1. Emerging and Re-emerging Diseases: New diseases and the resurgence of old ones pose significant challenges. For example, the emergence of COVID-19 required rapid and coordinated global response. 2. Antibiotic Resistance: The misuse of antibiotics has led to the development of resistant strains of bacteria, complicating treatment efforts. 3. Globalization: Increased travel and trade facilitate the rapid spread of diseases across borders. 4. Vaccine Hesitancy: Reluctance or refusal to vaccinate can lead to outbreaks of preventable diseases. 5. Health Disparities: Inequities in healthcare access and quality can hinder disease control efforts, particularly in low- and middle-income countries.
