[TheCapn]

>However, it does not explain why we haven't heard of flu outbreaks in cruises before this coronavirus.

Anecdotally I hear about it almost every time the topic of cruises come up on Reddit or other social media. I just don't think its particularly newsworthy so it isn't making headlines. Cruise ships and Conventions are pretty similar in the sense that people just get notoriously sick after attending is my understanding.