I'm not so sure it is that popular on HN. I don't remember seeing any articles all that often before recently with the outbreak in Canada. I'll see the topic pop up far more often on Reddit, but it's still fairly rare. I think people are interested because it is such a terrifying thing that we don't have any good solutions for. So it inspires discussions whenever somebody reminds everybody else "so, hey, this is still a thing" and it makes its rounds.