It may be statistically significant improvement but I doubt that most rational, informed patients would consent to an experimental genetic therapy that reduced the likelihood of a flu-like illness by as little as 2.2% within a year.
I would be especially curious to know:
-if this was extrapolated, do the cohorts' infection rates eventually meet
-extrapolating further, would the boosted cohort rate even exceed the control, especially as natural immunity increases more quickly in the control
-the rate and seriousness of vaccine side-effects within the boosted cohort
-the cumulative rate and seriousness of vaccine side-effects with annual boosters
-serious injury and mortality from the vaccine in the boosted group vs serious injury and mortality from the disease in the control group