Firstly, the reporting has been overzealous. For example, the article linked says that he had "just learned about the coronavirus after being isolated in the desert for almost two weeks". I don't believe that for a second. This is something that's been with us for more than 12 days, it's not new, it's not something from a zombie movie that lays waste to the world seemingly overnight.
The latest developments - the isolations, the travel bans, the border closures - have all come about very quickly so it is understandable that Leto would be unaware of these and indeed seem to be emerging into a different world.
But changed forever? I'm not so sure.
Once given the all clear will people's behaviour be altered? Will society and governments approach things differently? We live in an age of short-termism where people can't see past their next paycheck and governments the next election. When this is all over will the world return to the excess of before?
I suppose a lot of it depends on how long this all lasts and whether we will get waves of infection after periods of social distancing come to an end. The likes of China and South Korea are looking to get back on their feet now that the risk seems to be reducing but reports that up to 95% of people in certain areas are still susceptible to the virus means that it could all happen again. There have already been small clusters of new infections in South Korea.
What's curious is that the talk of getting back to normal is not consistent. China has, so far, apparently recorded 3241 deaths but in the UK they're saying it will be a good result if deaths are kept below 20,000. That's a massive disparity.
Hopefully we won't get anywhere near that figure and the steps being taken to mitigate and suppress the virus will do their job.