*nod* "Not necesarily." It's more to do with how very contageous flu is, especailly in social settings (I assume you're aware that some viruses are more contageous than others, having to do with not only method of contageon - saliva vs. blood for instance, but also with how many virus particules are in each ml of said fluid) and so vaccinating the school children is very good at protecting the vaccinated children (and incidentally their direct care-givers) but confers little herd immunity because of the non-vaccinated ones getting coughed on in shops, on the bus, at home, etc.

But I've only researched it briefly, myself. We decided to get the H5N1 vaccination last year for the (minimal) herd immunity factor, because the higher mortality rate seemed to warrant doing "anything we could". So far we haven't had the regular annual flu shot (it is available / recommended for everyone in this part of Canada) but I might start getting mine because of going to visit my father in the nursing home.