2015 MERS outbreak in Korea: hospital-to-hospital transmission

Reported Direct and Indirect Contact with Dromedary Camels among Laboratory-Confirmed MERS-CoV Cases

Dromedary camels (Camelus dromedarius) are now known to be the vertebrate animal reservoir that intermittently transmits the Middle East respiratory syndrome coronavirus (MERS-CoV) to humans. Yet, details as to the specific mechanism(s) of zoonotic transmission from dromedaries to humans remain unclear. The aim of this study was to describe direct and indirect contact with dromedaries among all cases, and then separately for primary, non-primary, and unclassified cases of laboratory-confirmed MERS-CoV reported to the World Health Organization (WHO) between 1 January 2015 and 13 April 2018. We present any reported dromedary contact: direct, indirect, and type of indirect contact. Of all 1125 laboratory-confirmed MERS-CoV cases reported to WHO during the time period, there were 348 (30.9%) primary cases, 455 (40.4%) non-primary cases, and 322 (28.6%) unclassified cases. Among primary cases, 191 (54.9%) reported contact with dromedaries: 164 (47.1%) reported direct contact, 155 (44.5%) reported indirect contact. Five (1.1%) non-primary cases also reported contact with dromedaries. Overall, unpasteurized milk was the most frequent type of dromedary product consumed. Among cases for whom exposure was systematically collected and reported to WHO, contact with dromedaries or dromedary products has played an important role in zoonotic transmission.

Clinical management of respiratory syndrome in patients hospitalized for suspected Middle East respiratory syndrome coronavirus infection in the Paris area from 2013 to 2016

Background

Patients with suspected Middle East respiratory syndrome coronavirus (MERS-CoV) infection should be hospitalized in isolation wards to avoid transmission. This suspicion can also lead to medical confusion and inappropriate management of acute respiratory syndrome due to causes other than MERS-CoV.

Methods

We studied the characteristics and outcome of patients hospitalized for suspected MERS-CoV infection in the isolation wards of two referral infectious disease departments in the Paris area between January 2013 and December 2016.

Results

Of 93 adult patients (49 male (52.6%), median age 63.4 years) hospitalized, 82 out of 93 adult patients had returned from Saudi Arabia, and 74 of them were pilgrims (Hajj). Chest X-ray findings were abnormal in 72 (77%) patients. The 93 patients were negative for MERS-CoV RT-PCR, and 70 (75.2%) patients had documented infection, 47 (50.5%) viral, 22 (23.6%) bacterial and one Plasmodium falciparum malaria. Microbiological analysis identified Rhinovirus (27.9%), Influenza virus (26.8%), Legionella pneumophila (7.5%), Streptococcus pneumoniae (7.5%), and non-MERS-coronavirus (6.4%). Antibiotics were initiated in 81 (87%) cases, with two antibiotics in 63 patients (67.7%). The median duration of hospitalization and isolation was 3 days (1–33) and 24 h (8–92), respectively. Time of isolation decreased over time (P < 0.01). Two patients (2%) died.

Conclusion

The management of patients with possible MERS-CoV infection requires medical facilities with trained personnel, and rapid access to virological results. Empirical treatment with neuraminidase inhibitors and an association of antibiotics effective against S. pneumoniae and L. pneumophila are the cornerstones of the management of patients hospitalized for suspected MERS-CoV infection.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3223-5) contains supplementary material, which is available to authorized users.

Healthcare-associated infections: the hallmark of Middle East respiratory syndrome coronavirus with review of the literature

Middle East respiratory syndrome coronavirus (MERS-CoV) is capable of causing acute respiratory illness. Laboratory-confirmed MERS-CoV cases may be asymptomatic, have mild disease, or have a life-threatening infection with a high case fatality rate. There are three patterns of transmission: sporadic community cases from presumed non-human exposure, family clusters arising from contact with an infected family index case, and healthcare-acquired infections among patients and from patients to healthcare workers. Healthcare-acquired MERS infection has become a well-known characteristic of the disease and a leading means of spread. The main factors contributing to healthcare-associated outbreaks include delayed recognition, inadequate infection control measures, inadequate triaging and isolation of suspected MERS or other respiratory illness patients, crowding, and patients remaining in the emergency department for many days. A review of the literature suggests that effective control of hospital outbreaks was accomplished in most instances by the application of proper infection control procedures. Prompt recognition, isolation and management of suspected cases are key factors for prevention of the spread of MERS. Repeated assessments of infection control and monitoring of corrective measures contribute to changing the course of an outbreak. Limiting the number of contacts and hospital visits are also important factors to decrease the spread of infection.

Working experiences of nurses during the Middle East respiratory syndrome outbreak

Aims

To explore working experiences of nurses during Middle East respiratory syndrome outbreak.

Background

Since the first case of Middle East respiratory syndrome was reported on May 20, 2015 in South Korea, 186 people, including health care workers, were infected, and 36 died.

Design

A qualitative descriptive study.

Methods

Seven focus groups and 3 individual in‐depth interviews were conducted from August to December 2015. Content analysis was used.

Results

The following 4 major themes emerged: “experiencing burnout owing to the heavy workload,” “relying on personal protective equipment for safety,” “being busy with catching up with the new guidelines related to Middle East respiratory syndrome,” and “caring for suspected or infected patients with caution.” Participants experienced burnout because of the high volume of work and expressed safety concerns about being infected. Unclear and frequently changing guidelines were 1 of the common causes of confusion. Participants expressed that they need to be supported while caring for suspected or infected patients.

Conclusion

This study showed that creating a supportive and safe work environment is essential by ensuring adequate nurse staffing, supplying best‐quality personal protective equipment, and improving communication to provide the quality of care during infection outbreak.

What is already known about this topic?

Infectious disease outbreaks cause a significant level of distress and fear among nurses.

Nurses are near to patients, even when they have life‐threatening infectious diseases.

Little is known about the work experiences of nurses during the Middle East respiratory syndrome coronavirus outbreaks.

What this paper adds?

High volume of work and fear of infection appear to be the main concerns among nurses during the outbreak.

Nurses were confused about best practices because of lack of clarity of the guidelines during the outbreak. However, sharing information on the new guidelines and job‐related information via text messages using smartphones was helpful for the nurses.

Creating a supportive work environment and providing adequate training for nurses is essential.

The implications of this paper:

Nurse managers and hospital administrators should establish strategies to prevent nurses from burnout and to ensure their safety during the outbreak of infectious diseases.

Clear and consistent practice guidelines and effective communication methods among nurses should be developed.

Increasing awareness of health care workers about infectious diseases to enhance emergency preparedness is essential.

Chaperna-Mediated Assembly of Ferritin-Based Middle East Respiratory Syndrome-Coronavirus Nanoparticles

The folding of monomeric antigens and their subsequent assembly into higher ordered structures are crucial for robust and effective production of nanoparticle (NP) vaccines in a timely and reproducible manner. Despite significant advances in in silico design and structure-based assembly, most engineered NPs are refractory to soluble expression and fail to assemble as designed, presenting major challenges in the manufacturing process. The failure is due to a lack of understanding of the kinetic pathways and enabling technical platforms to ensure successful folding of the monomer antigens into regular assemblages. Capitalizing on a novel function of RNA as a molecular chaperone (chaperna: chaperone + RNA), we provide a robust protein-folding vehicle that may be implemented to NP assembly in bacterial hosts. The receptor-binding domain (RBD) of Middle East respiratory syndrome-coronavirus (MERS-CoV) was fused with the RNA-interaction domain (RID) and bacterioferritin, and expressed in Escherichia coli in a soluble form. Site-specific proteolytic removal of the RID prompted the assemblage of monomers into NPs, which was confirmed by electron microscopy and dynamic light scattering. The mutations that affected the RNA binding to RBD significantly increased the soluble aggregation into amorphous structures, reducing the overall yield of NPs of a defined size. This underscored the RNA-antigen interactions during NP assembly. The sera after mouse immunization effectively interfered with the binding of MERS-CoV RBD to the cellular receptor hDPP4. The results suggest that RNA-binding controls the overall kinetic network of the antigen folding pathway in favor of enhanced assemblage of NPs into highly regular and immunologically relevant conformations. The concentration of the ion Fe²⁺, salt, and fusion linker also contributed to the assembly in vitro, and the stability of the NPs. The kinetic "pace-keeping" role of chaperna in the super molecular assembly of antigen monomers holds promise for the development and delivery of NPs and virus-like particles as recombinant vaccines and for serological detection of viral infections.

Knowledge, Perceptions, and Self-reported Performance of Hand Hygiene Among Registered Nurses at Community-based Hospitals in the Republic of Korea: A Cross-sectional Multi-center Study

Objectives

To assess the nurses’ hand hygiene (HH) knowledge, perception, attitude, and self-reported performance in small- and medium-sized hospitals after Middle East Respiratory Syndrome outbreak.

Methods

The structured questionnaire was adapted from the World Health Organization’s survey. Data were collected between June 26 and July 14, 2017.

Results

Nurses showed scores on knowledge (17.6±2.5), perception (69.3±0.8), self-reported HH performance of non-self (86.0±11.0), self-reported performance of self (88.2±11.0), and attitude (50.5±5.5). HH performance rate of non-self was Y₁=36.678+ 0.555X1 (HH performance rate of self) (adjusted R²=0.280, p<0.001). The regression model for performance was Y₄=18.302+0.247X₄₁ (peception)+0.232X₄₂ (attitude)+0.875X₄₂ (role model); coefficients were significant statistically except attitude, and this model significant statistically (adjusted R²=0.191, p<0.001).

Conclusions

Advanced HH education program would be developed and operated continuously. Perception, attitude, role model was found to be a significant predictors of HH performance of self. So these findings could be used in future HH promotion strategies for nurses.

Hospital Outbreaks of Middle East Respiratory Syndrome, Daejeon, South Korea, 2015

From May through July 2015, a total of 26 cases of Middle East Respiratory Syndrome were reported from 2 hospitals in Daejeon, South Korea, including 1 index case and 25 new cases. We examined the epidemiologic features of these cases and found an estimated median incubation period of 6.1 days (8.8 days in hospital A and 4.6 days in hospital B). The overall attack rate was 3.7% (4.7% in hospital A and 3.0% in hospital B), and the attack rates among inpatients and caregivers in the same ward were 12.3% and 22.5%, respectively. The overall case-fatality rate was 44.0% (28.6% in hospital A and 63.6% in hospital B). The use of cohort quarantine may have played a role in preventing community spread, but additional transmission occurred among members of the hospital cohort quarantined together. Caregivers may have contributed in part to the transmission.

Network Analysis of MERS Coronavirus within Households, Communities, and Hospitals to Identify Most Centralized and Super-Spreading in the Arabian Peninsula, 2012 to 2016

Contact history is crucial during an infectious disease outbreak and vital when seeking to understand and predict the spread of infectious diseases in human populations. The transmission connectivity networks of people infected with highly contagious Middle East respiratory syndrome coronavirus (MERS-CoV) in Saudi Arabia were assessed to identify super-spreading events among the infected patients between 2012 and 2016. Of the 1379 MERS cases recorded during the study period, 321 (23.3%) cases were linked to hospital infection, out of which 203 (14.7%) cases occurred among healthcare workers. There were 1113 isolated cases while the number of recorded contacts per MERS patient is between 1 (n=210) and 17 (n=1), with a mean of 0.27 (SD = 0.76). Five super-important nodes were identified based on their high number of connected contacts worthy of prioritization (at least degree of 5). The number of secondary cases in each SSE varies (range, 5–17). The eigenvector centrality was significantly (p < 0.05) associated with place of exposure, with hospitals having on average significantly higher eigenvector centrality than other places of exposure. Results suggested that being a healthcare worker has a higher eigenvector centrality score on average than being nonhealthcare workers. Pathogenic droplets are easily transmitted within a confined area of hospitals; therefore, control measures should be put in place to curtail the number of hospital visitors and movements of nonessential staff within the healthcare facility with MERS cases.

MERS transmission and risk factors: a systematic review

Background

Since Middle East respiratory syndrome (MERS) infection was first reported in 2012, many studies have analysed its transmissibility and severity. However, the methodology and results of these studies have varied, and there has been no systematic review of MERS. This study reviews the characteristics and associated risk factors of MERS.

Method

We searched international (PubMed, ScienceDirect, Cochrane) and Korean databases (DBpia, KISS) for English- or Korean-language articles using the terms “MERS” and “Middle East respiratory syndrome”. Only human studies with > 20 participants were analysed to exclude studies with low representation. Epidemiologic studies with information on transmissibility and severity of MERS as well as studies containing MERS risk factors were included.

Result

A total of 59 studies were included. Most studies from Saudi Arabia reported higher mortality (22–69.2%) than those from South Korea (20.4%). While the R₀ value in Saudi Arabia was < 1 in all but one study, in South Korea, the R₀ value was 2.5–8.09 in the early stage and decreased to < 1 in the later stage. The incubation period was 4.5–5.2 days in Saudi Arabia and 6–7.8 days in South Korea. Duration from onset was 4–10 days to confirmation, 2.9–5.3 days to hospitalization, 11–17 days to death, and 14–20 days to discharge. Older age and concomitant disease were the most common factors related to MERS infection, severity, and mortality.

Conclusion

The transmissibility and severity of MERS differed by outbreak region and patient characteristics. Further studies assessing the risk of MERS should consider these factors.

MERS transmission and risk factors: a systematic review

BACKGROUND

Since Middle East respiratory syndrome (MERS) infection was first reported in 2012, many studies have analysed its transmissibility and severity. However, the methodology and results of these studies have varied, and there has been no systematic review of MERS. This study reviews the characteristics and associated risk factors of MERS.

METHOD

We searched international (PubMed, ScienceDirect, Cochrane) and Korean databases (DBpia, KISS) for English- or Korean-language articles using the terms "MERS" and "Middle East respiratory syndrome". Only human studies with > 20 participants were analysed to exclude studies with low representation. Epidemiologic studies with information on transmissibility and severity of MERS as well as studies containing MERS risk factors were included.

RESULT

A total of 59 studies were included. Most studies from Saudi Arabia reported higher mortality (22-69.2%) than those from South Korea (20.4%). While the R₀ value in Saudi Arabia was < 1 in all but one study, in South Korea, the R₀ value was 2.5-8.09 in the early stage and decreased to < 1 in the later stage. The incubation period was 4.5-5.2 days in Saudi Arabia and 6-7.8 days in South Korea. Duration from onset was 4-10 days to confirmation, 2.9-5.3 days to hospitalization, 11-17 days to death, and 14-20 days to discharge. Older age and concomitant disease were the most common factors related to MERS infection, severity, and mortality.

CONCLUSION

The transmissibility and severity of MERS differed by outbreak region and patient characteristics. Further studies assessing the risk of MERS should consider these factors.

Provision of oral hygiene services as a potential method for preventing periodontal disease and control hypertension and diabetes in a community health centre in Korea

This study aimed to evaluate the effects of a community-based oral hygiene service on general and periodontal health indicators of patients with hypertension and type 2 diabetes mellitus visiting a community health centre in Korea. The study used a one-group pretest-posttest and interrupted time-series design. A total of 151 participants (45% male), with a mean age of 63 ± 8.4 years, were included in the study; these included patients with hypertension (62%), diabetes (12%) and both hypertension and diabetes (26%). Two dental hygienists dedicated 2 days per week to this project, providing oral hygiene services to 10-13 participants per day. Four oral hygiene service sessions were provided per patient. The objective oral hygiene status and subjective self-reported periodontal status were compared before and after the service. The changes in blood pressure and glycosylated haemoglobin levels were also assessed. A lower frequency of subjective swelling was reported at the fourth session (37.9%) compared to the first (55.6%) session. Further, significantly fewer cases of calculus and bleeding were observed (p < .05), and significantly more patients reported having no gum problems at the fourth session (43.1% vs. 27.2%; p < .05) than at the first session. Finally, the participants maintained stable blood pressures at each of the four sessions, and their glycosylated haemoglobin levels were significantly lower at the fourth session. In conclusion, the findings of this study suggest that community oral hygiene services provided by dental hygienists can promote objective oral hygiene and subjective periodontal status in the local community, and may help in the control of hypertension and diabetes.

Asymptomatic Middle East Respiratory Syndrome coronavirus infection using a serologic survey in Korea

OBJECTIVES

The rates of asymptomatic infection with Middle East Respiratory Syndrome (MERS) coronavirus vary. A serologic study was conducted to determine the asymptomatic MERS infection rate in healthcare workers and non-healthcare workers by exposure status.

METHODS

Study participants were selected from contacts of MERS patients based on a priority system in 4 regions strongly affected by the 2015 MERS outbreak. A sero-epidemiological survey was performed in 1,610 contacts (average duration from exposure to test, 4.8 months), and the collected sera were tested using an enzyme-linked immunespecific assay (ELISA), immunofluorescence assay (IFA), and plaque reduction neutralization antibody test (PRNT). Among the 1,610 contacts, there were 7 ELISA-positive cases, of which 1 exhibited positive IFA and PRNT results.

RESULTS

The asymptomatic infection rate was 0.060% (95% confidence interval, 0.002 to 0.346). The asymptomatic MERS case was a patient who had been hospitalized with patient zero on the same floor of the hospital at the same time. The case was quarantined at home for 2 weeks after discharge, and had underlying diseases, including hypertension, angina, and degenerative arthritis.

CONCLUSIONS

The asymptomatic infection was acquired via healthcare-associated transmission. Thus, it is necessary to extend serologic studies to include inpatient contacts who have no symptoms.

A Middle East respiratory syndrome screening clinic for health care personnel during the 2015 Middle East respiratory syndrome outbreak in South Korea: A single-center experience

BACKGROUND

Transmission of Middle East respiratory syndrome (MERS) to health care personnel (HCP) is a major concern. This study aimed to review cases of MERS-related events, such as development of MERS-like symptoms or exposure to patients.

METHODS

A MERS screening clinic (MSC) for HCP was setup in the National Medical Center during the MERS outbreak in 2015. Clinical and laboratory data from HCP who visited the MSC were retrospectively reviewed. Additionally, these data were compared with the results of postoutbreak questionnaire surveys and interviews about MERS-related symptoms and risk-related events.

RESULTS

Of the 333 HCP who participated in MERS patient care, 35 HCP (10.5%) visited the MSC for MERS-like symptoms. No one was infected with MERS, and the most common symptom was fever (68.6%) followed by cough (34.3%). However, 106 of 285 postoutbreak survey participants experienced at least 1 MERS-related symptom and 26 reported exposure to patients without appropriate personal protective equipment, whereas only 4 HCP visited the MSC to report exposure events.

CONCLUSIONS

Although a considerable number of HCP experienced MERS-related symptoms or unprotected exposure during MERS patient care, some did not take appropriate action. These findings imply that for infection control strategy to be properly performed, education should be strengthened so that HCP can accurately recognize the risk situation and properly notify the infection control officer.

Middle East respiratory syndrome: what we learned from the 2015 outbreak in the Republic of Korea

Middle East Respiratory Syndrome coronavirus (MERS-CoV) was first isolated from a patient with severe pneumonia in 2012. The 2015 Korea outbreak of MERSCoV involved 186 cases, including 38 fatalities. A total of 83% of transmission events were due to five superspreaders, and 44% of the 186 MERS cases were the patients who had been exposed in nosocomial transmission at 16 hospitals. The epidemic lasted for 2 months and the government quarantined 16,993 individuals for 14 days to control the outbreak. This outbreak provides a unique opportunity to fill the gap in our knowledge of MERS-CoV infection. Therefore, in this paper, we review the literature on epidemiology, virology, clinical features, and prevention of MERS-CoV, which were acquired from the 2015 Korea outbreak of MERSCoV.

Role of viral bioaerosols in nosocomial infections and measures for prevention and control

The presence of patients with diverse pathologies in hospitals results in an environment that can be rich in various microorganisms including respiratory and enteric viruses, leading to outbreaks in hospitals or spillover infections to the community. All hospital patients are at risk of nosocomial viral infections, but vulnerable groups such as older adults, children and immuno-compromised/-suppressed patients are at particular risk of severe outcomes including prolonged hospitalization or death. These pathogens could transmit through direct or indirect physical contact, droplets or aerosols, with increasing evidence suggesting the importance of aerosol transmission in nosocomial infections of respiratory and enteric viruses. Factors affecting the propensity to transmit and the severity of disease transmitted via the aerosol route include the biological characteristics affecting infectivity of the viruses and susceptibility of the host, the physical properties of aerosol particles, and the environmental stresses that alter these properties such as temperature and humidity. Non-specific systematic and individual-based interventions designed to mitigate the aerosol route are available although empirical evidence of their effectiveness in controlling transmission of respiratory and enteric viruses in healthcare settings are sparse. The relative importance of aerosol transmission in healthcare setting is still an on-going debate, with particular challenge being the recovery of infectious viral bioaerosols from real-life settings and the difficulty in delineating transmission events that may also be a result of other modes of transmission. For the prevention and control of nosocomial infections via the aerosol route, more research is needed on identifying settings, medical procedures or equipment that may be associated with an increased risk of aerosol transmission, including defining which procedures are aerosol-generating; and on the effectiveness of systematic interventions on aerosol transmission of respiratory and enteric viruses in healthcare settings.

Public preferences for interventions to prevent emerging infectious disease threats: a discrete choice experiment

OBJECTIVE

When faced with an emergent epidemic with high mortality and morbidity potential, policy makers must decide what public health interventions to deploy at different stages of the outbreak. However, almost nothing is known about how the public view these interventions or how they trade off risks (of disease) with inconvenience (of interventions). In this paper, we aim to understand public perceptions on pandemic interventions, as well as to identify if there are any distinct respondent preference classes.

DESIGN

A discrete choice experiment.

SETTING

This study was fielded in Singapore between November 2012 and February 2013.

PARTICIPANTS

A random sample of 500 Singapore residents aged 21 and over, including 271 women and 229 men, was analysed.

OUTCOME MEASURES

Demographic information was collected from each participant. Participants were also shown a series of pairs of alternatives, each combining interventions and morbidity, mortality and cost outcomes and declared a preference for one combination. A random utility model was developed to determine the individual's preference for interventions and a hierarchical cluster analysis was performed to identify distinct respondent preference classes.

RESULTS

On average, participants preferred more intense interventions, and preferred scenarios with fewer deaths and lower tax. The number of infections did not significantly influence respondents' responses. We identified two broad classes of respondents: those who were mortality averse and those who were expenditure averse. Education was found to be a predictor of group membership.

CONCLUSION

Overall, there was considerable support for government interventions to prevent or mitigate outbreaks of emerging infectious diseases, including those that greatly restricted individual liberties, as long as the restrictions showed a reasonable chance of reducing the adverse health effects of the outbreak.

Contact Tracing for Imported Case of Middle East Respiratory Syndrome, China, 2015

Confirmation of an imported case of infection with Middle East respiratory syndrome coronavirus in China triggered intensive contact tracing and mandatory monitoring. Using a hotline and surveillance video footage was effective for tracing all 110 identified contacts. Contact monitoring detected no secondary transmission of infection in China.

Measles-derived vaccines to prevent emerging viral diseases

Infectious disease epidemics match wars and natural disasters in their capacity to threaten lives and damage economies. Like SARS previously and Zika recently, the Ebola crisis in 2015 showed how vulnerable the world is to these epidemics, with over 11,000 people dying in the outbreak. In addition to causing immense human suffering, these epidemics particularly affect low- and middle-income countries. Many of these deadly infectious diseases that have epidemic potential can become global health emergencies in the absence of effective vaccines. But very few vaccines against these threats have been developed to create proven medical products. The measles vaccine is an efficient, live attenuated, replicating virus that has been safely administered to 2 billion children over the last 40 years, affording life-long protection after a single dose. Taking advantage of these characteristics, this attenuated virus was transformed into a versatile chimeric or recombinant vaccine vector with demonstrated proof-of-principle in humans and a preclinical track record of rapid adaptability and effectiveness for a variety of pathogens. Clinical trials have shown the safety and immunogenicity of this vaccine platform in individuals with preexisting immunity to measles. This review describes the potential of this platform to develop new vaccines against emerging viral diseases.

Zero Transmission of Middle East Respiratory Syndrome: Lessons Learned From Thailand

New emerging pathogens can quickly become a global health threat in this era. A number of Middle East respiratory syndrome (MERS) outbreaks have been linked to healthcare facilities. The healthcare-associated transmission of Middle East respiratory syndrome coronavirus (MERS-CoV) has been attributed to overcrowding, delayed diagnosis, and the breakdown of infection control systems. Strict infection control precautions and a well-prepared hospital system may have contributed to no nosocomial transmission occurring during the treatment of MERS-CoV infections imported to Thailand. The recent outbreaks of MERS and previous emerging infections provide valuable lessons to be learned. Continuous vigilance and strengthening of infection control systems will shape the capacity to prevent and control MERS-CoV or new emerging disease transmission.

Evaluation of green tea extract as a safe personal hygiene against viral infections

Background

Viral infections often pose tremendous public health concerns as well as economic burdens. Despite the availability of vaccines or antiviral drugs, personal hygiene is considered as effective means as the first-hand measure against viral infections. The green tea catechins, in particular, epigallocatechin-3-gallate (EGCG), are known to exert potent antiviral activity. In this study, we evaluated the green tea extract as a safe personal hygiene against viral infections.

Results

Using the influenza virus A/Puerto Rico/8/34 (H1N1) as a model, we examined the duration of the viral inactivating activity of green tea extract (GTE) under prolonged storage at various temperature conditions. Even after the storage for 56 days at different temperatures, 0.1% GTE completely inactivated 10⁶ PFU of the virus (6 log₁₀ reduction), and 0.01% and 0.05% GTE resulted in 2 log₁₀ reduction of the viral titers. When supplemented with 2% citric acid, 0.1% sodium benzoate, and 0.2% ascorbic acid as anti-oxidant, the inactivating activity of GTE was temporarily compromised during earlier times of storage. However, the antiviral activity of the GTE was steadily recovered up to similar levels with those of the same concentrations of GTE without the supplements, effectively prolonging the duration of the virucidal function over extended period. Cryo-EM and DLS analyses showed a slight increase in the overall size of virus particles by GTE treatment. The results suggest that the virucidal activity of GTE is mediated by oxidative crosslinking of catechins to the viral proteins and the change of physical properties of viral membranes.

Conclusions

The durability of antiviral effects of GTE was examined as solution type and powder types over extended periods at various temperature conditions using human influenza A/H1N1 virus. GTE with supplements demonstrated potent viral inactivating activity, resulting in greater than 4 log₁₀ reduction of viral titers even after storage for up to two months at a wide range of temperatures. These data suggest that GTE-based antiviral agents could be formulated as a safe and environmentally friendly personal hygiene against viral infections.

Toward Developing a Preventive MERS-CoV Vaccine-Report from a Workshop Organized by the Saudi Arabia Ministry of Health and the International Vaccine Institute, Riyadh, Saudi Arabia, November 14-15, 2015

Middle East respiratory syndrome (MERS) remains a serious international public health threat. With the goal of accelerating the development of countermeasures against MERS coronavirus (MERS-CoV), funding agencies, nongovernmental organizations, and researchers across the world assembled in Riyadh, Saudi Arabia, on November 14-15, 2015, to discuss vaccine development challenges. The meeting was spearheaded by the Saudi Ministry of Health and co-organized by the International Vaccine Institute, South Korea. Accelerating the development of a preventive vaccine requires a better understanding of MERS epidemiology, transmission, and pathogenesis in humans and animals. A combination of rodent and nonhuman primate models should be considered in evaluating and developing preventive and therapeutic vaccine candidates. Dromedary camels should be considered for the development of veterinary vaccines. Several vaccine technology platforms targeting the MERS-CoV spike protein were discussed. Mechanisms to maximize investment, provide robust data, and affect public health are urgently needed.

A study of the probable transmission routes of MERS-CoV during the first hospital outbreak in the Republic of Korea

Infections caused by the Middle East respiratory syndrome coronavirus (MERS-CoV) are a serious health issue due to their prevalence and associated mortality. However, the transmission routes of the virus remain unclear, and thus, the current recommended control strategies are not evidence based. In this study, we investigated the transmission routes of MERS-CoV during the first nosocomial outbreak in the Republic of Korea in May 2015 using a multi-agent modeling framework. We identified seven hypothesized transmission modes based on the three main transmission routes (long-range airborne, close contact, and fomite). The infection risks for each hypothesis were estimated using the multi-agent modeling framework. Least-squares fitting was conducted to compare the distribution of the predicted infection risk in the various scenarios with that of the reported attack rates and to identify the hypotheses with the best fit. In the scenarios in which the index patient was a super-spreader, our model simulations suggested that MERS-CoV probably spread via the long-range airborne route. However, it is possible that the index patient shed an average viral load comparable to the loads reported in the literature, and that transmission occurred via a combined long-range airborne and close contact route.

Healthcare worker infected with Middle East Respiratory Syndrome during cardiopulmonary resuscitation in Korea, 2015

OBJECTIVES

During the outbreak of the Middle East Respiratory Syndrome (MERS) in Korea in 2015, the Korea Centers for Disease Control and Prevention (KCDC) confirmed a case of MERS in a healthcare worker in Daejeon, South Korea. To verify the precise route of infection for the case, we conducted an in-depth epidemiological investigation in cooperation with the KCDC.

METHODS

We reviewed the MERS outbreak investigation report of the KCDC, and interviewed the healthcare worker who had recovered from MERS. Using the media interview data, we reaffirmed and supplemented the nature of the exposure.

RESULTS

The healthcare worker, a nurse, was infected while performing cardiopulmonary resuscitation (CPR) for a MERS patient in an isolation room. During the CPR which lasted for an hour, a large amount of body fluid was splashed. The nurse was presumed to have touched the mask to adjust its position during the CPR. She suggested that she was contaminated with the MERS patient's body fluids by wiping away the sweat from her face during the CPR.

CONCLUSIONS

The possible routes of infection may include the following: respiratory invasion of aerosols contaminated with MERS-coronavirus (MERS-CoV) through a gap between the face and mask; mucosal exposure to sweat contaminated with MERS-CoV; and contamination during doffing of personal protective equipment. The MERS guidelines should reflect this case to decrease the risk of infection during CPR.

The Impact of Middle East Respiratory Syndrome Outbreak on Trends in Emergency Department Utilization Patterns

Changes occurred in the patterns of utilization of emergency medical services during the Middle East respiratory syndrome (MERS) outbreak. The purpose of this study was to analyze the patterns of adult and pediatric patients who visited the emergency department (ED) during the outbreak. This retrospective study was conducted by analyzing changes in the patterns of visits among adult and pediatric patients in the ED at one tertiary teaching hospital in Korea. The study was performed from June 1, 2013 to July 31, 2015. The MERS outbreak period was from June 1 to July 31, 2015, and we compared that period to the same periods in 2013 and 2014. We compared and analyzed the patients' characteristics, emergency severity index (ESI) level at the visit, cause of visit, diagnosis, final dispositions, injury/non-injury, length of stay at the ED (EDLOS), and hospitalization rate. A total of 9,107 patients visited the ED during this period. Of these patients, 2,572 (28.2%) were pediatric patients and 6,535 (71.8%) were adult patients. The most common cause of an ED visit was fever (adult patients: 21.6%, pediatric patients: 56.2%). The proportion of non-urgent visits involving an ESI level of 4 or 5 and the EDLOS decreased significantly in pediatric and adult patients in comparison to that during the past two years. This change was significant in pediatric patients. Among adult patients, the rate of injury decreased, whereas it increased among pediatric patients. During the MERS outbreak period, pediatric ED visits due to non-urgent cases decreased significantly and there were more pronounced differences in ED utilization patterns in pediatric patients than in adult patients.

MERS-CoV Infection in a Pregnant Woman in Korea

Middle East respiratory syndrome (MERS) is a lethal respiratory disease - caused by MERS-coronavirus (MERS-CoV) which was first identified in 2012. Especially, pregnant women can be expected as highly vulnerable candidates for this viral infection. In May 2015, this virus was spread in Korea and a pregnant woman was confirmed with positive result of MERS-CoV polymerase chain reaction (PCR). Her condition was improved only with conservative treatment. After a full recovery of MERS, the patient manifested abrupt vaginal bleeding with rupture of membrane. Under an impression of placenta abruption, an emergent cesarean section was performed. Our team performed many laboratory tests related to MERS-CoV and all results were negative. We report the first case of MERS-CoV infection during pregnancy occurred outside of the Middle East. Also, this case showed relatively benign maternal course which resulted in full recovery with subsequent healthy full-term delivery without MERS-CoV transmission.

High reproduction number of Middle East respiratory syndrome coronavirus in nosocomial outbreaks: mathematical modelling in Saudi Arabia and South Korea

Background

Effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (R₀). R₀ for severe acute respiratory syndrome is generally considered to be >1, whereas that for Middle East respiratory syndrome (MERS) is considered to be <1. However, this does not explain the large-scale outbreaks of MERS that occurred in Kingdom of Saudi Arabia (KSA) and South Korean hospitals.

Aim: To estimate R₀ in nosocomial outbreaks of MERS.

Methods

R₀ was estimated using the incidence decay with an exponential adjustment model. The KSA and Korean outbreaks were compared using a line listing of MERS cases compiled using publicly available sources. Serial intervals to estimate R₀ were assumed to be six to eight days. Study parameters [R₀ and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using Matlab.

Findings

The estimated R₀ in Korea was 3.9 in the best-fit model, with a serial interval of six days. The first outbreak cluster in a hospital in Pyeongtaek had an R₀ of 4.04, and the largest outbreak cluster in a hospital in Samsung had an R₀ of 5.0. Assuming a six-day serial interval, the KSA outbreaks in Jeddah and Riyadh had R₀ values of 3.9 and 1.9, respectively.

Conclusion

R₀ for the nosocomial MERS outbreaks in KSA and South Korea was estimated to be in the range of 2–5, which is significantly higher than the previous estimate of <1. Therefore, more comprehensive countermeasures are needed to address these infections.

Immunogenicity and structures of a rationally designed prefusion MERS-CoV spike antigen

Middle East respiratory syndrome coronavirus (MERS-CoV) is a lineage C betacoronavirus that since its emergence in 2012 has caused outbreaks in human populations with case-fatality rates of ∼36%. As in other coronaviruses, the spike (S) glycoprotein of MERS-CoV mediates receptor recognition and membrane fusion and is the primary target of the humoral immune response during infection. Here we use structure-based design to develop a generalizable strategy for retaining coronavirus S proteins in the antigenically optimal prefusion conformation and demonstrate that our engineered immunogen is able to elicit high neutralizing antibody titers against MERS-CoV. We also determined high-resolution structures of the trimeric MERS-CoV S ectodomain in complex with G4, a stem-directed neutralizing antibody. The structures reveal that G4 recognizes a glycosylated loop that is variable among coronaviruses and they define four conformational states of the trimer wherein each receptor-binding domain is either tightly packed at the membrane-distal apex or rotated into a receptor-accessible conformation. Our studies suggest a potential mechanism for fusion initiation through sequential receptor-binding events and provide a foundation for the structure-based design of coronavirus vaccines.

Exploring Nursing Intention, Stress, and Professionalism in Response to Infectious Disease Emergencies: The Experience of Local Public Hospital Nurses During the 2015 MERS Outbreak in South Korea

Purpose

This study aimed to examine levels of stress and professionalism of nurses who provided nursing care during the 2015 Middle East respiratory syndrome outbreak based on their experience, to investigate the nurses' intention to respond to possible future outbreaks in relation to their experience during the outbreak, and to determine the relationship between the outbreak experience and nursing intention considering stress and professionalism.

Methods

A self-administered questionnaire was designed based on modifications of related questionnaires, and used to assess levels of stress, professionalism, and nursing intention according to participants' experiences during the outbreak. Multiple regression analysis was used to examine the relationship between the outbreak nursing experience and nursing intention considering stress and nursing professionalism.

Results

The overall stress, professionalism, and nursing intention scores for the firsthand experience group were 33.72, 103.00, and 16.92, respectively, whereas those of the secondhand experience group were 32.25, 98.99, and 15.60, respectively. There were significant differences in professionalism and nursing intention scores between the groups (p = .001 and p < .001, respectively). The regression analysis revealed that the regression estimate between stress and nursing intention was B(SE) = −0.08(0.02), beta = −0.21, p < .001 and the regression estimate between professionalism in nursing and nursing intention was B(SE) = 0.05(0.01), beta = 0.23, p < .001.

Conclusion

Prior outbreak nursing experience was importantly associated with intention to provide care for patients with a newly emerging infectious disease in the future considering stress and professionalism. Gathering information about nurses' experience of epidemics and regular assessment of job stress and professionalism are required.

The clinical and virological features of the first imported case causing MERS-CoV outbreak in South Korea, 2015

BACKGROUND

In 2015, the largest outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection outside the Middle East occurred in South Korea. We summarized the epidemiological, clinical, and laboratory findings of the first Korean case of MERS-CoV and analyzed whole-genome sequences of MERS-CoV derived from the patient.

CASE PRESENTATION

A 68-year-old man developed fever and myalgia 7 days after returning to Korea, following a 10-day trip to the Middle East. Before diagnosis, he visited 4 hospitals, potentially resulting in secondary transmission to 28 patients. On admission to the National Medical Center (day 9, post-onset of clinical illness), he presented with drowsiness, hypoxia, and multiple patchy infiltrations on the chest radiograph. He was intubated (day 12) because of progressive acute respiratory distress syndrome (ARDS) and INF-α2a and ribavirin treatment was commenced. The treatment course was prolonged by superimposed ventilator associated pneumonia. MERS-CoV PCR results converted to negative from day 47 and the patient was discharged (day 137), following rehabilitation therapy. The complete genome sequence obtained from a sputum sample (taken on day 11) showed the highest sequence similarity (99.59%) with the virus from an outbreak in Riyadh, Saudi Arabia, in February 2015.

CONCLUSIONS

The first case of MERS-CoV infection had high transmissibility and was associated with a severe clinical course. The patient made a successful recovery after early treatment with antiviral agents and adequate supportive care. This first case in South Korea became a super-spreader because of improper infection control measures, rather than variations of the virus.

Impact of Middle East respiratory syndrome outbreak on the use of emergency medical resources in febrile patients

OBJECTIVE

Outbreaks of transmissible respiratory infection are suspected to have significant effects on the health of pediatric and geriatric patients. The objective was to assess the impact of the Middle East respiratory syndrome (MERS) outbreak on the use of emergency resources.

METHODS

An ecologic analysis of emergency department (ED) records between September and December 2015, was performed. Data was obtained from the National Emergency Department Information System database for Korea. All demographic and diagnostic data from patients presenting with febrile symptoms as a main complaint were collected. The data were compared to the equivalent period in the three years preceding the MERS outbreak in Korea.

RESULTS

Following the MERS outbreak, there was an increase in overall ED visits by febrile patients and the proportion of visits by febrile patients, relative to total ED attendances. This effect was more prominent in the children under five years. The duration of the chief complaint before ED arrival and the length of ED stay were significantly increased among younger pediatric patients. Decreased body temperature on arrival was observed in younger pediatric patients.

CONCLUSION

MERS outbreak appears to have had a significant effects on ED use by febrile patients. The use of emergency care services by pediatric patients makes them more vulnerable to an outbreak of a transmissable disease. An effective strategy to control emergency center visits by non-urgent febrile patients and provide proper medical services is urgently needed.

MERS-CoV infection: Mind the public knowledge gap

In August 2015, the Corona outbreak caused by Middle East respiratory syndrome coronavirus (MERS-CoV) was the 9th episode since June 2012 in Saudi Arabia. Little is known about the public awareness toward the nature or prevention of the disease. The aim of this work was to assess the knowledge of the adult population in Riyadh toward the MERS-CoV.

In this cross-sectional survey, a self-administrated questionnaire was distributed to randomly selected participants visiting malls in Riyadh. The questionnaire contained measurable epidemiological and clinical MERS-CoV knowledge level variables and relevant source of information.

The study included 676 participants. Mean age was 32.5 (±SD 8.6) years and 353 (47.8%) were males. Almost all participants heard about the corona disease and causative agent. The study showed a fair overall knowledge (66.0%), less knowledge on epidemiological features of the disease (58.3%), and good knowledge (90.7%) on the clinical manifestation of the MERS-CoV. Internet was the major (89.0%) source of disease information, and other sources including health care providers, SMS, television, magazines and books were low rated (all <25%). In a multivariate logistic regression analysis age ≤30 years (Odds Ratio (OR) = 1.647, 95%CI 1.048–2.584, P = 0.030), male gender (OR = 1.536, 95%CI 1.105–2.134, P = 0.01), and no tertiary education (OR = 1.957, 95%CI 1.264–3.030, P = 0.003) were independent significant predictors of poor epidemiological knowledge.

This study concludes that there was inadequate epidemiological knowledge received by the public and the reliance mostly on the clinical manifestations to recognizing the MERS-CoV disease. Comprehensive public health education programs is important to increase awareness of simple epidemiological determinants of the disease is warranted.

A novel neutralizing monoclonal antibody targeting the N-terminal domain of the MERS-CoV spike protein

Middle East respiratory syndrome coronavirus (MERS-CoV) has caused fatal infections, some through hospital-acquired transmission, in affected regions since its emergence in 2012. Although the virus is not pandemic among humans, it poses a great threat to public health due to its zoonotic origin. Thus, both preventative and therapeutic countermeasures are urgently needed. In this study, we discovered a panel of neutralizing monoclonal antibodies (mAbs) against MERS-CoV, which mapped to a wide range of regions on the spike (S) protein of the virus. In addition to mAbs with neutralizing epitopes located on the receptor-binding domain, one mAb, 5F9, which binds to the N-terminal domain (NTD) of the MERS-CoV S1 subunit, showed efficient neutralizing activity against the wild-type MERS-CoV strain EMC/2012, with a half maximal inhibitory concentration of 0.2 μg/mL. We concluded that a novel neutralizing epitope for MERS-CoV also resides on the NTD of the S protein, indicating that the NTD might be important during the viral infection process. Our findings have significant implications for further vaccine design and for the development of prophylactic and therapeutic monoclonal immunotherapies against MERS-CoV infection.

Outcome of strict implementation of infection prevention control measures during an outbreak of Middle East respiratory syndrome

Background

The objective of this retrospective cohort study was to assess the impact of implementation of different levels of infection prevention and control (IPC) measures during an outbreak of Middle East respiratory syndrome (MERS) in a large tertiary hospital in Saudi Arabia. The setting was an emergency room (ER) in a large tertiary hospital and included primary and secondary MERS patients.

Methods

Rapid response teams conducted repeated assessments of IPC and monitored implementation of corrective measures using a detailed structured checklist. We ascertained the epidemiologic link between patients and calculated the secondary attack rate per 10,000 patients visiting the ER (SAR/10,000) in 3 phases of the outbreak.

Results

In phase I, 6 primary cases gave rise to 48 secondary cases over 4 generations, including a case that resulted in 9 cases in the first generation of secondary cases and 21 cases over a chain of 4 generations. During the second and third phases, the number of secondary cases sharply dropped to 18 cases and 1 case, respectively, from a comparable number of primary cases. The SAR/10,000 dropped from 75 (95% confidence interval [CI], 55-99) in phase I to 29 (95% CI, 17-46) and 3 (95% CI, 0-17) in phases II and III, respectively.

Conclusions

The study demonstrated salient evidence that proper institution of IPC measures during management of an outbreak of MERS could remarkably change the course of the outbreak.

Effects of operational decisions on the diffusion of epidemic disease: A system dynamics modeling of the MERS-CoV outbreak in South Korea

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Development of a macro-level health system dynamics model.

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Performance measurements of epidemic disease diffusion and patient-care performance from an operational perspective.

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Comparison of economic and optimal patient room design performance under different infectivity scenarios.

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Comparison of secondary infection outcomes under different ER occupancy circumstances.

We evaluated the nosocomial outbreak of Middle East Respiratory Syndrome (MERS) Coronavirus (CoV) in the Republic of Korea, 2015, from a healthcare operations management perspective. Establishment of healthcare policy in South Korea provides patients’ freedom to select and visit multiple hospitals. Current policy enforces hospitals preference for multi-patient rooms to single-patient rooms, to lower financial burden. Existing healthcare systems tragically contributed to 186 MERS outbreak cases, starting from single “index patient” into three generations of secondary infections. By developing a macro-level health system dynamics model, we provide empirical knowledge to examining the case from both operational and financial perspectives. In our simulation, under base infectivity scenario, high emergency room occupancy circumstance contributed to an estimated average of 101 (917%) more infected patients, compared to when in low occupancy circumstance. Economic patient room design showed an estimated 702% increase in the number of infected patients, despite the overall 98% savings in total expected costs compared to optimal room design. This study provides first time, system dynamics model, performance measurements from an operational perspective. Importantly, the intent of this study was to provide evidence to motivate public, private, and government healthcare administrators’ recognition of current shortcomings, to optimize performance as a whole system, rather than mere individual aspects.

DNA vaccine encoding Middle East respiratory syndrome coronavirus S1 protein induces protective immune responses in mice

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DNA vaccine encoding MERS-CoV S1 gene induced humoral and cellular immune responses.

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High titers of neutralizing antibodies were generated without adjuvant.

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Virus loads in lungs significantly decreased in vaccinated and serum received mice.

The Middle East respiratory syndrome coronavirus (MERS-CoV), is an emerging pathogen that continues to cause outbreaks in the Arabian peninsula and in travelers from this region, raising the concern that a global pandemic could occur. Here, we show that a DNA vaccine encoding the first 725 amino acids (S1) of MERS-CoV spike (S) protein induces antigen-specific humoral and cellular immune responses in mice. With three immunizations, high titers of neutralizing antibodies (up to 1: 10⁴) were generated without adjuvant. DNA vaccination with the MERS-CoV S1 gene markedly increased the frequencies of antigen-specific CD4⁺ and CD8⁺ T cells secreting IFN-γ and other cytokines. Both pcDNA3.1-S1 DNA vaccine immunization and passive transfer of immune serum from pcDNA3.1-S1 vaccinated mice protected Ad5-hDPP4-transduced mice from MERS-CoV challenge. These results demonstrate that a DNA vaccine encoding MERS-CoV S1 protein induces strong protective immune responses against MERS-CoV infection.

High fatality rates and associated factors in two hospital outbreaks of MERS in Daejeon, the Republic of Korea

OBJECTIVES

To explore the epidemiological and clinical factors predictive of the case fatality rate (CFR) of Middle East respiratory syndrome-coronavirus (MERS-CoV) infection in an outbreak in Daejeon, the Republic of Korea.

METHODS

We reviewed the outbreak investigation reports and medical records of 1 index case and 25 additional MERS cases in hospitals A (14 cases) and B (11 cases), and conducted an in-depth interview with the index case.

RESULTS

The CFR in hospital B was higher than that in hospital A (63.6% vs. 28.6%, respectively). Higher MERS-CoV exposure conditions were also found in hospital B, including aggravated pneumonia in the index case and nebulizer use in a six-bed admission room. The host factors associated with high CFR were pre-existing pneumonia, smoking history, an incubation period of less than 5 days, leukocytosis, abnormal renal function at diagnosis, and respiratory symptoms such as sputum and dyspnea.

CONCLUSIONS

The conditions surrounding MERS-CoV exposure and the underlying poor pulmonary function due to a smoking history or pre-existing pneumonia may explain the high CFR in hospital B. The clinical features described above may enable prediction of the prognosis of MERS cases.

Middle East Respiratory Syndrome

Between September 2012 and January 20, 2017, the World Health Organization (WHO) received reports from 27 countries of 1879 laboratory-confirmed cases in humans of the Middle East respiratory syndrome (MERS) caused by infection with the MERS coronavirus (MERS-CoV) and at least 659 related deaths. Cases of MERS-CoV infection continue to occur, including sporadic zoonotic infections in humans across the Arabian Peninsula, occasional importations and associated clusters in other regions, and outbreaks of nonsustained human-to-human transmission in health care settings. Dromedary camels are considered to be the most likely source of animal-to-human transmission. MERS-CoV enters host cells after binding the dipeptidyl peptidase 4 (DPP-4) receptor and the carcinoembryonic antigen–related cell-adhesion molecule 5 (CEACAM5) cofactor ligand, and it replicates efficiently in the human respiratory epithelium. Illness begins after an incubation period of 2 to 14 days and frequently results in hypoxemic respiratory failure and the need for multiorgan support. However, asymptomatic and mild cases also occur. Real-time reverse-transcription–polymerase-chain-reaction (RT-PCR) testing of respiratory secretions is the mainstay for diagnosis, and samples from the lower respiratory tract have the greatest yield among seriously ill patients. There is no antiviral therapy of proven efficacy, and thus treatment remains largely supportive; potential vaccines are at an early developmental stage. There are multiple gaps in knowledge regarding the evolution and transmission of the virus, disease pathogenesis, treatment, and prospects for a vaccine. The ongoing occurrence of MERS in humans and the associated high mortality call for a continued collaborative approach toward gaining a better understanding of the infection both in humans and in animals. MERS-CoV was first identified in September 2012 in a patient from Saudi Arabia who had hypoxemic respiratory failure and multiorgan illness. Subsequent cases have included infections in humans across the Arabian Peninsula, occasional importations and associated clusters in other regions, and outbreaks of nonsustained human-to-human transmission in health care settings (Fig. 1).

Effects of patients' motives in choosing a provider on determining the type of medical institution

BACKGROUND

Primary care is relatively weak in the Republic of Korea. As the referral system is not well established, patients can freely choose from among clinics, hospitals, and tertiary hospitals. This study was conducted to determine the factors influencing patients' choice of providers.

METHODS

A survey was conducted of 999 Korean adults aged 19-59 years. An exploratory factor analysis was performed on nine factors influencing their motives in choosing a medical provider. The factors derived from this analysis and the types of medical institutions were used as the independent and dependent variables, respectively, in logistic regression analysis. Adjustments were made for region, gender, age, educational level, income, type of insurance, and chronic diseases.

RESULTS

The results showed that patients preferred clinics when considering the importance of accessibility, staff kindness, and patient-centeredness; they preferred hospitals when considering cleanliness; and tertiary hospitals when considering the reputation and structural factors. When considering structural factors, clinics and hospitals were less preferred; however tertiary hospitals were less preferred when considering accessibility, staff kindness, and patient-centeredness.

CONCLUSION

It is necessary to provide more accessible and patient-centered services in order to strengthen the primary health care role of clinics. In addition, efforts are needed to improve the quality of health care of tertiary hospitals in order to meet patient expectations.

Human Coronavirus in the 2014 Winter Season as a Cause of Lower Respiratory Tract Infection

PURPOSE

During the late autumn to winter season (October to December) in the Republic of Korea, respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections (LRTIs). Interestingly, in 2014, human coronavirus (HCoV) caused not only upper respiratory infections but also LRTIs more commonly than in other years. Therefore, we sought to determine the epidemiology, clinical characteristics, outcomes, and severity of illnesses associated with HCoV infections at a single center in Korea.

MATERIALS AND METHODS

We retrospectively identified patients with positive HCoV respiratory specimens between October 2014 and December 2014 who were admitted to Severance Children's Hospital at Yonsei University Medical Center for LRTI. Charts of the patients with HCoV infection were reviewed and compared with RSV infection.

RESULTS

During the study period, HCoV was the third most common respiratory virus and accounted for 13.7% of infections. Coinfection was detected in 43.8% of children with HCoV. Interestingly, one patient had both HCoV-OC43 and HCoV-NL63. Mild pneumonia was most common (60.4%) with HCoV, and when combined with RSV, resulted in bronchiolitis. Two patients required care in the intensive care unit. However, compared with that of RSV infection, the disease course HCoV was short.

CONCLUSION

Infections caused by HCoVs are common, and can cause LRTIs. During an epidemic season, clinicians should be given special consideration thereto. When combined with other medical conditions, such as neurologic or cardiologic diseases, intensive care unit (ICU) care may be necessary.

Fatality risks for nosocomial outbreaks of Middle East respiratory syndrome coronavirus in the Middle East and South Korea

Middle East respiratory syndrome coronavirus (MERS-CoV) was first isolated in 2012. The largest known outbreak outside the Middle East occurred in South Korea in 2015. As of 29 June 2016, 1769 laboratory-confirmed cases (630 deaths; 35.6 % case fatality rate [CFR]) had been reported from 26 countries, particularly in the Middle East. However, the CFR for hospital outbreaks was higher than that of family clusters in the Middle East and Korea. Here, we compared the mortality rates for 51 nosocomial outbreaks in the Middle East and one outbreak of MERS-CoV in South Korea. Our findings showed the CFR in the Middle East was much higher than that in South Korea (25.9 % [56/216] vs. 13.8 % [24/174], p = 0.003). Infected individuals who died were, on average, older than those who survived in both the Middle East (64 years [25-98] vs. 46 years [2-85], p = 0.000) and South Korea (68 years [49-82] vs. 53.5 years [16-87], p = 0.000). Similarly, the co-morbidity rates for the fatal cases were statistically higher than for the nonfatal cases in both the Middle East (64.3 % [36/56] vs. 28.1 % [45/160], p = 0.000) and South Korea (45.8 % [11/24] vs. 12.0 % [18/150], p = 0.000). The median number of days from onset to confirmation of infection in the fatal cases was longer than that for survivors from the Middle East (8 days [1-47] vs. 4 days [0-14], p = 0.009). Thus, older age, pre-existing concurrent diseases, and delayed confirmation increase the odds of a fatal outcome in nosocomial MERS-CoV outbreaks in the Middle East and South Korea.

MERS-CoV spike protein: a key target for antivirals

INTRODUCTION

The continual Middle East respiratory syndrome (MERS) threat highlights the importance of developing effective antiviral therapeutics to prevent and treat MERS coronavirus (MERS-CoV) infection. A surface spike (S) protein guides MERS-CoV entry into host cells by binding to cellular receptor dipeptidyl peptidase-4 (DPP4), followed by fusion between virus and host cell membranes. MERS-CoV S protein represents a key target for developing therapeutics to block viral entry and inhibit membrane fusion. Areas covered: This review illustrates MERS-CoV S protein's structure and function, particularly S1 receptor-binding domain (RBD) and S2 heptad repeat 1 (HR1) as therapeutic targets, and summarizes current advancement on developing anti-MERS-CoV therapeutics, focusing on neutralizing monoclonal antibodies (mAbs) and antiviral peptides. Expert opinion: No anti-MERS-CoV therapeutic is approved for human use. Several S-targeting neutralizing mAbs and peptides have demonstrated efficacy against MERS-CoV infection, providing feasibility for development. Generally, human neutralizing mAbs targeting RBD are more potent than those targeting other regions of S protein. However, emergence of escape mutant viruses and mAb's limitations make it necessary for combining neutralizing mAbs recognizing different neutralizing epitopes and engineering them with improved efficacy and reduced cost. Optimization of the peptide sequences is expected to produce next-generation anti-MERS-CoV peptides with improved potency.

Recombinant Receptor-Binding Domains of Multiple Middle East Respiratory Syndrome Coronaviruses (MERS-CoVs) Induce Cross-Neutralizing Antibodies against Divergent Human and Camel MERS-CoVs and Antibody Escape Mutants

Middle East respiratory syndrome coronavirus (MERS-CoV) binds to cellular receptor dipeptidyl peptidase 4 (DPP4) via the spike (S) protein receptor-binding domain (RBD). The RBD contains critical neutralizing epitopes and serves as an important vaccine target. Since RBD mutations occur in different MERS-CoV isolates and antibody escape mutants, cross-neutralization of divergent MERS-CoV strains by RBD-induced antibodies remains unknown. Here, we constructed four recombinant RBD (rRBD) proteins with single or multiple mutations detected in representative human MERS-CoV strains from the 2012, 2013, 2014, and 2015 outbreaks, respectively, and one rRBD protein with multiple changes derived from camel MERS-CoV strains. Like the RBD of prototype EMC2012 (EMC-RBD), all five RBDs maintained good antigenicity and functionality, the ability to bind RBD-specific neutralizing monoclonal antibodies (MAbs) and the DPP4 receptor, and high immunogenicity, able to elicit S-specific antibodies. They induced potent neutralizing antibodies cross-neutralizing 17 MERS pseudoviruses expressing S proteins of representative human and camel MERS-CoV strains identified during the 2012-2015 outbreaks, 5 MAb escape MERS-CoV mutants, and 2 live human MERS-CoV strains. We then constructed two RBDs mutated in multiple key residues in the receptor-binding motif (RBM) of RBD and demonstrated their strong cross-reactivity with anti-EMC-RBD antibodies. These RBD mutants with diminished DPP4 binding also led to virus attenuation, suggesting that immunoevasion after RBD immunization is accompanied by loss of viral fitness. Therefore, this study demonstrates that MERS-CoV RBD is an important vaccine target able to induce highly potent and broad-spectrum neutralizing antibodies against infection by divergent circulating human and camel MERS-CoV strains.

IMPORTANCE

MERS-CoV was first identified in June 2012 and has since spread in humans and camels. Mutations in its spike (S) protein receptor-binding domain (RBD), a key vaccine target, have been identified, raising concerns over the efficacy of RBD-based MERS vaccines against circulating human and camel MERS-CoV strains. Here, we constructed five vaccine candidates, designated 2012-RBD, 2013-RBD, 2014-RBD, 2015-RBD, and Camel-RBD, containing single or multiple mutations in the RBD of representative human and camel MERS-CoV strains during the 2012-2015 outbreaks. These RBD-based vaccine candidates maintained good functionality, antigenicity, and immunogenicity, and they induced strong cross-neutralizing antibodies against infection by divergent pseudotyped and live MERS-CoV strains, as well as antibody escape MERS-CoV mutants. This study provides impetus for further development of a safe, highly effective, and broad-spectrum RBD-based subunit vaccine to prevent MERS-CoV infection.

CD8+ T Cells and Macrophages Regulate Pathogenesis in a Mouse Model of Middle East Respiratory Syndrome

Middle East respiratory syndrome coronavirus (MERS-CoV) is an important emerging pathogen that was first described in 2012. While the cell surface receptor for MERS-CoV has been identified as dipeptidyl peptidase 4 (DPP4), the mouse DPP4 homologue does not allow virus entry into cells. Therefore, development of mouse models of MERS-CoV has been hampered by the fact that MERS-CoV does not replicate in commonly available mouse strains. We have previously described a mouse model in which mDPP4 was replaced with hDPP4 such that hDPP4 is expressed under the endogenous mDPP4 promoter. In this study, we used this mouse model to analyze the host response to MERS-CoV infection using immunological assays and transcriptome analysis. Depletion of CD4⁺ T cells, CD8⁺ T cells, or macrophages has no effect on MERS-CoV replication in the lungs of infected mice. However, we found that depletion of CD8⁺ T cells protects and depletion of macrophages exacerbates MERS-CoV-induced pathology and clinical symptoms of disease. Overall, we demonstrate an important role for the inflammatory response in regulating MERS-CoV pathogenesis in vivo IMPORTANCE: The Middle East respiratory syndrome coronavirus (MERS-CoV) is a highly pathogenic respiratory virus that emerged from zoonotic sources in 2012. Human infections are still occurring throughout Saudi Arabia at a 38% case fatality rate, with the potential for worldwide spread via air travel. In this work, we identify the host response to the virus and identify inflammatory pathways and cell populations that are critical for protection from severe lung disease. By understanding the immune response to MERS-CoV we can develop targeted therapies to inhibit pathogenesis in the future.

Risk factors for transmission of Middle East respiratory syndrome coronavirus infection during the 2015 outbreak in South Korea

Background.

Transmission heterogeneity was observed during the 2015 Korean outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection. Only 22 of 186 cases transmitted the infection, and 5 super-spreading events caused 150 transmissions. We investigated the risk factors for MERS-CoV transmission.

Methods.

Epidemiological reports were used to classify patients as nonspreaders, spreaders, or those associated with a super-spreading event (5 or more transmissions). Logistic regression analyses were used to evaluate the factors for MERS-CoV transmission.

Results.

Compared to nonspreaders, spreaders exhibited a longer interval from symptom onset to isolation (7 days vs 3 days) and more frequent pre-isolation pneumonia diagnoses (68.2% vs 17.1%). Spreaders also exhibited higher values for pre-isolation contacts (149 vs 17.5), pre-isolation hospitalization (68.2% vs 16.5%), and emergency room (ER) visits (50% vs 7.3%). Spreaders exhibited lower cycle thresholds for the upE and ORF1a genes (22.7 vs 27.2 and 23.7 vs 27.9, respectively). In multivariate analysis, transmission was independently associated with the cycle threshold (odds ratio [OR], 0.84; 95% confidence interval [CI], 0.75–0.96) and pre-isolation hospitalization or ER visits (OR, 6.82; 95% CI, 2.06–22.84). The super-spreading events exhibited higher values for pre-isolation contacts (777 vs 78), pre-isolation ER visits (100% vs 35.3%), and doctor shopping (100% vs 47.1%) compared to non-super-spreading events.

Conclusions.

These findings indicate that transmission is determined by host infectivity and the number of contacts, whereas super-spreading events were determined by the number of contacts and hospital visits. These relationships highlight the importance of rapidly enforcing infection control measures to prevent outbreaks.

Preventive behaviors by the level of perceived infection sensitivity during the Korea outbreak of Middle East Respiratory Syndrome in 2015

OBJECTIVES

This study was performed to investigate the relationship between community residents’ infection sensitivity and their levels of preventive behaviors during the 2015 Middle East Respiratory Syndrome (MERS) outbreak in Korea.

METHODS

Seven thousands two hundreds eighty one participants from nine areas in Gyeonggi-do including Pyeongtaek, the origin of the outbreak in 2015 agreed to participate in the survey and the data from 6,739 participants were included in the final analysis. The data on the perceived infection sensitivity were subjected to cluster analysis. The levels of stress, reliability/practice of preventive behaviors, hand washing practice and policy credibility during the outbreak period were analyzed for each cluster.

RESULTS

Cluster analysis of infection sensitivity due to the MERS outbreak resulted in classification of participants into four groups: the non-sensitive group (14.5%), social concern group (17.4%), neutral group (29.1%), and overall sensitive group (39.0%). A logistic regression analysis found that the overall sensitive group with high sensitivity had higher stress levels (17.80; 95% confidence interval [CI], 13.77 to 23.00), higher reliability on preventive behaviors (5.81; 95% CI, 4.84 to 6.98), higher practice of preventive behaviors (4.53; 95% CI, 3.83 to 5.37) and higher practice of hand washing (2.71; 95% CI, 2.13 to 3.43) during the outbreak period, compared to the non-sensitive group.

CONCLUSIONS

Infection sensitivity of community residents during the MERS outbreak correlated with gender, age, occupation, and health behaviors. When there is an outbreak in the community, there is need to maintain a certain level of sensitivity while reducing excessive stress, as well as promote the practice of preventive behaviors among local residents. In particular, target groups need to be notified and policies need to be established with a consideration of the socio-demographic characteristics of the community.

The critical care response to a hospital outbreak of Middle East respiratory syndrome coronavirus (MERS-CoV) infection: an observational study

Background

Middle East respiratory syndrome coronavirus (MERS-CoV) has caused several hospital outbreaks, including a major outbreak at King Abdulaziz Medical City, a 940-bed tertiary-care hospital in Riyadh, Saudi Arabia (August–September 2015). To learn from our experience, we described the critical care response to the outbreak.

Methods

This observational study was conducted at the Intensive Care Department which covered 5 ICUs with 60 single-bedded rooms. We described qualitatively and, as applicable, quantitatively the response of intensive care services to the outbreak. The clinical course and outcomes of healthcare workers (HCWs) who had MERS were noted.

Results

Sixty-three MERS patients were admitted to 3 MERS-designated ICUs during the outbreak (peak census = 27 patients on August 25, 2015, and the last new case on September 13, 2015). Most patients had multiorgan failure. Eight HCWs had MERS requiring ICU admission (median stay = 28 days): Seven developed acute respiratory distress syndrome, four were treated with prone positioning, four needed continuous renal replacement therapy and one had extracorporeal membrane oxygenation. The hospital mortality of ICU MERS patients was 63.4 % (0 % for the HCWs). In response to the outbreak, the number of negative-pressure rooms was increased from 14 to 38 rooms in 3 MERS-designated ICUs. Patients were managed with a nurse-to-patient ratio of 1:0.8. Infection prevention practices were intensified. As a surrogate, surface disinfectant and hand hygiene gel consumption increased by ~30 % and 17 N95 masks were used per patient/day on average. Family visits were restricted to 2 h/day. Although most ICU staff expressed concerns about acquiring MERS, all reported to work normally. During the outbreak, 27.0 % of nurses and 18.4 % of physicians working in the MERS-designated ICUs reported upper respiratory symptoms, and were tested for MERS-CoV. Only 2/196 (1.0 %) ICU nurses and 1/80 (1.3 %) physician tested positive, had mild disease and recovered fully. The total sick leave duration was 138 days for nurses and 30 days for physicians.

Conclusions

Our hospital outbreak of MERS resulted in 63 patients requiring organ support and prolonged ICU stay with a high mortality rate. The ICU response required careful facility and staff management and proper infection control and prevention practices.

A recombinant receptor-binding domain of MERS-CoV in trimeric form protects human dipeptidyl peptidase 4 (hDPP4) transgenic mice from MERS-CoV infection

Middle East respiratory syndrome (MERS) coronavirus (MERS-CoV) was first identified in 2012, and it continues to threaten human health worldwide. No MERS vaccines are licensed for human use, reinforcing the urgency to develop safe and efficacious vaccines to prevent MERS. MERS-CoV spike protein forms a trimer, and its receptor-binding domain (RBD) serves as a vaccine target. Nevertheless, the protective efficacy of RBD in its native trimeric form has never been evaluated. In this study, a trimeric protein, RBD-Fd, was generated by fusing RBD with foldon trimerization motif. It bound strongly to the receptor of MERS-CoV, dipeptidyl peptidase 4 (DPP4), and elicited robust RBD-specific neutralizing antibodies in mice, maintaining long-term neutralizing activity against MERS-CoV infection. RBD-Fd potently protected hDPP4 transgenic mice from lethal MERS-CoV challenge. These results suggest that MERS-CoV RBD in its trimeric form maintains native conformation and induces protective neutralizing antibodies, making it a candidate for further therapeutic development.

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A trimeric MERS-CoV protein (RBD-Fd) was constructed by fusing viral RBD with foldon trimerization motif.

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RBD-Fd bound strongly to dipeptidyl peptidase 4 (DPP4), the receptor of MERS-CoV, and RBD-specific neutralizing antibodies.

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RBD-Fd induced robust and long-term neutralizing antibodies, cross-neutralizing MERS pseudovirus of divergent strains.

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RBD-Fd potently protected hDPP4 transgenic mice from lethal MERS-CoV challenge.

Middle East respiratory syndrome coronavirus (MERS-CoV) outbreak in South Korea, 2015: epidemiology, characteristics and public health implications

Background

Since the first case of Middle East respiratory syndrome coronavirus (MERS-CoV) in South Korea was reported on 20^th May 2015, there have been 186 confirmed cases, 38 deaths and 16,752 suspected cases. Previously published research on South Korea's MERS outbreak was limited to the early stages, when few data were available. Now that the outbreak has ended, albeit unofficially, a more comprehensive review is appropriate.

Methods

Data were obtained through the MERS portal by the Ministry for Health and Welfare (MOHW) and Korea Centres for Disease Control and Prevention, press releases by MOHW, and reports by the MERS Policy Committee of the Korean Medical Association. Cases were analysed for general characteristics, exposure source, timeline and infection generation. Sex, age and underlying diseases were analysed for the 38 deaths.

Findings

Beginning with the index case that infected 28 others, an in-depth analysis was conducted. The average age was 55 years, which was a little higher than the global average of 50 years. As in most other countries, more men than women were affected. The case fatality rate was 19.9%, which was lower than the global rate of 38.7% and the rate in Saudi Arabia (36.5%). In total, 184 patients were infected nosocomially and there were no community-acquired infections. The main underlying diseases were respiratory diseases, cancer and hypertension. The main contributors to the outbreak were late diagnosis, quarantine failure of ‘super spreaders’, familial care-giving and visiting, non-disclosure by patients, poor communication by the South Korean Government, inadequate hospital infection management, and ‘doctor shopping’. The outbreak was entirely nosocomial, and was largely attributable to infection management and policy failures, rather than biomedical factors.