When looking at health systems which rely on out-of-pocket spending, equity is usually affected, with co-payments and premiums affecting access by the poorest citizens more so than the richest.  Another example of vertical equity concerns healthcare financing.  Financing the system via income taxes, say, is considered a vertically equitable financing mechanism, as the amount contributed is directly proportionate to a citizen's income.  Sales taxes, on the other hand, would be a larger burden on the poor than the rich, and as such is not vertically equitable.