Although daily reporting from the Saudi MOH has faltered badly this month (see Saudi MOH Reports 2 MERS Cases), with reports issued for only 6 of the past 22 days (see list below) - last month, before reporting fell off a cliff - we saw a quadrupling of cases over what had been reported in December.
The World Health Organization's EMRO (Eastern Mediterranean Office) issues a monthly summary - usually about mid-way through the month - on the previous month's MERS activity in KSA, and the Middle East.
While these monthly reports are chock full of data, and graphs, and can help us peer into the murky MERS situation in KSA, sometimes even their numbers are difficult to reconcile.First we'll look at January's report, and then compared it to December's.
|Click to Enlarge|
- At the end of January 2018, a total of 2160 laboratory-confirmed cases of Middle East respiratory syndrome (MERS), including 773 associated deaths (case–fatality rate: 35.8%) were reported globally; the majority of these cases were reported from Saudi Arabia (1786 laboratory-confirmed cases, including 699 related deaths with a case–fatality rate of 39.1%).
- During the month of January, 25 laboratory-confirmed cases of MERS were reported in Saudi Arabia including 8 associated deaths. A nosocomial outbreak of MERS occurred in a private hospital in Hafr Albatin region, the date of onset of the first case was 23 January 2018; while on 4 February 2018, three asymptomatic healthcare workers were reported through contact tracing.
- The demographic and epidemiological characteristics of the cases reported in January 2018 do not show any significant di erence compared with cases reported during the same period from 2012 to 2017. Owing to improved infection prevention and control practices in the hospitals, the number of hospital-acquired cases of MERS has dropped significantly in 2015, 2016 and 2017 compared to previous years.
- The age group of those aged 50–59 years continues to be the group at highest risk for acquiring infection as primary cases. For secondary cases, it is the age group of 30–39 years who are mostly at risk. The number of deaths is higher in the age group of 50–59 years for primary cases and 70–79 years for secondary cases.
While the reported numbers for January are 25 new cases and 8 deaths, when you look at the ending numbers for December (see excerpt below) we find a jump of 33 cases, and 16 deaths.
At the end of December 2017, a total of 2127 laboratory-confirmed cases of Middle East respiratory syndrome coronavirus (MERS-CoV), including 757 associated deaths (case–fatality rate: 35.6%) were reported globally; the majority of these cases were reported from Saudi Arabia (1753 laboratory-confirmed cases, including 683 related deaths with a case–fatality rate of 38.9%).As to what accounts for these discrepancies?
The most likely cause is that previously unidentified cases (or deaths) may turn up after delayed or retrospective lab testing, get added to the total, yet are never detailed. We saw this happen in 2014 (see Saudi MOH: Review Finds 19 `Historical’ MERS Cases Prior to June 2014) and it likely still occurs.
Additionally - asymptomatic cases - who are tested as contacts of known cases, may not be immediately identified and may account for some back filling of data.While it would be nice to be able say with some degree of accuracy how many MERS cases have occurred in the Middle East - or around the world - the simple fact is that surveillance probably only picks up a fraction of the cases (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016).
Even with the best of outbreak surveillance and reporting, there's always a bit of `fog' to deal with.The big question, with the recent erratic reporting from the Saudi MOH, is how much visibility we're going to have going forward.