
Grijalva, Carlos G, Feldstein, Leora R, Talbot, H Keipp, Aboodi, Michael, Baughman, Adrienne H, Brown, Samuel M, Casey, Jonathan D, Erickson, Heidi L, Exline, Matthew C, Files, D Clark, Gibbs, Kevin W, Ginde, Adit A, Gong, Michelle N, Halasa, Natasha, Khan, Akram, Lindsell, Christopher J, Nwosu, Samuel K, Peltan, Ithan D, Prekker, Matthew E, Rice, Todd W |
| Source: |
Clinical Infectious Diseases; 10/15/2021, Vol. 73 Issue 8, p1459-1468, 10p |
| Subject Terms: |
INFLUENZA complications, INFLUENZA prevention, INFLUENZA vaccines, INTENSIVE care units, CAUSES of death, IMMUNIZATION, CONFIDENCE intervals, SEVERITY of illness index, DESCRIPTIVE statistics, HOSPITAL care, LONGITUDINAL method, SARS disease |
| Geographic Terms: |
UNITED States |
| Abstract: |
Background Influenza vaccine effectiveness (VE) against a spectrum of severe disease, including critical illness and death, remains poorly characterized. Methods We conducted a test-negative study in an intensive care unit (ICU) network at 10 US hospitals to evaluate VE for preventing influenza-associated severe acute respiratory infection (SARI) during the 2019–2020 season, which was characterized by circulation of drifted A/H1N1 and B-lineage viruses. Cases were adults hospitalized in the ICU and a targeted number outside the ICU (to capture a spectrum of severity) with laboratory-confirmed, influenza-associated SARI. Test-negative controls were frequency-matched based on hospital, timing of admission, and care location (ICU vs non-ICU). Estimates were adjusted for age, comorbidities, and other confounders. Results Among 638 patients, the median (interquartile) age was 57 (44–68) years; 286 (44.8%) patients were treated in the ICU and 42 (6.6%) died during hospitalization. Forty-five percent of cases and 61% of controls were vaccinated, which resulted in an overall VE of 32% (95% CI: 2–53%), including 28% (−9% to 52%) against influenza A and 52% (13–74%) against influenza B. VE was higher in adults 18–49 years old (62%; 95% CI: 27–81%) than those aged 50–64 years (20%; −48% to 57%) and ≥65 years old (−3%; 95% CI: −97% to 46%) (P = .0789 for interaction). VE was significantly higher against influenza-associated death (80%; 95% CI: 4–96%) than nonfatal influenza illness. Conclusions During a season with drifted viruses, vaccination reduced severe influenza-associated illness among adults by 32%. VE was high among young adults. [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |
