MERS-CoV Epidemiology and Global Impact
As of August 5, 2025, the European Centre for Disease Prevention and Control (ECDC) has documented 2,639 confirmed cases of MERS-CoV and 957 associated deaths worldwide since 2012, corresponding to a case fatality rate of ~36%. According to the World Health Organization’s Eastern Mediterranean Regional Office (WHO EMRO), by July 2025 there were 2,627 cases and 947 deaths reported globally. The vast majority of infections have occurred in Saudi Arabia, mainly associated with dromedary camel contact and healthcare-related transmission. Between March 1 and April 21, 2025, Saudi Arabia identified nine new cases, highlighting the virus’s ongoing potential for sporadic outbreaks and hospital clusters.
Fig. 1 from Peeri et al. 2020 - Spatial distribution of MERS-CoV, SARS, and COVID-19, showing global epidemiology and comparisons.
MERS-CoV Structure and Receptor Recognition
MERS-CoV, a Betacoronavirus, features a spike (S) protein composed of S1 (containing the receptor-binding domain, RBD) and S2 subunits, binding to the DPP4/CD26 receptor to mediate host cell entry and membrane fusion. A 2025 Nature study reports that MRCoV (a mink coronavirus within the Merbecovirus genus) can utilize the ACE2 receptor to enter various animal and human cell types, suggesting a potential cross-host transmission risk for Merbecoviruses.
Fig. 2 from Viruses 2019, 11, 60 - Diagram illustrating MERS-CoV genome and structure, highlighting S1 (RBD) and S2 subunits.
| Component |
Description |
Function |
| Spike (S) Protein |
Surface glycoprotein with S1 (RBD) and S2 subunits |
Binds to DPP4 receptor; facilitates membrane fusion and entry |
| Envelope (E) Protein |
Small transmembrane protein |
Involved in viral assembly and release |
| Membrane (M) Protein |
Integral membrane protein |
Shapes the virion envelope; promotes assembly |
| Nucleocapsid (N) Protein |
Binds to RNA genome |
Protects genome; aids in packaging and replication |
| Non-structural Proteins (nsp1-16) |
Encoded by ORF1a/b |
Form replication-transcription complex; modulate host response |
| Accessory Proteins (ORF3,4a,4b,5,8b) |
Virus-specific proteins |
Interfere with host immunity; enhance virulence |
Pathogenesis and Immune Dynamics
MERS-CoV infection can lead to severe pneumonia and acute respiratory distress syndrome (ARDS) due to an exaggerated inflammatory response, often termed a "cytokine storm." Key immune factors include:
| Cytokine/Biomarker |
Role in Pathogenesis |
Interaction/Effects |
| IL-6 |
Triggers cytokine storm and promotes inflammation |
Activates JAK/STAT3 signaling; elevates CRP; contributes to tissue damage |
| TNFα |
Amplifies inflammatory response |
Synergizes with IL-6; damages alveolar and vascular endothelium |
| IFNγ |
Essential for antiviral immunity but excessive worsens pathology |
Overstimulates T-cell responses; enhances cytokine release |
| CRP |
Biomarker of systemic inflammation |
Correlates with disease severity; aids in prognosis |
A 2025 Nature study indicates that a MERS-CoV-like mink coronavirus (MRCoV) uses the ACE2 receptor, pointing to a potential cross-host transmission risk, which may influence pathogenesis dynamics.
Fig. 3 from Peeri et al. 2020 - Infographic comparison of MERS, SARS, and COVID-19, highlighting pathogenesis differences.
References
[1] Wang N. et al. A MERS-CoV-like mink coronavirus uses ACE2 as an entry receptor. Nature. 2025;642:739–746.
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[3] Peeri NC. et al. The SARS, MERS and novel coronavirus (COVID-19) epidemics. Int J Epidemiol. 2020.
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[7] Adney DR, et al. (2019). Efficacy of an adjuvanted MERS-CoV vaccine in dromedary camels. Sci Transl Med, 11(523).
[8] CEPI. (2025). New funding for vaccine to protect against deadly MERS coronavirus. Coalition for Epidemic Preparedness Innovations.
[9] Halfmann PJ, et al. (2025). Merbecovirus S2 subunit vaccines elicit cross-reactive antibodies and provide partial protection against MERS coronavirus. npj Viruses.
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[11] WHO. (2025). MERS-CoV Global Summary and Assessment of Risk. World Health Organization.
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