Abstract
BACKGROUND
Patients
with cancer are at increased risk of developing complications of
influenza. In this study, the authors assessed the effectiveness of
influenza vaccination among cancer patients.
METHODS
A
prospective, non interventional cohort study was conducted during the
2010 to 2011 influenza season. The cohort included adult cancer patients
with solid malignancies who were receiving chemotherapy and hematologic
patients who had active disease. Patients who died between October and
November 2010 (N = 43) were excluded. A comparison was made between
patients who received the 2011 seasonal influenza vaccine with those who
did not. The primary outcome was a composite of hospitalizations for
fever or acute respiratory infections, pneumonia, and/or
infection-related chemotherapy interruptions. All-cause mortality was a
secondary outcome. A propensity-matched analysis was conducted based on
the propensity for vaccination.
RESULTS
Of
806 patients who were included, 387 (48%) were vaccinated. Factors that
were associated independently with vaccination included past influenza
vaccination, past pneumococcal vaccination, >6 months since cancer
diagnosis, country of birth, and cancer type/status. The primary outcome
occurred in 111 of 387 (28.7%) vaccinated patients versus 112 of 419
(26.7%) unvaccinated patients (P = .54). No association was
observed between vaccination and the primary outcome in a
propensity-matched analysis (N = 436) or during peak influenza activity.
The mortality rate was 11.9% (46 of 387 patients) in vaccinated
patients versus 19.1% (80 of 419 patients) in unvaccinated patients (P
= .005). Vaccination retained a significant association with mortality
on multivariable analysis (odds ratio, 2.31; 95% confidence interval,
1.4-3.79) and in a propensity-matched analysis (odds ratio, 2.39; 95%
confidence interval, 1.32-4.32).
4
days; 
