NYMC Faculty Publications

Title

Effectiveness of Influenza Vaccine in Preventing Medically-Attended Influenza Virus Infection in Primary Care, Israel, Influenza Seasons 2014/15 and 2015/16

Document Type

Article

Publication Date

February 2018

Department

Family and Community Medicine

Abstract

IntroductionInfluenza vaccine is recommended for the entire population in Israel. We assessed influenza vaccine effectiveness (VE) for the 2014/15 and 2015/16 seasons in Israel, for the first time. Methods: Combined nose and throat swab specimens were collected from patients with influenza-like illness (ILI) presenting to sentinel primary care clinics and tested for influenza virus by RT-PCR. VE of the trivalent inactivated vaccine (TIV) was assessed using test-negative case-control design. Results: During the 2014/15 season 1,142 samples were collected; 327 (28.6%) were positive for influenza, 83.8% A(H3N2), 5.8% A(H1N1)pdm09, 9.2% B and 1.2% A un-subtyped. Adjusted VE against all influenza viruses for this influenza season was -4.8% (95% confidence interval (CI): -54.8 to 29.0) and against influenza A(H3N2), it was -15.8% (95% CI: -72.8 to 22.4). For the 2015/16 season, 1,919 samples were collected; 853 (44.4%) were positive for influenza, 43.5% A(H1N1)pdm09, 57% B, 0.7% A(H3N2) and 11 samples positive for both A(H1N1)pdm09 and B. Adjusted VE against all influenza viruses for this influenza season was 8.8% (95% CI: -25.1 to 33.5), against influenza A(H1N1)pdm09, it was 32.3% (95% CI: (-4.3 to 56.1) and against influenza B, it was -2.2% (95% CI: (-47.0 to 29.0). Conclusions: Using samples from patients with ILI visiting sentinel clinics in Israel, we demonstrated the feasibility of influenza VE estimation in Israel.

Share

COinS