The Middle East respiratory syndrome coronavirus (MERS-CoV) represents a new enzootic coronavirus that was initially described in 2012. The clinical scope of MERS-CoV infection in humans spans from an asymptomatic or very mild respiratory illness to severe pneumonia and multiple organ failure, with a case-fatality rate reaching 36%.
At the moment, there are no specific treatment options that were validated for MERS‐CoV infection; hence, the backbone of managing critically ill patients infected with MERS-CoV is supportive, evidence-based care. Admission to the intensive care unit is often required for close monitoring (for example, affected individuals with high oxygen requirements) or adequate organ support.
Management of Respiratory Failure and Acute Kkidney Injury
Early supportive management entails supplemental oxygen for respiratory distress and shock, as well as early mechanical ventilation for persistent hypoxemia (low levels of oxygen in the blood), or substantial respiratory distress. Patients presenting with acute respiratory distress syndrome should be given evidence-based care that involves a lung-protective ventilation strategy.
High-frequency oscillatory ventilation and high-flow oxygen should be either avoided or used with vigilance in patients with Middle East respiratory syndrome due to the lack of effectiveness in individuals with acute respiratory distress syndrome coupled with the potential to generate aerosols. Moreover, systemic corticosteroids should not be given unless required for some other indication.
Conservative fluid management is advised, especially if hypoxemia is present and there is an absence of shock. The exact timing of renal replacement therapy in patients with acute kidney injury is still controversial, and it must be noted that fluid overload at the start of such replacement has been linked to a worse outcome.
Specific Treatment Modalities
As our knowledge on interferon, ribavirin and convalescent plasma for the treatment of MERS-CoV is limited, no specific treatment can currently be officially recommended. Several clinical studies researching a combination of interferon and ribavirin showed inconsistent results.
Still, research in rhesus macaque monkeys found that there was a reduction in replication of MERS-CoV that led to better outcomes with the administration of two drugs (i.e. interferon and ribavirin) given in combination. Furthermore, in treated animals there was a significant reduction in local and systemic levels of proinflammatory markers.
Several studies from independent laboratories have promulgated the development of neutralizing monoclonal antibodies against MERS‐CoV, but we still do not have any clinical data on the topic. Drugs with potential antiviral or anti-inflammatory effects (such as anti-tumor necrosis factor agents and mycophenolic acid) may emerge as possible treatment options.
Prevention and Control
The appropriate control and prevention of MERS-CoV infection relies on the identification of the definite host, the interference in animal-to-human transmission, and the application of adequate infection control measures in healthcare settings.
Due to the known risk of transmission within hospitals and healthcare system in general, contact isolation, droplet isolation and airborne infection control precautions should be instituted – especially during aerosol-generating procedures. Until transfer, all patients should wear a face mask and they should be isolated in a closed-door room. In addition, hand hygiene should be strictly performed, and all visits should be controlled and restricted.
At the moment there is no licensed vaccine for MERS-CoV, thus its development has been the focus of many different research laboratories. Vaccination of dromedary camels is one way to reduce zoonotic transmission, although the long-term effectiveness of such a strategy remains to be seen.
In conclusion, much remains to be learned about MERS-CoV; until then, we must strive for more epidemiological research, improved surveillance, and the development of novel therapies and vaccines. In addition, the momentum of recent achievements in terms of improved apprehension of disease patterns should be continued to help the global scientific community in addressing remaining questions about this virus and the disease it causes.
- Al-Dorzi HM, Van Kerkhove MD, Peiris JSM, Arabi YA. Middle East respiratory syndrome coronavirus. In: Hui DS, Rossi GA, Johnston SL. SARS, MERS and other Viral Lung Infections: ERS Monograph 72. European Respiratory Society, 2016; pp. 21-34.
- Al-Tawfiq JA, Memish ZA. The Middle East Respiratory Syndrome Coronavirus Respiratory Infection: An Emerging Infection from the Arabian Peninsula. In: Kon K, Rai M, editors. The Microbiology of Respiratory System Infections. Academic Press, 2016; pp. 55-63.