The risk assessment is reviewed on a regular basis and updated as required.
Updated: January 15, 2016
Since April 2012, cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) have been identified in the following countries in the Middle East: Jordan, Saudi Arabia (KSA), Qatar, the United Arab Emirates, Oman, Kuwait, Yemen, Lebanon and Iran. The majority of all cases reported have been from KSA.
Several other countries have also reported cases in individuals who have travelled to the Middle East: Algeria, Austria, China, Egypt, France, Germany, Greece, Hong Kong, Italy, Malaysia, the Netherlands, the Philippines, South Korea, Thailand, Turkey, Tunisia, United Kingdom and United States. There have been no cases identified in Canada.
Local transmission among close contacts who have not travelled to the Middle East have been reported in France, Italy, South Korea, Tunisia and the United Kingdom.
Since 2012, the World Health Organization (WHO) has reported over 1,600 confirmed human cases, including over 500 deaths. For the latest updates on cases and deaths please visit the Global Alert and Response website.
Epidemiologic patterns of MERS-coV reflect sporadic zoonotic infections with amplified human to human transmission in health care settings. Large outbreaks of MERS-coV have mainly resulted from nosocomial transmission in healthcare facilities due to lapses in infection prevention and control measures. Some of these large outbreaks have led to limited community transmission within households, however, sustained human to human transmission has not been observed.
Hospital associated MERS-coV outbreaks are ongoing and have occurred repeatedly in Saudi Arabia. The most recent large nosocomial outbreak occurred in Riyadh, Saudi Arabia. This outbreak began in July 2015 and was linked to one main hospital facility (King Abdul-Aziz Medical City for National Guard) with small family clusters also reported. Despite an established triage system in the hospital, a WHO mission to KSA conducted on August 23, 2015 identified overcrowded conditions in the emergency room as a key contributing factor to this outbreak.
Since early 2014 three other large outbreaks have been reported in Saudi Arabia, the UAE and Korea. The first outbreak occurred in a hospital in Jeddah, Saudi Arabia. On a mission, the WHO analyzed 128 laboratory-confirmed cases that had symptom between February 17 and April 26, 2014. An estimated 60% of all cases analyzed were reported in a hospital setting. The second hospital outbreak occurred in the UAE and resulted in a total of 28 cases in the city of Al Ain. It is unclear whether transmission occurred from the index case or from non-human sources.
The third outbreak in South Korea, which began in May 2015, is the largest nosocomial outbreak of MERS-CoV outside the Middle East. This outbreak started from a single person who travelled to four countries in the Middle East and who appears to have transmitted infection to close relatives, patients sharing the same room and health care workers providing care. These exposures happened before MERS-CoV was suspected or diagnosed. The outbreak in the Republic of Korea was declared over on December 23, 2015. Nosocomial and home-based transmission have been previously observed (e.g., in KSA, UAE, France, United Kingdom).
An increasing incidence of MERS-CoV from March-April suggests a seasonal pattern. The apparent seasonal increase in primary cases occurring for unknown reasons may be related to the weaning of young camels from their mothers in the spring of each year. In light of this and the growing evidence of a MERS-coV link between camels and humans, the WHO recommends avoiding contact with camels; not drinking raw camel milk or camel urine; and not eating meat that has not been thoroughly cooked.
The WHO provides recommendations for the general population as well as for high risk groups which include: (1) practicing general hygiene measures for those visiting places where camels are present and (2) handling with care animal products in order to avoid cross-contamination with uncooked foods. Individuals at high risk of severe disease include the following: people with diabetes, renal failure, chronic lung disease, and immunocompromised persons.
In their latest Risk assessment published on July 7, 2015 the WHO recommends enhancing prevention and control measures to prevent the spread of MERS-CoV in healthcare facilities. Additionally, WHO advises countries to be on high alert for MERS-CoV in travelers or migrant workers returning from the Middle East.
The IHR Emergency Committee concerning MERS-CoV had its 10th meeting on September 2, 2015. The consensus was that the conditions for a public health emergency of international concern (PHEIC) had not yet been met. The committee indicated that the major factors contributing to the ongoing MERS-CoV situation are insufficient awareness about the urgent dangers posed by this virus, insufficient engagement by all relevant sectors, and insufficient implementation of scalable infection control measures, especially in health care settings such as emergency departments. They noted that individual countries and the global community will remain at significant risk for further outbreaks until this is achieved. The WHO does not recommend the application of any travel or trade restrictions and considers screening at points of entry to be unnecessary at this time.
The case count of MERS-coV may not be a global reflection of the true burden of illness as surveillance systems are often unable to capture mild and asymptomatic cases. A modelling study published in November 2013 has estimated that at least 62% of symptomatic MERS-coV cases may have gone undetected note 1. Correspondingly, results from a cross-sectional serologic study published on August 2014, revealed a 5% rate of subclinical secondary MERS-coV infections following the investigation of 280 household contacts of 26 index patients note 15. There currently is insufficient epidemiological information to determine whether transmission is self-sustaining in humans and also, what role mildly symptomatic and asymptomatic cases play in disease transmission.
Research to date suggests the emergence of MERS-coV to be of bat origin before it was transmitted to camels at one point in time. Genomic sequencing and phylogenic analysis from bats in Saudi Arabia and Africa support this theory, with similarities identified between bat corona virus sequences and MERS-coV note 6- note 8. Recent studies point to the role of camels as a primary source of MERS-CoV infection in humans through direct or indirect contact with infected camels or camel-related products (e.g. raw camel milk) note 10- note 13.
The high rates of MERS-coV antibodies in the camel population and the detection of the virus in respiratory secretions, feces, and milk confirm the circulation of MERS-coV infection in dromedary camels note 9. Seroepidemiological studies have been carried out in other livestock, however, MERS-coV specific antibodies have only been identified in dromedary camels.
There is a growing body of research from the Arabian Peninsula and Africa linking MERS-coV transmission between dromedary camels and humans note 13. Genomic sequencing and epidemiologic investigations conducted in 2013, 2014, and recently in 2015 identified similarities in the genomic sequence of persons infected with MERS-coV and infected camels they had close contact with note 10- note 12. Â Additionally, other recent studies conducted demonstrate a greater risk of MERS-coV infection among individuals exposed to camels when compared to the general population note 13, note 14.
Although it is evident that MERS-coV is a zoonotic disease, the route of camel to human transmission is not fully understood. The discovery of the route of transmission between camels and humans remains critical to preventing the introduction of MERS-coV into the human population. There continues to be a need for well planned, structured investigations carried out in conjunction with exposure investigations in humans.
No vaccine or effective antiviral treatment is currently available for MERS-CoV. However, research is underway by several scientists to develop a candidate vaccine to protect humans against MERS-coV. Most recently, researchers at the National Institute of Health in collaboration with other investigators including the Public Health Agency of Canada developed an experimental synthetic DNA based vaccine that can generate protective MERS-coV antibodies in mice, marcaque monkeys, and camels. The results of the study were published on August 19, 2015 in Science translation and medicine. Inovio Pharmaceuticals and partnered company GeneOne Life Sciences will soon be leading phase 1 human trials to demonstrate the vaccines potential use. Other experimental vaccines are in development,however they require further testing before they can move to human trials.
On 4 June 2015, the WHO published guidelines for Infection prevention and control during health care for probable or confirmed cases of MERS-CoV infection.
Virus isolates have been cultured and genome sequences have been made publicly available. All five of the sequenced viruses have a high degree of genetic similarity. Preliminary analyses show that the viruses are genetically somewhat similar to bat coronaviruses, but distinct from the Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) which caused an international outbreak in 2003 in humans.
It should be noted, however, that the similarity does not necessarily imply that bats are the reservoir for the human virus or that direct exposure to bats or bat excreta were responsible for infection.
Health care professionals are encouraged to maintain vigilance for cases of MERS-CoV infection, and notify the appropriate Public Health Departments of any persons under investigation. The national case definition for MERS-CoV is to be used for the surveillance of MERS-CoV. For guidance on surveillance objectives and activities, please refer to the national surveillance guidelines for MERS-CoV.
Provinces and Territories are asked to report confirmed cases of MERS-CoV infection to the Public Health Agency of Canada using the Emerging Respiratory Pathogens and Severe Acute Respiratory Infection (SARI) Case Report Form.
Laboratory testing should be conducted in accordance with the Canadian Public Health Laboratory Network's Protocol for Microbiological Investigations of Severe Acute Respiratory Infections (SARI). Follow infection prevention and control guidelines when collecting respiratory specimens. Be aware of approaches in your jurisdiction.
Laboratory confirmation is obtained by detection of the virus using (a) MERS-CoV specific nucleic acid amplification test (NAAT) with up to two separate targets and/or sequencing; or (b) virus isolation in tissue culture note a; or (c) serology on serum tested in a WHO collaborating center with established testing methods. Initial screening tests specific for MERS-CoV can be performed in select laboratories (i.e. primarily provincial public health laboratories); however, such cases are considered probable pending NML confirmation. Â Laboratories with specimens that screened positive for MERS CoV should forward these to their local public health laboratory (PHL) that can facilitate confirmatory testing at the NML.
For more detailed information, refer to the National Surveillance Guidelines for Human Infection with Middle East Respiratory Syndrome Coronavirus (MERS-CoV).
The WHO published interim recommendations for laboratory testing for MERS-CoV. (September 2014).
A travel health notice is posted on the Agency's website. It does not recommend any restrictions on travel but encourages travelers to take routine precautions.
Health care facilities are reminded of the importance of systematic implementation of infection prevention and control (IPC) measures. Health care facilities that provide care for patients suspected or confirmed with MERS-CoV infection should take appropriate measures to decrease the risk of transmission of the virus to other patients, health care workers and visitors. Recommendations for infection prevention and control measures for patients presenting with suspected or confirmed infection or co-infection with MERS-CoV in acute care settings is posted on the Agency's website. This guidance will be updated as new information becomes available.
MERS-CoV is classified as a Risk Group 3 human pathogen given that this virus can cause serious illness in humans, while the public health risk is low since the risk of spread of the virus in the community appears to be low. Containment Level 3 is required for all proliferative work (in vitroor in vivo), and non-proliferative diagnostic activities can be conducted at Containment Level 2 with the use of additional operational practices as outlined in Biosafety Advisory: Middle East Respiratory Syndrome Coronavirus (MERS-CoV).