Middle East respiratory syndrome coronavirus (MERS-CoV) was
first identified in 2012 and since then, sporadic but continued outbreaks have
been occurring within the Arabian Peninsula. There have been 2,428 cases of the
coronavirus since 2012, and 838 associated deaths. Reported across 27
countries, this has been a disease that seems to have found a stronghold and
established itself as endemic.
MERS-CoV challenges response in that while we have diagnostic testing now, there truly is not treatment outside of supportive measures. Spread through the respiratory secretions of infected individuals, there has also been transmission via close contact (i.e. caring or living with an infected person), and ongoing investigation into the role of camels in zoonotic transmission. The disease does circulate in dromedary camels in Africa, the Middle East, and southern Asia, but cases have tended to be related to healthcare exposures and household contacts, with some camel-to-human transmission occurring. Hospitals are encouraged to ensure adherence to Standard, Contact, and Airborne isolation precautions, meaning that the patient should be placed in a negative pressure isolation room and healthcare workers should wear a gown, gloves, eye protection, and N95 respirator. Given the need for these isolation precautions, it’s not surprising that exposures often come from delays in isolation and crowded emergency rooms.
MERS-CoV has taught us a lot about outbreak response to a novel, airborne-transmitted organisms and frankly, it’s been a hard lesson for healthcare. The 2015 outbreak in South Korea was a particularly harsh moment for healthcare facilities, as 186 cases occurred and 83% were related to five superspreaders. Estimates of where exposure occur have placed healthcare-associated transmission responsible for 92-98% of the cases. From a healthcare culture that encourages “doctor shopping”, to the practice of having family/visitors participating in patient care, and roughly four patient beds per hospital room, this was a ripe environment for transmission of airborne organisms.
A recent report from the CDC in their Morbidity and Mortality Weekly (MMWR) offers an optimistic view though of the progress being made. The report finds that from 2012 through May 31, 2019, there has been a decline in cases of MERS-CoV worldwide. “Although 739 cases were reported in 2014 and 768 cases in 2015, only 244 cases were reported in 2016, another 244 in 2017, and 113 through September 2018.” Moreover, the incidence of community-acquired cases have dropped over the years, which helped divert secondary cases related to community transmission. Researchers estimated that 154 secondary cases were averted from the 177 community-acquired cases in 2016 and the total number of cases averted in 2016 (camel-to-human transmission and human-to-human transmission) was 507. This progress has been lauded as a result of enhanced surveillance and knowledge regarding control measures, as well as faster diagnostic capability.
Ultimately, MERS-CoV might be slowing down in the rate of transmission, but its lingering presence should be a testament to the serious threat of zoonotic diseases and the role of hospitals in transmission. The small blips of cases that occur and quickly burn out, much like Ebola, are often quickly stifled by public health response, however the disease has shown that it can rapidly be transmitted through healthcare facilities despite evidence-based measures for control and prevention. The complex dynamics of camel-to-human transmission are also worrisome in that we are just starting to understand the small interactions that lead to spillover. MERS-CoV may get the attention or worry that Ebola does, but we should see it as a canary in the coal mine for the resilience for zoonotic diseases and the vulnerabilities that exist in critical infrastructure.
Saskia Popescu, PhD, MPH, MA, CIC, is an infection prevention epidemiologist and biodefense researcher whose work primarily focuses on the role of infection prevention in global health security and biodefense efforts. She holds a PhD in Biodefense from George Mason University, a Master’s in Public Health in Epidemiology, a Masters of Arts in International Security Studies, and a Bachelor’s Degree in Classical History, with a specialization on disease in ancient Rome, from the University of Arizona. She is a certified infection preventionist and fellow of the Johns Hopkins Center for Health Security Emerging Leaders in Biosecurity Initiative. She can be reached at firstname.lastname@example.org