Public health -the public's responsibility?

I've mentioned before how it seems that individuals are losing their responsibility and nowadays it is up to companies and governments to help/tell people how to live their lives responsibly. In a health context this is more extreme: if a person wants to be fat and eat junk food and not do exercise it is surely up to them. They need to make informed choices, for sure; once a government (or a company) has made the relevant information available, why should they still be involved?

Well, moving past this kind of health topic to ones of public health, like SARS or avian flu or HIV/AIDs, one can see that increasingly companies are having to play a much greater role; in a supporting role to gvernments to help governments deal with these kinds of crisese. Why? Because they will be affected -as with any CSR issue- they will start to be impacted through a lack of employees, customers etc. But where is the impact? This involvement is purely a risk management investment. But how many investments must companeis make in risk management? What companies can afford these investments and should they be bearing these costs, probably disproportionately?