Thanks for your reply Erin.
I think you're correct about people's generally shorter attention spans nowadays concerning many issues which I was basically thinking the other day soon after my last post in this thread. I don't necessarily believe that most people are inherently more selfish or indifferent in general nowadays, even though it can often seem that way; it's largely symptomatic of the plethora of 24/7 rolling news channels, social media and being forever bombarded with an endless flurry of adverts whenever we go online (including this very site).
I've said this before that prior to the advent of 24/7 rolling news channels and the like (especially pre-2000), people actually watched and listened to news bulletins on the TV and radio at set times throughout the day as there was very little choice back then, plus people actually went out and purchased conventional printed newspapers or had them delivered via subscription to their local newsagents, so were basically more invested in many current affairs for much longer, unlike now where many events (especially not-so-good events) that a lot of us simply tut about and highly condemn in the heat of the moment that then seem to be forgotten about and 'water under the bridge' a couple of days later.
I've noticed over the past 20-odd years or so (on both sides of the Atlantic) many of us have seemingly become more cynical about things in general and less trusting of officialdom and 'experts', even the vast majority who aren't reputed to be unscrupulous. Climate change deniers are among my biggest bugbears ATM, including those who do acknowledge it deep down but act all defeatist with stuff like 'well the planet's now already well damaged beyond repair so what's the point in doing anything, plus why should I be denied the right to 'live and let live' at my age' and 'Well what about the Chinese who are evermore indifferent to all things global warming, so what's the point in the rest of the world taking action?' Yeah right, just because one country (e.g, China) doesn't appear to be taking climate change seriously doesn't mean the rest of the world should simply sit on its laurels and come out with the same old feeble excuse 'it's all a waste of time and money, and a violation of personal freedoms' and inadvertently not give a damn about the generations to come and bury their heads in the sand forever more.
As for issues like teen pregnancies and conventional cigarette smoking; they've generally become less prevalent here in the UK too over recent years despite the fact that many doom-mongers still refuse point blank to believe it (the so-called officialdom cynics) and are still adamant otherwise, despite the official stats here revealing the downward trends similar to those Stateside. Ditto for AIDS/HIV.
So far the current Zika epidemic in Brazil that you mentioned still has yet to be plastered all over the UK media, so here's hoping it doesn't escalate into yet another Covid-like global pandemic; but at least the previous 'epidemic' around the mid 2010s didn't quite materialise in such a manner.