WHO: MERS-CoV Summary & Literature Update – March 27th

Figure 1. Laboratory confirmed cases of MERS‐CoV infection by approximate time of onset, March 2012 through March 2014.

 

 

# 8409

The World Health Organization released a 5-page PDF summary and literature update on the MERS coronavirus today, which seeks to characterize the first 206 reported human cases originating on the Arabian Peninsula.

 

I’ve only excerpted a small portion, follow the link to read it in its entirety.

 

 

Middle East Respiratory Syndrome Coronavirus (MERS‐CoV)      

Summary and literature update  – as of 27 March  2014   

Since April 2012, 206 laboratory confirmed cases of human infection with Middle East respiratory syndrome coronavirus (MERS‐CoV) have been reported to WHO, including 86 deaths (Figure 1). 

The age and gender distribution of cases vary depending on the presumed type of exposure that led to infection. Primary cases, those who have no history of prior exposure to other human cases, are on average older and a larger percentage of them are men than secondary cases (Table 1). Secondary cases are those who appear likely to have been infected by other humans.

Thus far, the affected countries in the Middle East include Jordan, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates (UAE), all of which appear to have had primary transmission events from non‐human sources. Other affected countries include France, Germany, Italy and the United Kingdom (UK), in Europe and Tunisia, in North Africa. In these countries, cases have been imported from the Middle East with some secondary transmission (Figure 2). All primary cases have had their exposure to MERS‐CoV in the Middle East.

Since the last update of 20 January 2014, 28 laboratory‐confirmed cases, including 10 deaths, have been reported to WHO.  Countries in which the presumed exposure of these cases occurred are shown in Table 2 below.

It is notable that the cases from Jordan, Kuwait, and one of the cases from UAE appear to have acquired infection in a healthcare setting. Among the 22 cases reported from Saudi Arabia, 19 were in Riyadh, and one appears to have acquired his infection in a health care setting.  Among the four cases that acquired infection in a health care setting, three appear to have had exposure to an unidentified primary case.

Additionally, four of the cases from Riyadh were members of the same household: the index case, a 19‐year‐old male, died as a result of infection with MERS‐CoV, and three presumed secondary cases — a 53‐year‐old male, an 18‐year‐old female and a 22‐year‐old  female—exhibited mild or no symptoms. 

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WHO MERS-CoV Summary Update #13 – January 20th

Credit WHO Summary Update #13

 

# 8194

 

 

The World Health Organization has today published a 5-page (PDF file) summary update on the MERS coronavirus, along with selected MERS-CoV Literature, and upcoming MERS-CoV Activities and guidance.

 

Included are new details on the two `probable’ MERS cases detected in Spain last November (see Spain Reports First MERS-CoV Case & Spain: MOH Statement On MERS-CoV Case).

Due to its length I’ve only included some excerpts.  Follow the link for the entire document, and links to guidance, recent additions to the literature, and WHO MERS related activities.

 

Middle East respiratory syndrome coronavirus (MERS-CoV) summary and literature update–as of 20 January 2014

Since April 2012, 178 laboratory-confirmed of human infection with Middle East respiratory syndrome coronavirus (MERS-CoV) have been reported to WHO, including 76 deaths (Figure 1).  The median age of all lab-confirmed cases (n=178) is 52 years; this varies by the presumed type of exposure. For primary cases, those who have no history of exposure to other human cases, median age is 58 years; for secondary cases, those who appear to have been infected by other humans, median age is 44 years.   Overall, 62% are male; distribution by sex also varies by presumed exposure 76% male among primary cases; 53% among secondary cases).  To date, affected countries in the Middle East include Jordan, Kuwait, Oman, Qatar, Saudi Arabia and the United Arab Emirates UAE)and; in Europe countries affected include: France, Germany, Italy and the United Kingdom (UK) and; and in North Africa: Tunisia.  All cases have a link to the Middle East. For those cases reported outside the Middle East, the link is either through recent travel to the region or exposure to a patient who acquired infection in the region. Since the last update of 22 November 2013, 21 laboratory-confirmed cases, including seven deaths, were reported to WHO. The geographic distribution of these 21 cases is 14 cases, including four deaths, from Saudi Arabia; six cases, ncluding two deaths,  from UAE; and one fatal case from Oman (Figure 2).  

Among the six new cases reported from UAE, three were from one family  in Abu Dhabi,  including a 32-year-old pregnant woman who died on 2 December 2013. Before her death, the woman gave birth to a healthy baby, who had no evidence of MERS-CoV infection. One of the recent cases from UAE was a 33-year-old health care worker who provided direct care for a 68-year-old patient with laboratory-confirmed MERS-CoV infection. The health care worker subsequently developed severe disease requiring mechanical ventilation and haemodialysis, and died.

 

Among the new cases reported from Saudi Arabia, seven are classified as sporadic (no contact with a probable or confirmed MERS-CoV patient) and seven as secondary cases (infection presumed to be acquired by transmission from another human case). Of the seven secondary cases, six are health care workers who were reported to be asymptomatic.  

<SNIP>

 

Summary assessment

Infections acquired in health care facilities currently account for more than half of secondary cases. Health care workers and other patients in contact with cases both appear to be at risk. Thus far, transmission in health care facilities does not appear to persist over long periods of time or extend into the community. Most secondary cases who acquired infection  in this setting have been mild or asymptomatic; however, several have had severe disease and have died, including workers who provided care for infected patients.   Health care providers should be reminded of the need for universal precautions and for infection control measures to be implemented even before the cause of a patient’s illness has been determined. Patients for whom clinical suspicion of MERS-CoV is high should be managed as potentially infected, even if an initial test on a nasopharyngeal swab is negative. Repeat testing should be done when the clinical and epidemiological picture suggests MERS-CoV when initial testing is negative, preferably on specimens from the lower respiratory tract. Infection control guidelines for both home care settings and health care facilities can be found on the WHO MERS-CoV website.

Despite the  initial report of probable MERS-CoV cases in Spain, follow-up laboratory testing was unable to confirm MERS-CoV infection in these two patients using specific RT-PCR assays.  The women, who had been on an extended visit to Saudi Arabia, raised initial concerns about possible infection related to the pilgrimage of Hajj, which occurred 13 to 18 October 2013. However, other than these two unconfirmed cases, there were no other reports of Hajj-related MERS-CoV patients, despite extensive testing in nearly every country  from which Hajj pilgrims originated. At this point, it is clear that neither significant transmission nor exportation of MERS-CoV occurred in association with the Hajj.

The confirmation of MERS-CoV virus in camels in Qatar supports  an earlier report of MERS-CoV in a camel in Saudi Arabia and serologic evidence of MERS-CoV in camels from Canary Islands, Egypt, Jordan, Oman and UAE.  The earliest findings of antibodies in camels from 2003 in UAE suggest that a similar virus has been circulating in animals for at least a decade. However, most primary human cases do not have a history of direct exposure to animals. More work is needed to determine the route of transmission to humans and the types of exposures that result in infection. 

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WHO MERS-CoV Summary & Update – Sept 20th

Photo Credit WHO

 

# 7797

 

 

The World Health Organization has released a second MERS update today, this time a detailed summary and literature update on what we know about the MERS coronavirus.  Due to its length, I’ve only excerpted portions.  Follow the link to read it in its entirety.

 

A few selected excerpts (bolding mine):

• Since the last update, 37 new laboratory-confirmed cases of MERS-CoV have been reported; these include 34 cases from KSA and three cases from Qatar
• Two cases previously counted as confirmed have been reclassified as probable on the basis of further clarifications of the case definition (see MERS-CoV: WHO Update Sept 20th)
• Nine new cases were reported to be sporadic, i.e. cases that were reported to have no prior contact with another known case and including cases that were the first case within a cluster. Of these, 56% were female; the median age was 53 years; and 89% had at least one underlying condition reported.
• Eighty-nine percent were severely ill or died. Eight of these cases were probably exposed to the virus in KSA (six in Riyadh, one in Medina, one in Hafr Al Batin) and one in Qatar. The median age and gender balance of these nine new cases represents a shift compared with earlier cases. Up until mid-July 2013, the median age of sporadic cases was 59.5 years and 83% were male.
• Patients with positive serological tests in the absence of PCR or sequencing data continue to be classified as probable cases, pending more work on the validation of serological tests.
• The recent upsurge in case reporting is of concern and represents both an increase in sporadic cases and several coincident clusters of infection in contacts. These clusters are under close observation by health authorities to detect signs of further onward transmission. The reason for the increase in sporadic cases is unknown but could be the result of increased surveillance, an expansion of the virus in the unknown reservoir, seasonal variation, or a change in exposure patterns
• The discovery of antibodies reactive with MERS-CoV in Egyptian camels imported from Sudan and other East African countries is consistent with the previous report by a lab in the Netherlands (see last update).  . . . . It is also unclear whether camels, even if they are infected with the virus, play a role in transmission to humans
• Countries outside of the affected region should maintain a high level of vigilance, especially those with large numbers of travellers or guest workers returning from the Middle East. Surveillance should be enhanced in these countries according to WHO guidelines along with infection control procedures in health care facilities.

There is a lot more in this update, including summaries of recent research papers, so follow the link to read:

 

Middle East respiratory syndrome coronavirus (MERS-CoV) summary and literature update – as of 20 September 2013

Since April 2012, 130 laboratory-confirmed and 17 probable cases of human infection with Middle East respiratory syndrome coronavirus (MERS-CoV) have been reported to WHO. Affected countries in the Middle East include Jordan, Kingdom of Saudi Arabia (KSA), the United Arab Emirates (UAE), and Qatar; in Europe countries affected include: France, Germany, the United Kingdom (UK) and Italy; and in North Africa: Tunisia. Infections presumably acquired through exposure to non-human sources have all occurred in the Middle East; limited transmission in the countries of Europe and North Africa has occurred in close contacts of recent travellers from the Middle East. No new countries have reported MERS-CoV cases since the last update; the last exported case to a country outside the Middle East was in June 2013.

 

Since the last update, 37 new laboratory-confirmed cases of MERS-CoV have been reported; these include 34 cases from KSA and three cases from Qatar. In addition, one previously reported probable case in Tunisia has now been confirmed as a result of additional laboratory testing. Two cases previously counted as confirmed have been reclassified as probable on the basis of further clarifications of the case definition. Of the 130 confirmed cases, 58 (45%) have died. Seventy-seven of 124 confirmed cases (63%) for which sex is known were male and the median age of the 125 confirmed cases with known age is 50 years (range, 14 months to 94 years).

 

Nine new cases were reported to be sporadic, i.e. cases that were reported to have no prior contact with another known case and including cases that were the first case within a cluster. Of these, 56% were female; the median age was 53 years; and 89% had at least one underlying condition reported. Eighty-nine percent were severely ill or died. Eight of these cases were probably exposed to the virus in KSA (six in Riyadh, one in Medina, one in Hafr Al Batin) and one in Qatar. The median age and gender balance of these nine new cases represents a shift compared with earlier cases. Up until mid-July 2013, the median age of sporadic cases was 59.5 years and 83% were male.

Three recent outbreaks are described below:

• Five cases were reported in Medina. The first Saudi case reported was a 55-year-old male who had probable contact with a 59-year-old Qatari male, who was in Medina at the time of onset of illness. The remaining cases were contacts of confirmed cases and included two asymptomatic health care workers identified through contact tracing. One additional health care worker, who died in the course of his illness, was reported without information about contact with other confirmed cases. None of the cases was reported to have performed pilgrimage while in Medina.
• Two clusters were reported in Riyadh. In a cluster of six cases, one male index case aged 53 years is thought to have infected five other cases, including two health care workers. Both health care workers experienced mild illness. In the second cluster, all three cases were health care workers. A 41 year old Filipino healthcare worker who did not have any contact to confirmed cases of MERS-CoV infections acquired the disease from an unknown source and is thought to have transmitted it to two more healthcare workers. During this same period of time, an additional four sporadic cases were reported (mentioned above) with no contact with known cases, and five with no information on exposure.
• The first case of the cluster in Hafr Al Batin was a 38-year-old male with onset of illness in early August. Five family members ranging in age from 7 to 79 years subsequently became infected. Two children aged 3 and 18 years and one 74 year-old female were also reported as contacts of a known case but their connection with this family was not reported.

For further details regarding the cases please refer to:

• Disease Outbreak News

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WHO: MERS-CoV Summary – August 13th

Photo Credit WHO

 

# 7570

 

 

The World Health Organization published their 10th summary & literature update on the MERS Coronavirus today.  Follow the link to read the entire update, including the list of recently published WHO Guidance, and recent peer-reviewed literature. 

 

I’ve excerpted portions from the Summary Assessment below:

 

 

Middle East respiratory syndrome coronavirus (MERS-CoV) summary and literature update – as of 13 August 2013

(EXCERPT)

SUMMARY ASSESSMENT

Although new cases continue to occur in the Arabian Peninsula, no new exported cases have been reported since June despite a surge in pilgrims to Saudi Arabia to perform Umra during Ramadan. The KSA Ministry of Health also reports finding no MERS-CoV infections among pilgrims during their enhanced surveillance activities. However, as Ramadan ended on 8 August and the incubation period for MERS-CoV can be as long as 10 days or more, continued vigilance is suggested. It is notable that only one previously reported case became ill after a pilgrimage.

 

As case finding and contact tracing around cases increases, increasing numbers of secondary cases with mild disease have been reported, indicating a broader spectrum of disease than previously recognized. However, transmission continues to be limited in clusters and does not appear to be extending into the wider community. Although the pattern may be changing slightly, index and sporadic cases, that is, those presumed to have non-human exposures as a source of their infections, continue to be older and are more likely to be male than secondary cases.

 

While the recent report by Reusken et al. may provide a clue as to a potential source of human infection, it is important to definitively demonstrate the presence of MERS virus in camels to confirm that the virus producing the antibody response is the same as that seen in humans. It is also important to note that the study involved only camels from Oman; other species were not available for testing and as such it is premature to focus solely on camels as a potential source of infection in humans. The critical question that remains to be answered is what exposures and activities in humans place them in contact with the virus and result in infection. This question needs to be answered urgently to inform measures that will prevent transmission to humans. This study, and the demographic differences noted above in cases acquiring infection from non-human exposures, may help to guide future investigations.

 

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WHO: MERS-CoV Summary & Literature Update – July 9th

Photo Credit WHO

 

 

# 7464

 

Although no one really knows whether MERS-CoV (or H7N9, for that matter) will turn into the next big global health threat, experts are clearly concerned and are taking prudent steps to prepare in case that should happen. 

 

A few recent examples:

 

• We’ve seen a steady flow of new guidance documents on both threats coming from the WHO, ECDC, CDC, and others over the past couple of months (see here, here, and here). 
• On Thursday the Director of NIOSH will hold a special webinar on Infection Control issues with MERS-CoV (see NIOSH Webinar: MERS-CoV Infection Prevention & Control).
• And today World Health Organization has convened an emergency meeting of international health experts to review the coronavirus threat (see WHO On The MERS-CoV Emergency Committee Meeting).

 

We should get some idea of the committee’s assessment later this week, but in the meantime the World Health Organization has posted the following summary and literature Update – dated July 9th – on this emerging coronavirus.

 

The entire report is worth reading, but the `money quote’ can be found in the summary assessment, near the end:

 

The recent mild and asymptomatic cases raise concerns about the possibility of large numbers of milder cases going undetected. While it is clear that human-to-human transmission does occur, it is not clear whether transmission is sustained in the community.

 

Obviously, this is the $64 question that needs to be answered.    

 

This summary also indicates that we can expect additional guidance from WHO for travelers to the Middle East for Umrah and the Hajj, and for infection control measures to be taken in homes, and in healthcare facilities, where cases may be present.  

 

 

 

MERS-CoV summary and literature update – as of 09 July 2013

Since April 2012, 80 laboratory-confirmed cases of human infection with Middle East respiratory syndrome coronavirus (MERS-CoV) have been reported to WHO. Forty-five of the confirmed cases have died (56%). Forty-nine of 75 cases (65%) for which the sex is known were male and the median age of the cases with known age is 51 years (range, 14 months to 94 years). Affected countries in the Middle East include Jordan, Qatar, Saudi Arabia and the United Arab Emirates (UAE); in Europe countries affected include France, Germany, the United Kingdom (UK) and Italy; and in North Africa, Tunisia. No new countries have reported MERS-CoV cases since the last update. All the European and North African cases have had a direct or indirect connection to the Middle East. However, in France, Italy, Tunisia and UK, there has been limited local transmission among close contacts that had not been to the Middle East.

 

Since the last update, 16 new laboratory-confirmed cases of MERS-CoV were reported by Saudi Arabia. Eight of the new cases were reported to be asymptomatic. Of the eight asymptomatic cases four were female health care workers, two from the Ta’if governorate and two from the Eastern Province of Saudi Arabia. The other four asymptomatic cases were children aged 7 to 15 years from Riyadh and the Eastern Province of Saudi Arabia who had contact with confirmed cases. For further details regarding the cases see Disease Outbreak News.

 

WHO MERS-CoV related activities and upcoming guidance

WHO is currently preparing travel and health advice for travellers to forthcoming mass gatherings.

 

Recommendations for infection prevention and control for MERS-CoV patients in hospital are under review. Advice on infection prevention for patients being cared for at home is under development.

 

WHO is convening an Emergency Committee meeting, as described in the International Health Regulations (2005), to review the current MERS-CoV outbreak, discuss whether the outbreak constitutes a Public Health Emergency of International Concern (PHEIC), and advise the Director General on temporary recommendations for any necessary public health actions.

 

WHO is also coordinating the collection of a panel of clinical serum specimens, which will include both MERS-CoV positive and negative specimens, to standardize serological assays. This activity is being done in collaboration with an international network of public health and research laboratories.

 

Recent guidelines

On 5 July, WHO published a guideline for investigation of MERS-CoV cases. It provides recommendations for early case investigation including further case finding, surveillance enhancements, and studies that need to be done around new cases.

 

On 3 July, WHO published revised case definitions for MERS-CoV confirmed and probable cases based on new epidemiological and clinical information. The document also contains recommendations on further evaluation for cases with inconclusive tests and asymptomatic infections.

 

On 27 June, WHO published interim surveillance recommendations for human infection with MERS-CoV. The two major changes include a stronger recommendation for the use of lower respiratory tract specimens in addition to nasopharyngeal swabs for diagnostic testing and a longer observation period for contacts of cases.

Recent papers in the scientific literature

Several MERS-CoV scientific investigations have been published in journals:

- The Saudi Arabian Ministry of Health provided an in-depth analysis of 25 (23 confirmed and 2 probable) MERS-CoV cases associated with an outbreak in Al-Hasa region of Saudi Arabia. The outbreak involved patients, their family members and health care workers from four different hospitals, including a haemodialysis unit, an intensive care unit and other inpatient units. Human-to-human-transmission was considered the likely source of infection for most of the cases. The estimated median incubation period was 5.2 days (95% confidence interval 1.9 to 14.7 days).
Reference: Assiri A et al. Hospital outbreak of Middle East Respiratory Syndrome coronavirus. New England Journal of Medecine. Published online 19 June 2013. DOI: 10.1056/NEJMoa1306742 http://www.nejm.org/doi/pdf/10.1056/NEJMoa1306742

 

- German investigators published a viral load profile of a patient infected with MERS-CoV treated in Germany in March 2013. They found very high viral loads in lower respiratory tract samples from the patient compared with upper respiratory samples, and low concentrations of the virus in stool, urine and blood.
Reference: Drosten C et al. Clinical features and virological analysis of a case of Middle East respiratory syndrome coronavirus infection. Lancet. Published Online 17 June 2013. http://dx.doi.org/10.1016/S1473-3099(13)70154-3

- A recent paper describes three possible transmission scenarios for MERS-CoV, detailing the implications for risk assessment and control for each. The scenarios include subcritical outbreaks where the reproduction number (R0) is less than 1, supercritical outbreaks where R0 is greater than 1 but the epidemic has not become self-sustaining in human populations, and a self-sustaining epidemic where R0 is greater than one. The authors stress the importance of adequate data collection in order to permit rigorous assessment of the severity and transmission characteristics of MERS-CoV.
Reference: Cauchemez S et al. Transmission scenarios for Middle East Respiratory Syndrome Coronavirus (MERS-CoV) and how to tell them apart. Euro Surveillance. Published online 13 June 2013. http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20503

Summary assessment

With recent reports of asymptomatic and mild cases, the proportion of confirmed cases that have died of MERS-CoV infections is lower than previously reported, as is the average age, and the proportion of patients who are female has increased. It is noteworthy that these cases have been detected as part of contact investigations around severe cases. These severe cases were discovered as a result of surveillance activities that focus on finding severely affected patients. Index cases, the first cases occurring in a cluster, presumably are more likely to have had a non-human exposure as their source of infection and continue to be predominantly older males, perhaps providing a clue to the exposure that resulted in their infection. Whether the relative mildness of illness in contact cases is an artifact of surveillance and case-finding activities or represents a difference in virulence between sporadic infections acquired from non-human exposures and those acquired from human-to-human transmission is unknown.

The recent mild and asymptomatic cases raise concerns about the possibility of large numbers of milder cases going undetected. While it is clear that human-to-human transmission does occur, it is not clear whether transmission is sustained in the community. The currently observed pattern of disease occurrence could be consistent either with ongoing transmission in an animal reservoir with sporadic spillover into humans resulting in non-sustained clusters, or unrecognized sustained transmission among humans with occasional severe cases. Detailed case contact investigations, increased surveillance in other countries of the region, and formal studies of non-human exposures of index cases are urgently needed to answer these questions. A new guideline for these case investigations has recently been published (see above).

The public health importance of asymptomatic cases is uncertain. More information is needed about the virus excretion patterns in persons without symptoms to understand the risk they may pose to non-infected persons. Experience from the Severe Acute Respiratory Syndrome (SARS) outbreak in 2003 suggests that very little if any transmission occurred from asymptomatic individuals. In addition, in the absence of symptomatic illness, the burden of proof must be higher because of the possibility of misclassification from false positive tests that result from laboratory contamination. In most viral infections, an immunological response, such as development of specific antibodies, would be expected even with mild or asymptomatic infection; as such, serological testing may be useful as additional confirmation of the diagnosis. Additional steps to reconfirm asymptomatic cases, or any case in which the diagnosis is suspect, could also include re-extraction of RNA from the original clinical specimen and testing for different virus target genes, ideally in an independent laboratory.
http://www.who.int/csr/disease/coronavirus_infections/LaboratoryTestingNovelCoronavirus_21Dec12.pdf

WHO continues to request that Member States report all confirmed and probable cases along with information about their exposures, testing, and clinical course to inform the most effective international preparedness and response. WHO strongly recommends detailed case investigations for every case, case-control-studies for index cases and intensive follow up of contacts with serological testing to improve knowledge of critical features of the MERS-CoV infection.

 

WHO: MERS-CoV Summary – June 20th

 

Coronavirus – Credit CDC PHIL

 

# 7415

 

Coinciding with this week’s MERS-CoV Meeting in Cairo (see WHO: Health Officials Meet In Cairo Over MERS-CoV), the World Health Organization has released a summary of what has been learned over the past few weeks about this virus.

 

 

MERS-CoV summary and literature update – as of 20 June 2013

Since April 2012, there have been 64 laboratory-confirmed cases of human infection with Middle East respiratory syndrome coronavirus (MERS-CoV); 72% have been male. Thirty-eight of the confirmed cases have died. Affected countries in the Middle East include Jordan, Saudi Arabia, the United Arab Emirates (UAE), and Qatar. Cases have also been reported by four countries in Europe, France, Germany, the United Kingdom (UK) and Italy, and by one country in North Africa, Tunisia. All of the European and North African cases have had a direct or indirect connection to the Middle East. However, in France, the UK, Tunisia and Italy, there has been limited local transmission among close contacts who had not been to the Middle East.

 

Among the new laboratory-confirmed cases of MERS-CoV reported since the last update on 31 May 2013, three have been reported by Italy. In this cluster, the index case, a 45-year-old Italian resident, travelled to Amman, Jordan in mid-April. He developed mild respiratory symptoms one day before returning home to Italy in late May. He was admitted to hospital with pneumonia 3 days after returning home. Nasopharyngeal (NP) and throat swabs taken on the day following admission were positive for MERS-CoV. He had no underlying chronic medical conditions, but was noted to be obese. He recovered and was discharged home after a week in hospital. Contact monitoring was conducted in Italy, and two developed respiratory symptoms: a 42-year-old co-worker and a 14-month-old close relative. Both tested positive for MERS-CoV. The two contacts had each been exposed to the 45-year-old man on a single day, and their illnesses began 3 and 4 days, respectively, after that exposure. Both had mild illnesses and recovered uneventfully. Follow up was also done on close contacts in Amman, Jordan. Four symptomatic and six asymptomatic contacts had NP swabs collected for testing; all were negative for MERS-COV.

 

The Ministry of Health in Saudi Arabia has also notified WHO of additional laboratory-confirmed cases of MERS-CoV with onset in late May and early June. These include cases from the Ta’if Governorate, Wadi Al-Dawaser, and Hafar Al-Batin; the first reported from these areas. The more recent cases were similar in age and sex to previously reported cases, except for a 2-year-old with chronic pulmonary disease from Jeddah.

 

 

Although the exact timing and nature of exposures that result in infection is usually unknown, for those cases for which exposure is known or strongly suspected, the incubation period for laboratory confirmed cases of MERS-CoV is generally less than one week. However, in at least one case the known exposure occurred 9 to 12 days prior to onset of illness. Further evidence in cases exposed over a range of time suggests that, at least in a minority of cases, the incubation period may exceed one week but is less than two weeks.

 

Evidence is also accumulating to suggest that nasopharyngeal swabs are less sensitive for detecting infection with MERS-CoV than specimens taken from the lower respiratory track. Currently, no head-to-head comparisons are available on the two approaches to diagnosis. However, in a number of patients, NP swabs have been negative at one point during the course of illness while lower respiratory specimens were positive at another time during the same illness. In addition, in several clusters, patients who were strongly suspected of having MERS-CoV infection because of direct exposure and severe respiratory illness had NP swabs that tested negative, while other confirmed cases in the cluster had lower respiratory track specimens that tested positive.

 

Recent papers/guidelines published since the last update

 

On 5 June 2013, WHO published updated guidance on travel recommendations for MERS-CoV (http://www.who.int/ith/updates/20130605/en/index.html). The document does not provide specific guidance for preventing MERS-CoV infection as the source of the virus is still unknown. However, it does provide general infection prevention recommendations for travelers along with recommendations for clinicians who care for travelers returning from the affected area who develop respiratory illness.

Summary assessment

The newest cases reported indicate that the source of infection, which has still not been determined, remains active in the Middle East and is present throughout a large area, including new regions in Saudi Arabia. The Italian case with history of travel to Jordan, suggests the continued risk of infection within Jordan, where no confirmed cases have been identified over 1 year despite ongoing surveillance. This cluster also represents the first time that a co-worker has become infected in a work setting other than a health care facility.

 

Two recent cases also represent the first documentation of infection in children, although one previously unconfirmed probable infection occurred in a Saudi teenager. While the virus continues to infect predominantly those who are middle aged or older, this demonstrates that children are also at risk of contracting MERS-CoV. In the two confirmed cases in children and the previous probable case, the illness was relatively mild.

 

WHO is currently reviewing surveillance recommendations based on recent observations that the incubation period may exceed 10 days in some patients. In addition, WHO now strongly recommends the collection of lower respiratory specimens such as sputum, endotracheal aspirate or bronchoalveolar lavage for diagnostic polymerase chain reaction (PCR) when possible. If initial testing of a nasopharyngeal swab is negative in a patient strongly suspected to have MERS-CoV infection, patients should be retested using a lower respiratory specimen or a repeat upper respiratory specimen with an additional oropharyngeal specimen if lower respiratory specimens are not possible. The addition of acute and convalescent serology should be considered as an additional diagnostic test when results of PCR testing of respiratory specimens are inconclusive.

 

As reported in previous updates, human-to-human transmission has not been observed to persist beyond small clusters of individuals with close contact. However, it is likely that more sporadic cases with subsequent limited transmission will occur in the near future. The large number of cases with reported co-morbidities suggests that persons with underlying medical conditions may have increased susceptibility to infection. Health care facilities dealing with patients suspected of being infected with MERS-CoV should exercise appropriate infection control measures. Clinicians should be aware that MERS-CoV infection may present atypically, and initially without respiratory symptoms, in immunocompromised individuals.

 

WHO continues to request that Member States report all confirmed and probable cases along with information about their exposures, testing, and clinical course to inform the most effective international preparedness and response.