WHO MERS-CoV Update - June 19th

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The World Health Organization has published a follow-up to last week's report on the large cluster of MERS-CoV cases (50+) that have been reported in three Riyadh hospitals since the first of the month.

While it (and its accompanying spreadsheet) provide some fairly detailed information about each individual patient, we still don't know much about epidemiology of this outbreak, and what specific circumstances led to such rapid spread.

Hopefully we'll see a detailed post-mortem report published in one of the major scientific journals in the months to come. 

Middle East respiratory syndrome coronavirus (MERS-CoV) – Saudi Arabia 

Disease outbreak news
19 June 2017 

Between 11 and 15 June 2017, the national IHR Focal Point of Saudi Arabia reported 14 additional cases of Middle East Respiratory Syndrome Coronavirus (MERS-CoV) infection including one fatal case among previously reported cases.

Details of the cases

Detailed information concerning the cases reported can be found in a separate document (see link below).

• MERS-CoV cases reported between 11 and 15 June 2017.
  xlsx, 38kb

Thirteen of the 14 newly reported cases are associated with clusters 1 and 3 in the Disease Outbreak News published on 13 June 2017. Seven of the 13 newly reported cases are health care workers.

Cluster 1

This Middle East Respiratory Syndrome (MERS) cluster is currently occurring in a hospital, Riyadh city, Riyadh region. An additional nine cases have been reported in this cluster including three health care workers. In total, 32 laboratory-confirmed cases reported to WHO are associated with this cluster to date. All of the asymptomatic cases are in home isolation and all symptomatic cases are isolated on a hospital ward.

Cluster 2

No newly reported cases are associated with cluster 2 as reported in the Disease Outbreak News published on 13 June 2017.

Cluster 3

This MERS cluster is currently occurring in a third hospital in Riyadh city, Riyadh Region. In addition to the cases previously reported in the Disease Outbreak News published on 13 June 2017, the cluster involves four newly reported cases. To date, this cluster involves, including the suspected index case, eight laboratory confirmed patients all of them are health care workers, including the four newly reported cases described in the separate document (see link above).

Globally, 2029 laboratory-confirmed cases of infection with MERS-CoV including at least 704 related deaths have been reported to WHO.

Public health response

The Ministry of Health of Saudi Arabia is evaluating each case and their contacts and implementing measures to limit further human-to-human transmission and bring these outbreaks to a control. These measures include:

• Proper isolation for all confirmed cases (home isolation for asymptomatic patients, in hospital for symptomatic patients).
• Active tracing for all contacts of patients, health care workers and community contacts.
• Identification of high and low risk contacts with daily monitoring for all during incubation period of the 14 days and performing laboratory testing for high risk contacts, regardless of the development of symptoms; multiple laboratory testing is conducted during the follow-up period.
• Regular updating of the line list of cases and contacts and conducting epidemiological analysis of data to identify the source of infection, links between patients and reasons for MERS-CoV spread in the hospitals.
• Investigation of suspected cases between patients and health care workers based on case definition of MERS.
• Enforcement of strict adherence to proper environmental cleaning, disinfection and terminal cleaning and disinfection for hospital environment with special care to the departments where the outbreaks are currently occurring or have occurred.
• Enforcement of visual triage for respiratory diseases in emergency department and outpatient departments and ensure the 24/7 availability of a trained nurse for early detection of patient with respiratory symptoms, and proper documentation in triage form.
• Extensive training of all health care workers on case definition for early detection, implementation of isolation precautions, proper selection, donning and doffing of PPEs, hand hygiene and environmental cleaning and disinfection.
• Ensuring that all health care workers tested for N95 fitting (fit test).
• Ensuring availability of infection prevention supplies including hand sanitizer, PPEs, surface disinfectants, portable HEPA filters and fumigation machines.
• Enforcing the implementing of a policy of not allowing health care workers to travel without medical clearance to prevent the spread of the virus to other countries.

WHO risk assessment

MERS-CoV causes severe human infections resulting in high mortality and has demonstrated the ability to transmit between humans. So far, the observed non-sustained human-to-human transmission has occurred mainly in health care settings. Preliminary investigations of the clusters described above indicate that secondary cases are linked to two events where aerosolizing procedures were conducted in crowded medical wards under sub-optimal infection prevention and control conditions.

The notification of additional cases does not change the overall risk assessment. WHO expects that additional cases of MERS-CoV infection will be reported from the Middle East, and that cases will continue to be exported to other countries by individuals who might acquire the infection after exposure to animals or animal products (for example, following contact with dromedaries) or human source (for example, in a health care setting). WHO continues to monitor the epidemiological situation and conducts risk assessment based on the latest available information.

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