The Saudi MOH website was offline for much of yesterday, so this report comes a day late.
On March 30th the MOH reported a single, critical case (63,M) from Abqiq, who reportedly had camel contact. Abqiq is a Saudi Aramco community and oil-processing facility which is located roughly 60 km southwest of Dammam.
Yesterday's report indicates at least one health care worker was exposed - and while asymptomatic - has tested positive for the virus.
While we've long known that some people can become infected with MERS and show no symptoms, it has only been in the past 18 months that the Saudis have treated these patients as `real' MERS cases (see 2015's WHO Guidance On The Management Of Asymptomatic MERS Cases).
Since then the Saudi MOH has been much better about testing asymptomatic contacts of known cases, and isolating those who test positive.Last summer we saw a large hospital outbreak (see Saudi MOH On KKUH MERS Outbreak & Increased Asymptomatic Detections) in Riyadh, which involved at least 28 cases - 21 of whom were asymptomatic. Previously the incidence of asymptomatic (or very mild) cases was estimated at about 1 in 10, so this KKUH outbreak was quite a departure from the norm.
Just last month we looked at a small outbreak that produced at least 2 asymptomatic cases (see Saudi MOH: 2nd Asymptomatic HCW In Wadi Al Dawasir Cluster).Since contact tracing and testing is easier in a hospital environment, it makes sense that most of the asymptomatic cases w know about come from hospital exposures. Unknown is how many undetected mild and/or asymptomatic cases there are in the community, and how much of a role - if any - they play in the spread of the virus.