A 2014 study used epidemiological data to show egg - based mutations are associated with
low vaccine effectiveness in human populations.
Not exact matches
However, even in previous years when the
vaccine has been well - matched to circulating influenza strains,
effectiveness has been
low (40 to 60 percent).
However, when the
vaccines»
effectiveness was examined in different age groups, they were shown to be less effective in adults over 18 years than in children, and
effectiveness was
lowest in adults over 50 years of age.
«That there was differential protection in this context both underlines the potential importance of even
low - virulence or less transmissible strains to older populations and the fact that
vaccines may afford relevant
effectiveness among frail older persons even when A / H1N1 predominates,» the authors wrote.
Vaccinating older individuals is problematic, as the
effectiveness of most
vaccines decrease with age, with maximal responses often as
low as 30 % in the over 70s.5 Nevertheless, vaccination programmes demonstrate the ability to reduce disease burden in the elderly as well as offering a tool to observe immune responses in vivo in humans.
But it's not very reassuring, especially given what we know about vaccination risks and side effects and the very
low effectiveness of flu
vaccines.
Early indications are showing the
effectiveness of this year's flu
vaccine may be
lower.