"Disease X is a name for a disease whose details are as yet unknown"

"This vaccine research and creation is said to be taking place at Porton Down laboratory"

https://web.archive.org/web/20240128151001/https://www.msn.com/en-us/health/other/medical-experts-developing-vaccine-for-disease-x-which-could-be-20-times-more-infectious-than-covid/ar-AA1n0F9C