This year’s flu shot will be missing a strain of influenza it’s protected against for more than a decade.
That’s because there have been no confirmed flu cases caused by the Influenza B/Yamagata lineage since spring 2020. And the Food and Drug Administration decided this year that the strain now poses little to no threat to human health.
Scientists have concluded that widespread physical distancing and masking practiced during the early days of COVID-19 appear to have pushed B/Yamagata into oblivion.
A huge number of viruses have both human and non-human vectors and jump back and forth between us. Many dog owners can tell you about how both they and their dog once got sick at the same time. I doubt it would actually stop as much transmission as you think.