Disease Outbreak News Middle East respiratory syndrome coronavirus – Kingdom of Saudi Arabia

On 5 September 2024, the Ministry of Health (MoH) of the Kingdom of Saudi Arabia (KSA) notified the World Health Organization (WHO) of one case of Middle East respiratory syndrome coronavirus (MERS-CoV).

The case, a man aged between 50-55 years residing in the Eastern Region of KSA, developed a fever, cough, shortness of breath, and palpitations on 28 August 2024. He was admitted as a cardiac case to a local hospital on 31 August and transferred to a medical complex on 1 September. From there he was discharged at his request the same day, against medical advice.

A nasopharyngeal swab taken on 1 September and tested at the National Public Health Laboratory as part of severe acute respiratory illness (SARI) sentinel surveillance, returned a positive result for MERS-CoV on 4 September through Real-Time Polymerase Chain Reaction (RT-PCR).

After the patient was discharged from the hospital and prior to receiving the laboratory results confirming MERS-CoV, he traveled to Pakistan on 2 September.

The patient is a non-healthcare worker with several co-morbidities. Following field investigation, there was no evidence of interaction with camels. In KSA, follow-up has been completed for one household member, 23 healthcare professionals, and two patients who had contact with the case, with no secondary cases reported. Among close contacts listed in KSA, one travelled from Saudi Arabia to South Asia on 4 September. Flight details and personal information were retrieved to initiate contact tracing and follow-up, and no secondary cases have been identified in connection with this high-risk contact.

Following the notification on 5 September 2024 from the International Health Regulations (IHR) National Focal Point (NFP) of KSA to the Pakistan IHR NFP regarding the patient’s travel and positive MERS-CoV results, the patient was located in Pakistan, and the health authorities proceeded to transfer the patient to a public hospital for strict isolation and management of existing comorbidities.

A total of 41 nasopharyngeal samples, including repeat samples of the case and close contacts were collected and tested at the Pakistan National Institute for Health/National Reference Laboratory. The patient tested positive, albeit with a low viral load, while all contacts tested negative. Close contacts, including family members and healthcare workers were closely monitored for 14 days, and no secondary cases have been identified.

The patient was discharged on 13 September after receiving a negative test result for MERS-CoV, along with instructions to continue oral medication and to return for a follow-up appointment in five days. This follow-up was successfully completed on 19 September, confirming the patient’s full recovery.

Since the beginning of the year, a total of five cases including four deaths have been reported from KSA, and this is the first case reported since the last Disease Outbreak News was published on 8 May 2024.

Middle East respiratory syndrome (MERS) is a viral respiratory infection caused by MERS-CoV. The mortality rate among MERS patients is approximately 36%. However, this figure may be inflated due to the potential underreporting of mild cases that are not detected by current surveillance systems, and the case fatality ratio (CFR) is calculated based only on laboratory-confirmed cases.

Humans acquire MERS-CoV through either direct or indirect interaction with dromedary camels, which serve as the virus’s natural host and zoonotic reservoir. MERS-CoV has demonstrated the ability to transmit between humans. To date, instances of non-sustained human-to-human transmission have been observed primarily among close contacts and within healthcare environments. Outside of health care settings there has been limited human-to-human transmission to date.

MERS disease can manifest in a spectrum ranging from asymptomatic cases to mild respiratory symptoms, and in more severe instances, it can lead to acute respiratory distress and mortality.

Common symptoms associated with MERS include fever, cough, and difficulty breathing. Pneumonia is a common finding, but not always present. Additionally, gastrointestinal symptoms such as diarrhea have been documented. In severe cases, the illness may result in respiratory failure, necessitating mechanical ventilation and support in an intensive care unit. The virus tends to induce more severe outcomes in older adults, persons with weakened immune systems, and those with underlying health conditions such as renal disease, cancer, chronic lung disease, and diabetes.

The number of MERS-CoV cases reported to WHO substantially declined during the COVID-19 emergency. Initially, this decline was likely attributable to the prioritization of epidemiological surveillance efforts for COVID-19. The overlapping clinical presentations of both diseases may have led to a decrease in the testing and detection of MERS-CoV cases. Since 2022, the Ministry of Health of KSA has been working to improve testing capacities for better detection of MERS-CoV by including MERS-CoV into sentinel surveillance testing algorithms, following negative test results for influenza, Respiratory Syncytial Virus (RSV), and SARS-CoV-2 (responsible for COVID-19). Furthermore, the public health measures implemented to curb the transmission of SARS-CoV-2—such as mask-wearing, hand hygiene, physical distancing, improved indoor ventilation, respiratory etiquette, stay-at-home orders, and reduced mobility—are also likely to have diminished the chances of human-to-human transmission of MERS-CoV. Potential cross-protection conferred from infection with or vaccination against SARS-CoV-2 and any reduction in MERS-CoV infection or disease severity and vice versa has been hypothesized but requires further investigation.

At present, there is no vaccine or targeted treatment available; although several MERS-CoV-specific vaccines and therapeutics are in development. Treatment is supportive and tailored to the clinical status and symptoms of the patient.

The Ministry of Health of KSA and Pakistan implemented active contact tracing with daily monitoring throughout the 14-day incubation period and laboratory testing for high-risk contacts. Triage for respiratory diseases has been implemented in the hospitals to enable early detection of patients with respiratory symptoms.

In addition, comprehensive refresher training on case definition has commenced in Pakistan for all health and care workers to ensure early detection of cases. Concurrently, training sessions focused on the application of infection prevention and control (IPC) standards, as well as transmission-based precautions pertaining to MERS-CoV, are currently in progress, while ensuring the availability of IPC supplies such as hand sanitizers and personal protective equipment (PPE). Additionally, health awareness sessions have been arranged for all family members of the affected individuals.

WHO is launching updated MERS-CoV Unity Study protocols to support Member States in MERS-CoV studies and investigations.

Since the first report of MERS-CoV in the Kingdom of Saudi Arabia (KSA) in 2012 until now, human infections have been reported in 27 countries, spanning all six WHO regions. The majority of MERS-CoV cases (2205; 84%), have been reported in KSA, including this newly reported case.

The notification of this case does not change the overall risk assessment. The new case reported is believed to have acquired MERS-CoV infection locally within KSA. However, the potential for international transmission is increased due to the fact that the individual visited Pakistan, while a high-risk contact traveled to South Asia within the 14-day follow-up period. Both individuals had arranged their travels prior to the occurrence of the event and before the test results of the case were obtained and disseminated.

WHO expects 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. In addition, 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 raw camel milk), or in a health-care setting. Human-to-human transmission of MERS-CoV may occur if there are delays in identifying the infection, particularly in countries that are not well-acquainted with the disease, as well as slow triage of suspected cases and delays in the implementation of standard infection prevention and control measures.

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

Based on the current situation and available information, WHO re-emphasizes the importance of strong surveillance by all Member States for acute respiratory infections, including MERS-CoV, into the testing algorithm were warranted and to carefully review any unusual patterns.

Human-to-human transmission of MERS-CoV in health-care settings has been associated with delays in recognizing signs and symptoms of MERS-CoV infection, delayed isolation of suspected cases and delays in implementing Infection prevention and control (IPC)measures. IPC measures are critical to prevent the possible spread of MERS-CoV between people in health-care facilities. Health and care workers should apply standard precautions consistently with all patients at every interaction in health-care settings. Droplet precautions should be added to the standard precautions when providing care to patients with symptoms of acute respiratory infection; contact precautions and eye protection should be added when caring for probable or confirmed cases of MERS-CoV infection; airborne precautions should be applied when performing aerosol-generating procedures or in settings where aerosol- generating procedures are conducted. Early identification, case management and isolation of cases, quarantine of contacts, together with appropriate infection prevention and control measures in health-care settings (including preventing overcrowding), and public health awareness can prevent human-to-human transmission of MERS-CoV.

MERS-CoV appears to cause more severe disease in people with underlying health conditions such as diabetes, renal failure, chronic lung disease, and immunocompromised persons. Therefore, people with these underlying medical conditions should avoid close contact with animals, particularly dromedaries, when visiting farms, markets, or barn areas where the virus may be circulating. General hygiene measures should be followed, such as regular hand washing with soap and water or hand hygiene with alcohol-based hand rub, before and after touching animals. Contact with sick animals should be avoided.

Food hygiene practices should be observed. People should avoid drinking raw camel milk or camel urine or eating meat that has not been properly cooked.

WHO does not advise special screening at points of entry regarding this event, nor does it currently recommend the application of any travel or trade restrictions.