#18,999
Although the number of MERS-CoV cases reported in 2025 is a small fraction of what we were seeing a decade ago, we've seen a slow, but steady increase in numbers since the lows of 2022 (see chart above).
Meanwhile, new COVID variants continue to emerge, and over the past decade we've seen seen numerous reports of newly discovered coronaviruses circulating in the wild, many of which also appear to have zoonotic potential.
Just a few, of many, include:
Preprint: A Divergent Betacoronavirus with a Functional Furin Cleavage Site in South American Bats
J. of Infection: Novel Coronaviruses Identified in Livestock
Viruses: Novel Rodent Coronavirus-like Virus Detected Among Beef Cattle with Respiratory Disease in Mexico
Nature: Study on Sentinel Hosts for Surveillance of Future COVID-19-like Outbreaks
All of which had led to a bit of a resurgence of interest in coronaviruses in general, and MERS-CoV in particular.
Earlier this month, we looked at The Lancet: The Threat of Another Coronavirus Pandemic, while in October we reviewed Health Sci Rpts (Narrative Review): Pathogenicity and Potential Role of MERS-CoV in the Emergence of “Disease X”.Prior to COVID's arrival in late 2019, MERS-CoV was the top contender for sparking a coronavirus pandemic, sporting a high mortality rate (>30%), and spreading easily through hospitals in the Middle East (and South Korea) (see Ziad Memish: Two MERS-CoV Hospital Super Spreading Studies).
Last June we looked at an editorial in Journal of Epidemiology & Global Health on the importance of continued healthcare preparedness and surveillance (see Al-Tawfiq & Memish On Recurrent MERS-CoV Transmission in Saudi Arabia), with an emphasis on identifying asymptomatic carriers.
Three weeks ago France announced the detection of MERS-CoV in 2 travelers returning from the Middle East, reminding us that viruses have no respect for borders.
While MERS-CoV appears to be less of a threat today than it was a decade ago, it continues to evolve and adapt, making it worth keeping on our radar.
Additionally, we've seen some reluctance on the part of Middle Eastern nations to report cases, and the evidence suggests that the number of confirmed cases may substantially under represent the true incidence of human infection (something this WHO report mentions as a possibility).
A few, of many, past reports include:
Yesterday the World Health Organization published a year-end update on the global MERS-CoV situation. Due to its length, I've only posted some excerpts (highlights and emphasis mine). Follow the link to read it in its entirety.
I'll have a bit more when you return.
Middle East respiratory syndrome coronavirus - Global update
24 December 2025
Situation at a glance
Since the beginning of 2025 and as of 21 December 2025, a total of 19 cases of Middle East respiratory syndrome coronavirus (MERS- CoV), including four deaths have been reported to WHO globally. Of the 19 cases, 17 were reported by the Kingdom of Saudi Arabia (KSA), and two were reported from France.Between 4 June and 21 December 2025, the Ministry of Health (MoH) of KSA reported a total of seven cases of MERS-CoV infection, including two deaths. In addition, at the beginning of December 2025, the National IHR Focal Point (IHR NFP) for France also reported two MERS-CoV travel – associated cases; involving individuals with recent travel to countries in the Arabian Peninsula.The notification of these latest cases does not change the overall risk assessment, which remains moderate at both the global and regional levels. These cases show that the virus continues to pose a threat in countries where it is circulating in dromedary camels, with regular spillover into the human population. WHO recommends implementation of targeted infection, prevention and control (IPC) measures to prevent the spread of health care-associated infections of MERS-CoV and onward human transmission.
Description of the situation
Since the first report of MERS-CoV in the KSA and Jordan in 2012, a total 2635 laboratory-confirmed cases of MERS-CoV infection, with 964 associated deaths (Case Fatality Ratio (CFR) of 37%), have been reported to WHO from 27 countries, across all six WHO regions (Figure 1). The majority of cases (84%; n=2224), have been reported from the KSA (Figure 2). Since the beginning of 2025 and as of 21 December, a total of 19 cases have been reported to WHO. Overall, 17 cases were reported in the KSA from five regions named: Riyadh (n=10), Taif (n=3), Najran (n=2), Hail (n=1), and Hafr Al-Batin City (n=1) (Figure 3). In addition, two travel associated cases of MERS-CoV infection have been reported in France, with likely exposure occurring during recent travel in the Arabian Peninsula (Figure 3).
This disease outbreak news report focuses on the recent nine cases of MERS-CoV infection reported between 4 June - 21 December 2025: seven cases from the KSA and the two imported cases to France. The details of cases reported earlier in 2025 can be referred to in the previously published disease outbreak news on 13 March 2025 and 12 May 2025.
Between 4 June and 21 December 2025, the MoH of the KSA reported a total of seven cases of MERS CoV infection. The cases were reported from three regions: Najran (2), Riyadh (3), and Taif (2). No epidemiological links were identified between the seven cases. In addition, between 2 and 3 of December 2025, the IHR NFP for France reported two cases of MERS – CoV with recent travel to the Arabian Peninsula during the month of November.
Follow-up has been completed for all contacts and no secondary infections have been identified or reported. From September 2012, France has recorded a total of four laboratory-confirmed cases of MERS-CoV infection, including one death: two cases were reported in 2013, and the latest two cases in December 2025. All cases had been travelers exposed in the Arabian Peninsula and returning back to France.
WHO risk assessment
As of 21 December 2025, a total of 2635 laboratory-confirmed cases of MERS-CoV infection have been reported globally to WHO, with 964 associated deaths. The majority of these cases have occurred in countries on the Arabian Peninsula, including 2224 cases with 868 related deaths (CFR 39%) reported from the KSA.
A notable outbreak outside the Middle East occurred in the Republic of Korea, in May 2015, during which 186 laboratory-confirmed cases (185 in the Republic of Korea and 1 in China) and 38 deaths were reported. However, the index case in that outbreak had a history of travel to the Middle East.
Three limited healthcare-related clusters have recently been reported from the KSA, two in 2024 comprised of three and two cases each, and one in 2025 comprised of 7 cases; the previous cluster before that had been observed in May 2020, also in the KSA. Extensive contact tracing was applied in the 2025 cluster, which lead to detection of four asymptomatic and two mild cases, who fully recovered. Despite these recent clusters, zoonotic spillover remains an important mode of human infection, leading to isolated cases and limited onwards transmission between humans.
Global total cases reflect laboratory-confirmed cases reported to WHO under IHR (2005) or directly by Ministries of Health from Member States. These figures may underestimate the true number of cases if some were not reported to WHO, as they may be missed by current surveillance systems and not be tested for MERS-CoV – either due to similar clinical presentation as other circulating respiratory diseases or because infected individuals remained asymptomatic or had only mild disease. The total number of deaths includes those officially reported to WHO through follow-up with affected Member States.
The notification of these new cases does not change the overall risk assessment. WHO expects that additional cases of MERS-CoV infection will be reported from the Middle East and/or other countries where MERS CoV is circulating in dromedaries, and that cases will continue to be exported to other countries by individuals who were exposed to the virus through contact with dromedaries or their products (for example, consumption of raw camel milk, camel urine, or eating meat that has not been properly cooked), or in a healthcare setting.
Due to the similarity of symptoms with other respiratory diseases that are widely circulating, like influenza or COVID-19, detection and diagnosis of MERS cases may be delayed, especially in unaffected countries, and provide an opportunity for onward human-to-human transmission to go undetected. WHO continues to monitor the epidemiological situation and conducts risk assessments based on the latest available information.
No vaccine or specific treatment is currently available, although several MERS-CoV-specific vaccines and therapeutics are in development. Treatment remains supportive, focusing on managing symptoms based on the severity of the illness.
Although surveillance and reporting of MERS cases has always been problematic - by trivializing COVID infection and dismantling our global surveillance, testing, and reporting systems (see No News Is . . . Now Commonplace) - we've likely made it far easier for MERS-CoV cases to circulate undetected.
The obvious risk being; novel viruses that emerge at the end of a long chain of infections in a new species often become more `biologically fit' or better adapted to its host.
Recent studies suggest that the frequency, and impact, of pandemics are only expected to increase over the next few decades (see BMJ Global: Historical Trends Demonstrate a Pattern of Increasingly Frequent & Severe Zoonotic Spillover Events and PNAS Research: Intensity and Frequency of Extreme Novel Epidemics).
Which suggests this strategy grows risker with each passing day.
