Disease X is a term used to describe an illness caused by a presently unknown, yet serious microbial threat. The World Health Organization (WHO) added Disease X in 2017 to a short list of pathogens deemed a top priority for research, alongside known killers like Severe Acute Respiratory Syndrome (SARS) and Ebola. The idea behind studying Disease X is to encourage the development of platform technologies, including vaccines, drug therapies, and diagnostic tests, that could be rapidly adapted and deployed in response to an array of future outbreaks with epidemic or pandemic potential. The vast reservoir of viruses circulating in wildlife is seen as a likely source of more such diseases, as they have the potential to spill over and infect other species, including humans, giving rise to an infection against which people will have no immunity. The Disease X Act of 2023 was established to protect Americans by establishing a Disease X Medical Countermeasures Program at the Biomedical Advanced Research and Development Authority (BARDA) in HHS. The act aims to promote the development of Disease X medical countermeasures for viral families with pandemic potential. The next pandemic could take 50 million lives, and it might already be on its way, according to Dame Kate Bingham, who chaired the UKs Vaccine Taskforce. Disease X could be 20 times deadlier than Coronavirus. Healthcare experts have issued a caution that this new virus can be as devastating as the Spanish Flu. Disease X refers to a pathogen, known or potentially unknown, that can cause a large-scale, serious pandemic leading to mass-scale human disease.