en تخصصي Special پژوهشي Research <div style="text-align: justify;"><strong>Background</strong>: Mass gatherings pose significant public health challenges due to the potential for infectious disease (ID) transmission. The Arbaeen religious event is among the largest annual gatherings worldwide. Although COVID-19 is less of a global concern, the emergence of new variants and regression in preventive behavior necessitate a risk reassessment particularly for high-density events like the Arbaeen ceremony.<br> <strong>Materials and Methods:</strong> A cross-sectional, expert-based study was conducted in 2025 using the latest version of the WHO COVID-19 mass-gathering risk assessment tool (2022). The participants included 98 experts in epidemiology (EPI), IDs, and disaster and emergency health from Iranian medical universities. The final risk score was derived through consensus and scoring matrices.<br> <strong>Results</strong>: Out of 98 respondents, the mean age was 49 years; average work experience was 19 years. The overall risk level for Arbaeen 2025 was categorized as &ldquo;very high&rdquo; in EPI and health in disaster and emergency (HDE) and &ldquo;medium&rdquo; in IDs. The mean risk evaluation scores were 5.48&plusmn;0.38, 5.73&plusmn;0.22, and 6.37&plusmn;0.36, respectively. Risk mitigation indices showed inadequate preparedness in EPI (22.1&plusmn;3.6) compared with IDs (55.3&plusmn;12.3). The overall risk level across all specialties was estimated as &ldquo;high&rdquo;.&nbsp;<br> <strong>Conclusion</strong>: Arbaeen 2025 poses a substantial risk of COVID-19 resurgence. Despite increased societal tolerance, proactive risk communication, cross-border coordination, and targeted control strategies are urgently needed.</div> COVID-19, Mass gathering, Arbaeen, Risk assessment, Public health preparedness 303 310 http://hdq.uswr.ac.ir/browse.php?a_code=A-10-34-9&slc_lang=en&sid=1 Reza Habibisaravi drhabibisaravi@gmail.com 0000-0003-3279-3693 No Department of Pre-hospital Emergency, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran. Hamidreza Khankeh hrkhankeh@gmail.com 0000-0002-9532-5646 No Department of Emergency and Disaster Health, University of Social Welfare and Rehabilitation Sciences, Tehran, Iran. Seyed Hossein Hosseini Hossein.hosseini389@gmail.com 0000-0001-6630-1023 No Department of Paramedicine, Amol School of Paramedical Sciences, Mazandaran University of Medical Sciences, Sari, Iran. Nahid Aghaei Na.aghaei@gmail.com 0000-0002-1097-3549 No Department of Pre-hospital Emergency, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran. Zoya Hadinejad dr.zoyahadinejad@gmail.com 0009-0005-4593-9577 No Department of Pre-hospital Emergency, School of Allied Medical Sciences, Mazandaran University of Medical Sciences, Sari, Iran. Fariba Ghasemihamedani fghasemihamedani@gmail.com 0000-0002-5904-6017 No Research Center for Emergency and Disaster Resilience, Red Crescent Society of the Islamic Republic of Iran, Tehran, Iran. Mohammad Javad Moradian moradianshiraz@gmail.com Yes Department of Health in Disasters and Emergencies, School of Health Management and Medical Information Sciences, Shiraz University of Medical Sciences, Shiraz, Iran.