The actual data does not show zero cases, but it does show an incredible decline in flu infections this year.

There will always be a small number of people wearing masks incorrectly but that doesn’t invalidate everyone that does. And it’s not just masks etc, it’s also the lengthy lockdown, working from home instead of commuting on public transit, etc etc. It does seem strange that a hospital would report absolutely zero but we have no idea of the context. Maybe the OP lives in a sparsely populated area.