Diagnostic delays in Middle East respiratory syndrome coronavirus patients and health systems

Estimating the Epidemic Size of Superspreading Coronavirus Outbreaks in Real Time: Quantitative Study

BACKGROUND

Novel coronaviruses have emerged and caused major epidemics and pandemics in the past 2 decades, including SARS-CoV-1, MERS-CoV, and SARS-CoV-2, which led to the current COVID-19 pandemic. These coronaviruses are marked by their potential to produce disproportionally large transmission clusters from superspreading events (SSEs). As prompt action is crucial to contain and mitigate SSEs, real-time epidemic size estimation could characterize the transmission heterogeneity and inform timely implementation of control measures.

OBJECTIVE

This study aimed to estimate the epidemic size of SSEs to inform effective surveillance and rapid mitigation responses.

METHODS

We developed a statistical framework based on back-calculation to estimate the epidemic size of ongoing coronavirus SSEs. We first validated the framework in simulated scenarios with the epidemiological characteristics of SARS, MERS, and COVID-19 SSEs. As case studies, we retrospectively applied the framework to the Amoy Gardens SARS outbreak in Hong Kong in 2003, a series of nosocomial MERS outbreaks in South Korea in 2015, and 2 COVID-19 outbreaks originating from restaurants in Hong Kong in 2020.

RESULTS

The accuracy and precision of the estimation of epidemic size of SSEs improved with longer observation time; larger SSE size; and more accurate prior information about the epidemiological characteristics, such as the distribution of the incubation period and the distribution of the onset-to-confirmation delay. By retrospectively applying the framework, we found that the 95% credible interval of the estimates contained the true epidemic size after 37% of cases were reported in the Amoy Garden SARS SSE in Hong Kong, 41% to 62% of cases were observed in the 3 nosocomial MERS SSEs in South Korea, and 76% to 86% of cases were confirmed in the 2 COVID-19 SSEs in Hong Kong.

CONCLUSIONS

Our framework can be readily integrated into coronavirus surveillance systems to enhance situation awareness of ongoing SSEs.

Factors Associated With Diagnostic Delays in Human Brucellosis in Tongliao City, Inner Mongolia Autonomous Region, China

The diagnostic delays pose a huge challenge to human brucellosis (HB), which increases the risk of chronicity and complications with a heavy disease burden. This study aimed to quantify and identify the associated factors in the diagnostic delays to its prevention, reduction, and elimination. This study analyzed risk factors associated with the diagnostic delays in a cross-sectional study with data collected from Tongliao City, Inner Mongolia Autonomous Region of China. Diagnostic delays were defined with a cutoff of 30, 60, and 90 days. In different delay groups, risk factors of diagnostic delays were analyzed by univariate analysis and modeled by multivariate logistic regression analysis. A total of 14,506 cases were collected between January 1, 2005, and December 31, 2017, of which the median diagnostic delays was 29 days [interquartile range (IQR): 14–54 days]. Logistic regression analysis indicated that the older age category was associated with longer diagnostic delays across all groups. Longer diagnostic delays increase with age among three delay groups (p for trend <0.001). Occupation as herdsman was associated with shorter diagnostic delays in group 1 with 30 days [adjusted odds ratio (aOR), 0.890 (95% CI 0.804–0.986)]. Diagnostic delays was shorter in patients with brucellosis who were reported in CDC in all delay groups [aOR 0.738 (95% CI 0.690–0.790), 0.539 (95% CI 0.497–0.586), and 0.559 (95% CI 0.504–0.621)]. Pastoral/agricultural area was associated with shorter diagnostic delays in group 1 with 30 days [aOR, 0.889 (95%CI 0.831–0.951)] and group 3 with 90 days [aOR, 0.806 (95%CI 0.727–0.893)]. Stratified analysis showed that the older age category was associated with an increased risk of a long delay in both genders (p < 0.05). The older age group-to-youth group OR increased along with increased delay time (p for trend <0.001). Furthermore, the pastoral/agricultural area was associated with a shorter delay in males (p < 0.05). Delays exist in the diagnosis of HB. We should pay great attention to the risk factors of diagnostic delays, such as older population, non-herdsman, non-pastoral/agricultural area, non-disease prevention, and control agencies. Effective measures should shorten the diagnostic delays, achieve early detection, diagnosis, and treatment, and reduce the risk of HB's chronicity, complications, and economic burden.

Developing therapeutic approaches for twenty-first-century emerging infectious viral diseases

The twenty-first century has already recorded more than ten major epidemic or pandemic virus emergence events, including the ongoing and devastating coronavirus disease 2019 (COVID-19) pandemic. As viral disease emergence is expected to accelerate, these data dictate a need for proactive approaches to develop broadly active family-specific and cross-family therapeutics for use in future disease outbreaks. Emphasis should focus not only on the development of broad-spectrum small-molecule and antibody direct-acting antivirals, but also on host-factor therapeutics, including repurposing previously approved or in-pipeline drugs. Another new class of therapeutics with great antiviral therapeutic potential is RNA-based therapeutics. Rather than only focusing on known risks, dedicated efforts must be made toward pre-emptive research focused on outbreak-prone virus families, ultimately offering a strategy to shorten the gap between outbreak and response. Emphasis should also focus on orally available drugs for outpatient use, if possible, and on identifying combination therapies that combat viral and immune-mediated pathologies, extend the effectiveness of therapeutic windows and reduce drug resistance. While such an undertaking will require new vision, dedicated funding and private, federal and academic partnerships, this approach offers hope that global populations need never experience future pandemics such as COVID-19.

Product of natural evolution (SARS, MERS, and SARS-CoV-2); deadly diseases, from SARS to SARS-CoV-2

SARS-CoV-2, the virus causing COVID-19, is a single-stranded RNA virus belonging to the order Nidovirales, family Coronaviridae, and subfamily Coronavirinae. SARS-CoV-2 entry to cellsis initiated by the binding of the viral spike protein (S) to its cellular receptor. The roles of S protein in receptor binding and membrane fusion makes it a prominent target for vaccine development. SARS-CoV-2 genome sequence analysis has shown that this virus belongs to the beta-coronavirus genus, which includes Bat SARS-like coronavirus, SARS-CoV and MERS-CoV. A vaccine should induce a balanced immune response to elicit protective immunity. In this review, we compare and contrast these three important CoV diseases and how they inform on vaccine development.

The Current and Future State of Vaccines, Antivirals and Gene Therapies Against Emerging Coronaviruses

Emerging coronaviruses (CoV) are constant global public health threats to society. Multiple ongoing clinical trials for vaccines and antivirals against CoVs showcase the availability of medical interventions to both prevent and treat the future emergence of highly pathogenic CoVs in human. However, given the diverse nature of CoVs and our close interactions with wild, domestic and companion animals, the next epidemic zoonotic CoV could resist the existing vaccines and antivirals developed, which are primarily focused on Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) and Middle East Respiratory Syndrome Coronavirus (MERS CoV). In late 2019, the novel CoV (SARS-CoV-2) emerged in Wuhan, China, causing global public health concern. In this review, we will summarize the key advancements of current vaccines and antivirals against SARS-CoV and MERS-CoV as well as discuss the challenge and opportunity in the current SARS-CoV-2 crisis. At the end, we advocate the development of a "plug-and-play" platform technologies that could allow quick manufacturing and administration of broad-spectrum countermeasures in an outbreak setting. We will discuss the potential of AAV-based gene therapy technology for in vivo therapeutic antibody delivery to combat SARS-CoV-2 outbreak and the future emergence of severe CoVs.

The first clusters of Middle East respiratory syndrome coronavirus in Oman: Time to act

INTRODUCTION

Middle East respiratory syndrome coronavirus (MERS-CoV), is an emerging infectious disease of growing global importance. This review describes the latest MERS-CoV clusters and the first cases of nosocomial transmission within health care facilities in Oman. We have highlighted lessons learned and proposed steps to prevent healthcare-associated infections.

METHODS

A descriptive analysis of MERS-CoV cases was conducted between January 23 and February 16, 2019. The data from officials and other published sources used.

RESULTS

Thirteen laboratory-confirmed cases of MERS-CoV were reported from three simultaneous clusters from two governorates without an epidemiological link between the clusters. Two clusters were reported from North Al Batinah Governorate, with nine cases (69%) and 1 cluster from South Ash Sharqiyah Governorate with four cases (31%). In total, four deaths were reported (case fatality rate 31%). Four cases (31%) reported were household contacts from the first cluster, 3 (23%) were nosocomial transmission in health care facilities (two for first and one from the second cluster) and 7 (54%) were community-acquired cases.

CONCLUSIONS

The first local clusters of MERS-CoV reported with evidence suggestive of healthcare and household-associated transmission. Early diagnosis and strict implementation of infection control measures remain fundamental in preventing and managing MERS-CoV infection.

Climate factors and incidence of Middle East respiratory syndrome coronavirus

Background

Our understanding of climate factors and their links to the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) outbreaks is incomplete. This study aimed to estimate the monthly incidence of MERS-CoV cases and to investigate their correlation to climate factors.

Methods

The study used aggregated monthly MERS-CoV cases that reported to the Saudi Center for Disease Prevention and Control from the Riyadh Region between November 1, 2012 and December 31, 2018. Data on the meteorological situation throughout the study period was calculated based on Google reports on the Riyadh Region (24.7136 °N, 46.6753 °E). The Poisson regression was used to estimate the incidence rate ratio (IRR) and its 95% confidence intervals (CI) for each climate factor.

Results

A total of 712 MERS-CoV cases were included in the analysis (mean age 54.2 ± 9.9 years), and more than half (404) (56.1%) MERS-CoV cases were diagnosed during a five-month period from April to August. The highest peak timing positioned in August 2015, followed by April 2014, June 2017, March 2015, and June 2016. High temperatures (IRR = 1.054, 95% CI: 1.043–1.065) and a high ultraviolet index (IRR = 1.401, 95% CI: 1.331–1.475) were correlated with a higher incidence of MERS-CoV cases. However, low relative humidity (IRR = 0.956, 95% CI: 0.948–0.964) and low wind speed (IRR = 0.945, 95% CI: 0.912–0.979) were correlated with a lower incidence of MERS-CoV cases.

Conclusion

The novel coronavirus, MERS-CoV, is influenced by climate conditions with increasing incidence between April and August. High temperature, high ultraviolet index, low wind speed, and low relative humidity are contributors to increased MERS-CoV cases. The climate factors must be evaluated in hospitals and community settings and integrated into guidelines to serve as source of control measures to prevent and eliminate the risk of infection.