It costs about $20 to get it from my local pharmacy. There are about five million people.

Let's assume that the government/pharmac/healthnz/whomever could source five million doses at a good rate and fund the staffing requirements to administer them. Say that is the same $20/dose cost.

$100m or about ten metres of motorway.

The best part is you don't need to do all five million, I think about 80% is enough for herd immunity to take effect. So it's cheaper at $80m.

'flu takes about a week to recover from. So every person that gets it 'costs' their employer a week's wages. Call that $25/hr × 40hr = $1000/wk. We'd only need to stop 80,000 people from getting 'flu each year to break even. NZ had almost half a million cases in 2025.