#MERS:Risks exposure & Risks factors in KSA

This week was posted the first case control study on MERS in KSA. Not really a surprise but new evidence on the key role of dromedary camels as the source and reservoir for MERS-CoV . Two main causes to explain the spread of MERS in KSA since 2012:

  1. Zoonosis: People indirect contact with camels are more exposed to get MERS; Camel herdsmen or slaughterhouse workers are mostly the primary cases.
  2. Nosocomial outbreak: People with underlying or pre-existing medical conditions like diabetes,cardiac or pulmonary failures,kidney disease or immuno-compromised are high risks to get MERS at the hospital whenever a lack of the infectious control protocol is occurring. Health Care Workers (HCW) are impacted but also responsible for this nosocomial outbreak.

MERS Risk Exposure and Factors_2015

 Regarding Epidemiology, this study brings up interesting data regarding the ratio primary/secondary MERS cases:

  • 6% are primary cases related to zoonosis; up to 56% died. This fatality rate is over the total MERS fatality rate around 42%.
  • 94% are secondary cases, human to human spread which occurs mostly at the hospital (Emergency room,ICU,renal dialysis) due to underlying poor medical conditions.

The flow chart above summarizes the different root causes, risk exposure and how risks factors are playing a key role in the outcome.

#MERS Coronavirus in KSA and The Conspiracy Theory

Local viewpoint:MOH has failed to control Mers.It is always alarming whenever we are facing a conspiracy theory and especially when this theory is supported by the Authorized Persons locally. Most of the time, that points out a weakness with regards the way to managing the threat of an ongoing MERS outbreak.image

Considering that things are not under and before they become out of control despite action plan (ICP) to stop a huge nosocomial infection occurring in the main national hospitals, it is easier and more convenient to elaborate a conspiracy theory. To keep in mind that 33% of Mers cases are nosocomial infection.

But such a theory does not resist to scientific peer review: MERS is existing since 2012 and coronavirus is hosted by dromedary camels since decades, starting in North then Horn of Africa before reaching Middle-East. Last year Dr Ian Mackay wrote that MERS came from camels, not terrorists

On one hand, scientists (Virologists, Epidemiologists, Veterinarians) are gathering evidence based on facts; on the other hand, there are tweets sent by honourable Faculty members denying the evidence based medecine regarding MERS-CoV.

Last, not least, The Under secretary of MOH is pleading for a “plausible” bio-weapon of MERS-Coronavirus. see ‘Plausible’ that MERS was developed as bio-weapon

Miscommunication on Mers issues and impacts?

I don’t like speculating on this matter but I would not be surprised to watch an increase of MERS cases among Hajj Pilgrims by the end of September, early October outside of KSA on their way back to home countries.

Poor risk assessment of what a bio-weapon would meet as a minimum requirement to be classified as a threat; clear demonstration of lack of knowledge about MERS which reminds me the same story heard in West Africa during the Ebola outbreak…

Imaging a bio-weapon dedicated to disable and targeting Population with chronic diseases and underlying poor medical conditions? Come on…

Towards a #MERS Vaccine? Who is the target?

Helen Branswell has recently published Camel vaccine against MERS could slow human to camel infections.

In its 10th meeting hold on september 3rd, IHR Emergency Committee of WHO addressed a couple of things related to vaccine:

WHO Statement on 10th meeting IHR/EC

  • International collaboration to develop human and animal vaccines and therapeutics should be accelerated.

Laboratories have launched their battle-field researchers in order to be the first to produce a vaccine against MERS; whatever the vaccine would be?


Since 2012, Virology and Epidemiology have brought on the table a lot of information about the virus itself, a coronavirus, same family of SARS virus.

As of today we know how MERS is operating as an infectious disease, hosted by dromadary camels mainly in Middle-East (>90% infected), starting by a zoonosis then spreading human to human through clusters in household or nosocomial infection in the hospitals.

Two kinds of infected (by Mers-Cov) population have emerged in KSA:

  • symptomatic:either elderly or People with underlying poor medical conditions or chronic diseases including but not limited to diabetes,chronic renal failure, cardio-respiratory diseases or immunosuppressed
  • asymptomatic:healthy carriers

Root causes,mitigations and prevention of MERS-CoV_2015

Identifying healthy carriers, asymptomatic ones is based on positive testing, sometimes in link with health risks exposure like camels herds owners, slaughterhouse workers, or health care workers (HCW). Even if prevalence is quite low, we have identified a life cycle for Mers infection and outbreaks (see chart).

It is not the purpose here to review the conditions for nosocomial outbreak at the hospitals; see: Follow-up of the nosocomial #MERS outbreak in Riyadh,KSA

Knowing that, how could we prevent MERS from spreading both at community hospital level and at household level? Would it be realistic to vaccine the entire KSA population or only People at high risks? Would such a vaccination program prevent actually MERS from spreading?

Or do we focus on the source of MERS Coronavirus, I mean dromadary camels and manly young calves under 5 years old? It would make more sense with a long lasting and sustainable outcome to prevent Mers coronavirus from jumping outside of animal to human; in other words to prevent a zoonosis?

The answer seems obviously understood in the question…KSA MOH is supporting and sponsoring the idea of an animal vaccine by working hard on this issue.