The cynics will be busy trying to get clicks and views by inventing reasons the NHI isn't real. Some will think it's holographic and fake.
The average person won't care, or at least won't change their daily lives or routines. Until it affects them personally, they'll just keep carrying on.
Honestly, believers will probably do the same. I categorize myself as want-to-believe-and-am-99%-there. I will probably spend several days glued to social media, news, any source where I can learn as much as possible and chat with others. But I'll still need to make my mortgage payment, so unless the NHI says something that changes our society, I am not sure my own daily life would change much. And that's depressing.