Lack of effect of seasonal trivalent influenza vaccine against influenza A(H3N2) infections in hospitalised patients in winter 2012

N Z Med J. 2014 Jul 18;127(1398):12-8.


Aim: This study sought to assess the effectiveness of the 2012 trivalent inactivated influenza vaccine in preventing admission with confirmed influenza A(H3N2) infection and whether vaccination status influenced the duration or outcome.

Methods: We used the CDHB Delphic Laboratory Information System to identify 100 consecutive patients with confirmed influenza A(H3N2) infection. The patients were contacted via telephone and asked whether they had received the seasonal influenza vaccine prior to their hospital admission. We collected information such as age, gender, documented co-morbidities, smoking status, ICU admission, length of stay, and final outcome of admission and compared these between the vaccinated and non-vaccinated groups.

Results: A total of 92 participants could be contacted and participated; 67 these reported having been vaccinated with the 2012 seasonal influenza vaccine prior to their admission. There were no significant differences in length of stay or final outcome in vaccinated and non-vaccinated patients.

Conclusion: This audit shows that the 2012 seasonal influenza vaccine did not provide significant protection against the H3N2 influenza strain in Canterbury. Vaccination did not alter the clinical course or final outcome in patients infected with H3N2 influenza.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Comorbidity
  • Female
  • Hospitalization
  • Humans
  • Influenza A Virus, H3N2 Subtype*
  • Influenza, Human / complications
  • Influenza, Human / prevention & control*
  • Influenza, Human / virology
  • Length of Stay*
  • Lung Diseases / complications
  • Male
  • New Zealand