Despite the official numbers being low, the WHO has warned the healthcare system in China could be under severe pressure.
Dr Michael Ryan, of the WHO, says: "In China, what's been reported is relatively low numbers of cases in ICUs, but anecdotally ICUs are filling up."
Videos have been emerging on social media appearing to show crowded hospitals.
By cross-referencing with other images posted online, the BBC has been able to verify two videos of overcrowding at a children's hospital in the city of Tianjin in northern China.
