Mpox Surveillance and Laboratory Response: Lessons Learned from Three Outbreak Waves (2022–2025)

Background/Objectives: Mpox re-emerged in 2022 as a global health concern. Between 2022 and 2025, Portugal experienced three distinct outbreak waves, highlighting the criti-cal role of laboratory surveillance and public health interventions. This study describes the epidemiological trends, diagnostic performance, and key lessons learned to improve outbreak preparedness. Methods: A total of 5,610 clinical samples from 2,802 suspected cases were analyzed at the National Institute of Health Doutor Ricardo Jorge using re-al-time PCR methods. Positivity rates and viral loads (Ct values) were assessed across dif-ferent clinical specimen types, including lesion, anal, oropharyngeal swabs, and urine samples. Results: Mpox was confirmed in 1,202 patients. The first outbreak accounted for 79.3% of cases (n=953), followed by a significant reduction in transmission during subse-quent waves. Lesion and rectal swabs provided the highest diagnostic sensitivity (95.1% and 87.9%, respectively). Oropharyngeal swabs contributed to diagnosis in cases without visible lesions, while urine samples showed limited utility. Conclusions: This study un-derscores the importance of sustained laboratory surveillance and adaptive public health strategies in controlling mpox outbreaks. Optimizing specimen collection enhances diag-nostic accuracy, supporting early detection. Continuous monitoring, combined with tar-geted vaccination and effective risk communication, is essential to prevent resurgence and ensure rapid response in non-endemic regions.