The concept of Disease X represents a proactive approach to global health preparedness, focusing on the unknown pathogens with pandemic potential. Coined by the World Health Organization (WHO) in 2018, Disease X is a placeholder term for a hypothetical pathogen that could emerge and cause a global health crisis. By addressing this "unknown unknown," health agencies aim to enhance their ability to respond swiftly and effectively to new infectious diseases.

Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security, explains that Disease X serves as a catalyst for forward-thinking in public health. Rather than focusing solely on known threats, it encourages research into broader categories of pathogens, especially those with characteristics conducive to pandemics. For instance, respiratory viruses, which spread easily through coughing, sneezing, and talking, are a prime concern. Additionally, zoonotic viruses—those that jump from animals to humans—or pathogens that evolve new genetic traits are high on the radar.

Disease X preparation involves studying viral families with potential pandemic capabilities, analyzing their transmission modes, and understanding their effects on the human body. This groundwork can accelerate the development of vaccines, treatments, and diagnostics when a new pathogen emerges, as seen during the COVID-19 pandemic. For example, pre-existing research on coronaviruses, prompted by the MERS epidemic, enabled companies like BioNTech and Moderna to design SARS-CoV-2 vaccine candidates within days, significantly speeding up response times.

While the exact origins of the next pandemic are unpredictable, certain regions with high biodiversity and frequent human-animal interactions, such as parts of Asia and Africa, are considered hotspots. However, pandemics can arise anywhere—Mexico's 2009 H1N1 outbreak is a case in point. Enhanced surveillance in areas with increased human-animal contact and biodiversity is critical to identifying potential threats early.

Global preparedness for Disease X is a collective effort involving the WHO, national health agencies like the CDC and the UK Health Security Agency, and organizations such as CEPI (Coalition for Epidemic Preparedness Innovations). Governments, pharmaceutical companies, and local health departments also play crucial roles in creating vaccines, ramping up testing capabilities, and ensuring societal resilience during health crises. Private entities like the World Economic Forum contribute to preparedness by fostering collaboration across sectors.

Despite progress, there are gaps in readiness. While vaccine platforms like mRNA technology have reduced vaccine development times to under a year, challenges remain. Issues such as limited hospital capacity, inconsistent mask production, and public resistance to new medical technologies hinder comprehensive preparedness. The mpox outbreak highlighted these shortcomings, with delays in testing and antiviral access complicating response efforts.

Lessons from COVID-19 emphasize the need for faster vaccine rollouts, incentivized pharmaceutical involvement, and widespread adoption of home testing. Initiatives like Operation Warp Speed exemplify how public-private partnerships can expedite pandemic response. Moreover, CEPI's "100 Days to a Vaccine" goal demonstrates the ambition to shorten timelines even further.

While we are better prepared for pandemics than before COVID-19, significant work remains. Strengthening healthcare systems, fostering public trust in medical interventions, and maintaining vigilance against emerging threats are essential to mitigate the impact of Disease X and protect global health.