Taylor & Francis
Seasonal influenza is a global public health concern. The World
Health Organization estimates 3-5 million cases of severe infection annually,
resulting in up to half a million deaths.
In industrialized countries, people aged 65 years or older are
most vulnerable, and influenza vaccine is less effective in this age group due
to the age-related weakening of the immune system.
To improve vaccine efficacy in the elderly, a high dose
formulation of the commonly used trivalent inactivated influenza vaccine (IIV)
was tested in a large-scale Phase 3 clinical trial dubbed FIM12.
The high-dose vaccine was shown to be 24% more effective in
preventing influenza in seniors compared to the standard-dose injection.
Using data from the FIM12 trial, a study published in Human Vaccines & Immunotherapeutics now shows that immunizing the elderly population with high-dose vaccine is also cost-saving.
"Total healthcare payer costs, which included vaccine
costs, were about 47 Canadian dollars less per person who received high-dose
IIV," says co-senior author Dr. Ayman Chit of Sanofi Pasteur, Swiftwater,
PA.
When non-prescription drug and productivity costs were added to
the public payer medical costs, savings increased to $60 per vaccine recipient.
The team performed the cost-effectiveness analysis in the
Canadian healthcare context, thereby extending their previous results, which
had shown that high-dose IIV is cost-effective in the U.S. setting as well.
"The original study, FIM12, was a double-blind, randomized,
active-controlled, multi-center trial, conducted during the 2011-12 and 2012-13
influenza seasons in 126 research centers in the United States and
Canada," says Dr. Chit.
"In the efficacy trial, a total of 31,989 adults 65 years
of age and older were randomly assigned in a 1:1 ratio to receive either
high-dose or standard-dose IIV and followed for six to eight months
post-vaccination for the occurrence of influenza, serious adverse events and
medical encounters."
In addition to lower medical expenditures, the high-dose cohort
had slightly higher estimated quality-adjusted life-years, a measure of
survival adjusted for quality of life experienced during that survival. Taken
together, the high-dose IIV provided more health benefit at lower costs.
"As such, these findings are relevant to Canadian
healthcare beneficiaries, providers, payers and recommending bodies, especially
those looking to improve outcomes while containing costs," says Dr. Chit.
These studies show that high-dose IIV could increase health and
quality of life in the elderly.
"The heightened susceptibility of seniors to complications
is due in large part to natural and progressive weakening of the immune system
over time. This phenomenon, known as immunosenescence, renders seniors less
responsive to standard dose influenza vaccine. High-dose IIV, with 60 μg
hemagglutinin per viral strain, was designed to improve efficacy by increasing
vaccine antigen content. It is the only licensed influenza vaccine for seniors
shown in a randomized, head to head, efficacy study to improve clinical
outcomes when compared to the standard-dose vaccine," concludes Dr. Chit.