The World Health Organization (WHO) has raised alarms about a respiratory virus following a notable increase in cases of Middle East respiratory syndrome coronavirus (MERS-CoV). As of December 21, 2025, the global health agency reported 19 confirmed cases, including four fatalities. Of these, 17 cases were identified in Saudi Arabia, while two were reported in France.
The WHO’s announcement comes in the wake of a broader surge in adenovirus cases worldwide. Health professionals are urging vigilance among both adults and children for potential symptoms associated with respiratory infections. The WHO stated, “Between June 4 and December 21, 2025, the Ministry of Health (MoH) of KSA reported a total of seven cases of MERS-CoV infection, including two deaths.” Although the overall risk assessment for MERS-CoV remains moderate at both global and regional levels, these recent cases highlight the ongoing threat posed by the virus.
MERS-CoV primarily infects dromedary camels, with sporadic transmissions to humans. Currently, there is no vaccine available for the virus, which can lead to severe respiratory symptoms, including fever, coughing, shortness of breath, diarrhea, and vomiting. In severe cases, MERS can be fatal.
New Coronavirus Discovered in Brazil
In a related development, researchers in Brazil have identified a new bat-borne coronavirus, although its impact on human health remains uncertain. The study, conducted by researchers from São Paulo and Ceará, in collaboration with colleagues from Hong Kong University, found this novel coronavirus in an insect-eating bat species. The research, published in the Journal of Medical Virology, revealed that this new virus shares significant genetic similarities with MERS-CoV.
PhD candidate Bruna Stefanie, one of the study’s authors, stated, “Right now we aren’t sure it can infect humans, but we detected parts of the virus’s spike protein, suggesting potential interaction with the receptor used by MERS-CoV.” The researchers analyzed a total of 423 bats from 16 different species, uncovering the new coronavirus that demonstrated a striking 72% genetic similarity to the MERS-CoV genome.
The spike protein of this newly identified virus displayed a concerning 71.74% similarity to that of MERS-CoV, raising alarm among experts. The potential for a new zoonotic virus to spill over into humans highlights the importance of ongoing surveillance and research in understanding these pathogens.
As health authorities across the globe monitor these developments, the situation underscores the need for continued vigilance and preparedness in the face of emerging infectious diseases.
