The first announcement from the Chinese government came on 30 December 2019, one day before the events described in your second article. ProMED-Mail sent out an alert on 30 December 2019,[1] and the next day, the outbreak was even reported on CCTV.[2] Social media posts gave additional information, but the existence of an outbreak of likely viral pneumonia was publicly declared before those posts, and people who follow emerging infectious diseases were following the story.
1. https://promedmail.org/promed-post/?id=6864153
2. https://www.reuters.com/article/us-china-health-pneumonia-id...