So, now there's this cheerful news:
Whooping Cough Kills 5 in California; State Declares an Epidemic (NY Times)
Given the demographics, it seems that the problem is a lack of "herd immunity." If a high enough percentage of people in a population are immunized, then it's very unlikely that one sick individual will meet a susceptible individual. This is how you getting your shots protects a newborn infant whose immune system is not yet sufficiently developed to get vaccine. However, given that we have a large migrant population that many voters are opposed to giving any health care, we've significantly increased the odds that any sick individual will meet susceptible, unvaccinated people, including infants.
Whooping Cough really should be extinct. There's a good vaccine (which needs to be retaken every decade--ask your doctor!), and if we could get it to everybody, Pertussis would follow smallpox into oblivion. But, like polio, we (as a species) seem to be unwilling to make the effort save ourselves. As long as these diseases are confined to the far-away or the poor, it's no big deal. However, it has become fashionable in some quarters to not vaccinate one's children (based largely on unsubstantiated fears of autism). When the toddler of some wealthy, trendy suburban family starts making noises like this, something might happen.