Live attenuated flu vaccine not effective for children in 2015-16
Michael L. Jackson, Ph.D., from the Group Health Research Institute in Seattle, and colleagues enrolled patients age 6 months of age or older who presented with acute respiratory illness at ambulatory care clinics. Vaccine effectiveness was estimated using a test-negative design.
The researchers found that 19 percent of the 6,879 eligible participants tested positive for influenza virus, predominantly for A(H1N1)pdm09 and influenza B (11 and 7 percent, respectively). The effectiveness of the influenza vaccine was 48 percent against any influenza illness (95 percent confidence interval [CI], 41 to 55 percent; P < 0.001). The inactivated influenza vaccine was 60 percent effective among children age 2 to 17 years (95 percent CI, 47 to 70 percent; P < 0.001), while the live attenuated vaccine was not effective (vaccine effectiveness, 5 percent; 95 percent CI, −47 to 39 percent; P = 0.80). Among children, vaccine effectiveness against A(H1N1)pdm09 was 63 percent for the inactivated vaccine (95 percent CI, 45 to 75 percent; P < 0.001), compared with −19 percent for the live attenuated vaccine (95 percent CI, −113 to 33; P = 0.55).
"Influenza vaccines reduced the risk of influenza illness in 2015 to 2016," the authors write. "However, the live attenuated vaccine was found to be ineffective among children in a year with substantial inactivated vaccine effectiveness."
Copyright © 2017 HealthDay. All rights reserved.