I think in this specific case both terms are being used in merged meanings. They are talking about using a national surveillance (as in surveillance state) data collection to help perform public heath surveillance.
What is being proposed from a public health surveillance perspective is reliant on a multifold and invasive surveillance state data collection and mining perspective.
Back in the day, before electronic communications, public health surveillance was just the best surveillance possible. So I believe that it's a largely artificial distinction.
Even so, I agree that there are ways to do public health surveillance where the raw data is buried well enough that users only see actionable information, and only aggregate data is released.
What is being proposed from a public health surveillance perspective is reliant on a multifold and invasive surveillance state data collection and mining perspective.