Saudi MOH: 2 MERS Cases In Epi Week 39

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Reported MERS cases from Saudi Arabia have dropped off considerably over the summer, with just 6 cases reported in August, and - as of today's report - only 3 so far in September.   

Two of those three have come, however, in the past 72 hours.

There are questions, however, over just how sensitive the Saudi surveillance system really is, and the assumption is a good many - perhaps even most - cases go undetected.

• In November of 2013, we looked at a study published in The Lancet Infectious Diseases, that estimated for every case identified, there are likely 5 to 10 that go undetected. 
• In 2015, when Saudi Arabia had recorded fewer than 1200 MERS cases, a seroprevalence study (see Presence of Middle East respiratory syndrome coronavirus antibodies in Saudi Arabia: a nationwide, cross-sectional, serological study by Drosten & Memish et al.,) suggested nearly 45,000 might have been infected.  
• A 2016 study (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016) suggested that as much as 60% of severe Saudi MERS cases go undiagnosed. 
• Just over a year ago, in Evaluation of a Visual Triage for the Screening of MERS-CoV Patients, we looked at a study of the Saudi MERS triage system - to decide who to isolate and test as a potential  case - that found it severely lacking. 

The Saudis have scaled back the information they provide in their daily updates, but we know both cases are listed as `primary cases', are male (ages 74 & 41), and have unknown recent camel contact.

For now, these appear to be community-acquired cases, from an unknown source.

While MERS-CoV hasn't taken off the way that SARS did 16 years ago, we've seen studies (see A Pandemic Risk Assessment Of MERS-CoV In Saudi Arabia) suggesting the virus doesn't have all that far to evolve before it could pose a genuine global threat.

So we watch these daily announcements closely, looking for any signs that the pattern is changing.