Answer:
The statements are similar because both imply that the impacts of corona on people who have a certain characteristic will be mild. However, they are different because the first one has two categories of people -- one, the healthy, and the other, the young -- whereas the second one has a single category of people -- the young and healthy. The message probably got "warped" over time because information doesn't spread 100% word-for-word from person to person. Like a game of Telephone, the message gets distorted. What the experts say may not be what some random person hears.
In addition, because the second sentence combined the categories of young and healthy people into one, young people (who are also typically healthy) may have felt more confident about their "resistance" to corona.