McMaster University
A study led by
McMaster University researchers has found that, contrary to recent reports, flu
nasal sprays provide similar protection against influenza as standard flu
shots.
Published in the
scientific journal Annals of Internal Medicine, the study shows
that the nose spray had a similar effect to the standard flu shot.
Previous
recommendations from the Centers for Disease Control's Advisory Committee on
Immunization Practices (ACIP) had previously called for nasal sprays, or live
attenuated influenza vaccine (LAIV), not be used during the 2016-2017 flu
season.
Dr. Mark Loeb, lead author of the study, says his team's findings
challenge the ACIP's recommendations towards flu shots, or inactivated
vaccines.
"Our results are
important because in previous years the live vaccine had first been preferred
for children. In fact, as late as June 2014, the live vaccine was preferred.
Then, subsequently, it was no longer preferred and now not recommended at all.
Our trial showed no difference between the two in protecting entire
communities."
For the study, Loeb's
team conducted a three-year trial in a Hutterite colony, where people live
communally and are relatively isolated from cities and towns, to determine
whether vaccinating children and adolescents with the flu nasal spray provided
better direct and community protection than the standard flu shot.
The researchers
randomly assigned 1,186 children in 52 Hutterite colonies in Alberta and
Saskatchewan, Canada to receive either the nasal spray vaccine or the flu shot
and also followed 3,425 community members who did not receive a flu vaccine.
Average vaccine coverage among children in the nasal spray group was 76.9 per
cent versus 72.3 per cent in the flu shot group.
The original intention
of the study was to show that nasal spray vaccines would provide better
protection than flu shots, but Loeb says the conclusions of the study are now
especially important, given the ACIP's recommendations.
"The ACIP's
decision was an unprecedented decision in influenza vaccine policy-making for
children. Our study challenges previous studies because our results show
conclusively that the vaccines show similar protection when both direct and
indirect effects are taken into account."
Loeb says his team
will continue to study herd immunity with different vaccine formulations by
vaccinating children. They are also looking at the effect of repeated
vaccination of children.
This study was funded
by the Canadian Institutes for Health Research.
