Resumen:
METHODS:
Patients with influenza-like illness hospitalized or attended by sentinel general practitioners were swabbed for influenza testing. The previous and current vaccine status of laboratory-confirmed cases was compared to test-negative controls.
RESULTS:
Among 1213 patients tested, 619 (51%) were confirmed for influenza virus: 52% influenza A(H3N2), 46% influenza B, and 2% A(H1N1)pdm09. The overall effectiveness for subunit vaccination in the current season was 19% (95% confidence interval [CI]: -13 to 42), 2% (95%CI: -47 to 35) against influenza A(H3N2) and 32% (95%CI: -4 to 56) against influenza B. The effectiveness against any influenza was 67% (95%CI: 17-87) for 2012-2013 and 2013-2014 vaccination only, 42% (95%CI: -31 to 74) for 2014-2015 vaccination only, and 38% (95%CI: 8-58) for vaccination in the 2012-2013, 2013-2014 and 2014-2015 seasons. The same estimates against influenza A(H3N2) were 47% (95%CI: -60 to 82), -54% (95%CI: -274 to 37) and 28% (95%CI: -17 to 56), and against influenza B were 82% (95%CI: 19-96), 93% (95%CI: 45-99) and 43% (95%CI: 5-66), respectively.
CONCLUSION:
These results suggest a considerable residual protection of split vaccination in previous seasons, low overall effectiveness of current season subunit vaccination, and possible interference between current subunit and previous split vaccines.
