Saudi Arabia Announces 4 Additional MERS-CoV Cases To End 2021

Credit CDC

#16,476

On Dec 30th, in Three Blind Spots Going Into 2022, I listed MER-CoV as one of 3 credible viral threats that are frequently under reported around the globe. 

While the COVID pandemic has no doubt hampered infectious disease reporting around the world, we've had difficulties getting good MERS-CoV data from the Middle East since the virus first emerged in 2012. 

Saudi Arabia has reported the vast majority of known cases with WHO EMRO Reporting in early November. 

At the end of October 2021, a total of 2578 laboratory-confirmed cases of Middle East respiratory syndrome (MERS), including 888 associated deaths were reported globally for a case-fatality ratio (CFR) of 34.4%. The majority of these cases were reported from Saudi Arabia, which had 2178 cases including 810 related deaths (CFR 37.2%).

Despite reporting roughly 85% of the world's cases, there are strong suspicions that the virus is chronically underreported in KSA, and likely many other Middle Eastern countries. 

• 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 2018 study, written by former Deputy Health Minister Ziad A. Memish et al. (see Evaluation of a Visual Triage for the Screening of MERS-CoV Patients), concluded that Saudi Arabia's screening process for MERS testing was `. . .  not predictive of  MERS  infection.'

• And we've seen repeated `lapses' in MERS reporting over the years - sometimes lasting months - by KSA (see Saudi MOH: 5 Months Without A MERS-COV Update) and other countries, making the relatively few cases being reported less than reassuring. 

Up until a few days ago, Saudi Arabia's MERS Surveillance website only showed 13 cases in 2021, with the last one reported in late September. This is roughly a 20-fold drop over the average number of cases reported in the 5 years before COVID (2014-2019). 

The last WHO EMRO update - released in early November - stated: No new cases of MERS were reported to WHO during the month of October 2021.  The WHO did not report any new cases in their September report, either.  

Going back to their August report, 4 cases were noted, with one going back as far as March 2021. 

During the month of August 2021, four laboratory-confirmed cases of MERS and 2 deaths were reported to WHO from Saudi Arabia. One of the deaths was of a case reported in March 2021. The four reported cases are all male, non-healthcare workers and with co-morbidities. All cases were primary cases with history of contact with dromedaries and  consumption of their raw milk in the 14 days prior to the onset of symptoms. 

Which brings us to a very recently updated list for 2021 from the Saudi MOH that adds 4 more cases (1 in October, 1 in November, and 2 in December) to their list. 

While the addition of 4 new cases is notable, so too are the facts that 2 of these cases are deceased, and 3 of the 4 appear to have had no contact with camels in the 2 weeks prior to infection, suggesting community acquired infections. 

 

While many human MERS cases have been linked to recent camel (or camel product) exposure, or had contact with a confirmed case, hundreds of others are listed as `primary' (community acquired) cases with no known risk exposure. 

The assumption is that some of these cases may be due to unidentified, mildly symptomatic (or asymptomatic) cases, who occasionally transmit the virus on to others in the community.

In 2018, the WHO listed some of the `milder' symptoms that may be associated with MERS-CoV infection, including:

Low-grade fever, cough, malaise, rhinorrhoea, sore throat without any warning signs, such as shortness of breath or difficulty in breathing, increased respiratory (i.e. sputum or haemoptysis), gastro-intestinal symptoms such as nausea, vomiting, and/or diarrhoea and without changes in mental status (i.e. confusion, lethargy).

Essentially, the same symptoms one would expect to see with mild-to-moderate COVID infection.  It is plausible that many mild MERS cases have gone undetected, due to the pandemic and other lapses in surveillance and reporting. 

Prior to the emergence of COVID-19, MERS-CoV was viewed as the coronavirus with the most pandemic potential (see 2017's Study: A Pandemic Risk Assessment Of MERS-CoV In Saudi Arabia). 

While it may not be ready for prime time, MERS-CoV continues to evolve - mostly outside of our view - making it very much worth our attention.