Tuesday, May 17, 2022

WHO Update: MERS-CoV In Oman


Saudi Arabia - which has reported roughly 90% of the MERS-CoV cases in the Middle East since it emerged in 2012 - has been conspicuously silent on any new infections since last December (see WHO Update: Middle East Respiratory Syndrome Coronavirus (MERS-CoV) – Saudi Arabia). 

But today we have the 2nd MERS update from a neighboring country in a week (see Qatar report); this time from Oman.

As we've discussed previously, detecting MERS-CoV cases can be challenging, even when countries are actively looking for cases. A task has which has admittedly become even more difficult due to the COVID pandemic. 

EID Journal: Sensitivity and Specificity Of MERS-CoV Antibody Testing

AJIC: Intermittent Positive Testing For MERS-CoV

JIDC: Atypical Presentation Of MERS-CoV In A Lebanese Patient

But the reality is that some countries have been hesitant - or slow - to investigate and/or report cases, and it is assumed that the roughly 2,600 known cases over the last decade represent a significant under-count (see EID Journal: Estimation of Severe MERS Cases in the Middle East, 2012–2016).

We have the latest WHO update below, after which I'll return with a brief postscript. 

Middle East respiratory syndrome coronavirus - Oman
17 May 2022

Situation at glance

On 28 April 2022, WHO was notified of a case of Middle East Respiratory Syndrome Coronavirus (MERS-CoV), in a 34-year-old male, from Al Dhahira Governorate in Oman. The case had a history of direct contact with animals including dromedaries, sheep and goats at his family farm in Oman. The condition of the case remains critically unstable. As of 28 April, a total of six close community and 27 health care workers had been listed as contacts and were followed for 14 days from the date of last exposure with the case. No secondary cases have been reported to date.

Description of the case

On 28 April 2022, the National IHR Focal point of Oman notified WHO of one case of MERS-CoV from Al Dhahira Governorate in Oman.

The case, a 34-year-old male, non-health care worker who is a resident of Al Dhahira Governorate, developed symptoms including shortness of breath, high-grade fever, and dry cough on 18 April which lasted for six days. On 24 April, he was taken to the emergency department of a hospital. Upon examination and assessment, he was found to be in severe respiratory distress, febrile, and hypotensive and diagnosed with clinical pneumonia with fluid collection in the lungs and was admitted to the isolation ward. The condition of the patient deteriorated, and he was immediately transferred to a negative pressure isolation room, in the medical ward on the same day. On 25 April, his condition worsened, and he was then transferred to an isolation room in the Intensive Care Unit (ICU) and placed on mechanical ventilation. Respiratory samples were tested for several viral pathogens, including severe acute respiratory syndrome coronavirus (SARS-CoV) and Mycobacterium tuberculosis. A sepsis workup including blood and urine tests was performed and tested positive for MERS-CoV by reverse transcription polymerase chain reaction (RT-PCR) on 27 April.

As of 8 May, the condition of the patient remains critically unstable and he continues to be mechanically ventilated in an isolation room in the ICU. The patient has no known co-morbidities. There was no history of contact with similar cases, no history of travel nor previous hospitalization. However, the patient has a history of direct contact with animals including dromedaries, sheep and goats at his family farm in Oman.

Epidemiology of the disease

Middle East respiratory syndrome (MERS) is a viral respiratory infection that is caused by a coronavirus called Middle East Respiratory Syndrome Coronavirus (MERS-CoV). Infection with MERS-CoV can cause severe disease resulting in high mortality. Approximately 35% of patients with MERS have died, but this may be an overestimate of the true mortality rate, as mild cases of MERS-CoV may be missed by existing surveillance systems and until more is known about the disease, the case fatality rates are counted only amongst the laboratory-confirmed cases.

Humans are infected with MERS-CoV from direct or indirect contact with dromedary camels who are the natural host and zoonotic source of the MERS-CoV infection. MERS-CoV has demonstrated the ability to transmit between humans. So far, the observed non-sustained human-to-human transmission has occurred among close contacts and in health care settings. Outside of the healthcare setting there has been limited human-to-human transmission.

MERS-CoV infections range from showing no symptoms (asymptomatic) or mild respiratory symptoms to severe acute respiratory disease and death. A typical presentation of MERS-CoV disease is fever, cough and shortness of breath. Pneumonia is a common finding, but not always present. Gastrointestinal symptoms, including diarrhoea, have also been reported. Severe illness can cause respiratory failure that requires mechanical ventilation and support in an intensive care unit. The virus appears to cause more severe disease in older people, persons with weakened immune systems and those with chronic diseases such as renal disease, cancer, chronic lung disease, and diabetes.

No vaccine or specific treatment is currently available, although several MERS-CoV specific vaccines and treatments are in development. Treatment is supportive and based on the patient’s clinical condition.

Public health response
  • As of 28 April, a total of six close community and 27 health care workers were listed as contacts and followed up for 14 days from the last date of exposure to the MERS-CoV patient. All high-risk contacts, such as healthcare workers, were monitored for symptoms and screened for MERS CoV by RT-PCR as per the Ministry of Health Infection Prevention and Control guideline for MERS-COV exposures and cases. No secondary cases have been reported to date from Oman.
  • Infection, prevention and control (IPC)measures were implemented in the hospital where the patient was admitted.
  • Healthcare workers were educated on MERS and a refresher training course on IPC measures was provided.
  • Family members identified as close contacts of the case were educated on personal and respiratory hygiene to prevent further transmission
  • The Ministry of Agriculture has investigated the farms of the patient’s family and close relatives; samples from the dromedaries have been collected for testing. As of 8 May 2022, results remain pending.
WHO risk assessment

Cases of MERS-CoV infection are rare in Oman. Since June 2013, a total of 25 MERS-CoV cases, including the current case, and seven deaths, have been reported to WHO from Oman.

As of 15 May 2022, the total number of laboratory-confirmed MERS-CoV infection cases reported globally to WHO is 2591 including 894 associated deaths. The majority of the reported cases have occurred in countries in the Arabian Peninsula. Outside of this region, there has been one large outbreak in the Republic of Korea, in May 2015, during which 186 laboratory-confirmed cases (185 in Republic of Korea and 1 in China) and 38 deaths were reported. The global number reflects the total number of laboratory-confirmed cases and deaths reported to WHO under International Health Regulations (2005) to date.

The notification of this case does not change the overall risk assessment for MERS. It is expected that additional cases of MERS-CoV infection will be reported from the Middle East and/or other countries where MERS-CoV is circulating in dromedaries, and that cases will continue to be exported to other countries by individuals who were exposed to the virus through contact with dromedaries or their products (for example, consumption of camel’s raw milk), or in a healthcare setting.

WHO continues to monitor the epidemiological situation and conducts a risk assessment based on the latest available information.

          (Continue . . . )

Prior to the emergence of COVID in late 2019, MERS-CoV was at the very top of our coronavirus worry list. While not nearly as transmissible as SARS-CoV-2, MERS-CoV does appear to have a much higher case fatality rate.  

Past studies (see A Pandemic Risk Assessment Of MERS-CoV In Saudi Arabia) have suggested the virus doesn't have all that far to evolve before it could pose a genuine global threat.

And while it remains mostly a theoretical concern, several studies have suggested that there it at least some potential for seeing a MERS-CoV/SARS-CoV-2 recombinant emerge someday. 

The Recombination Potential between SARS-CoV-2 and MERS-CoV from Cross-Species Spill-over Infections

All reasons why we need to be doing a much better job looking for cases, and reporting them promptly.  Otherwise, we risk being blindsided by the next global health threat.