Taiwan is not a WHO member, because of objections from China, which claims the island as its own and deems it to have no right to membership of international bodies. On 31/12/19 Taiwan send a email to WHO for more information about a outbreak of a possible new disease in Wuhan, but did not get an answer.
Such an approach, Taiwan says, deprived it of timely information to fight the virus, and it accused the WHO of having ignored its communications early in the pandemic.
The relationship between the WHO, China & Taiwan are visible weird, as proven in the video below. An very strange intervieuw with Dr Bruce Aylward, Senior Advisor to the WHO Director-General.
sources: https://www.heidi.news/sante/coronavirus-le-torchon-brule-entre-taiwan-soutenue-par-les-etats-unis-et-l-oms & https://www.reuters.com/article/us-health-coronavirus-taiwan/taiwan-who-spar-again-over-coronavirus-information-sharing-idUSKCN21T0BA & https://www.who.int/dg/who-headquarters-leadership-team