Ebola Virus-Specific Neutralizing Antibody Persists at High Levels in Survivors 2 Years After Resolution of Disease in a Sierra Leonean Cohort.

Ebola virus (EBOV) infection results in Ebola virus disease (EVD), an often severe disease with a nonspecific presentation. Since its recognition, periodic outbreaks of EVD continue to occur in sub-Saharan Africa. The 2013-2016 West African EVD outbreak was the largest recorded, resulting in a substantial cohort of EVD survivors with persistent health complaints and variable immune responses. In this study, we characterize humoral immune responses in EVD survivors and their contacts in Eastern Sierra Leone. We found high levels of EBOV IgG in EVD survivors and lower yet substantial antibody levels in household contacts, suggesting subclinical transmission. Neutralizing antibody function was prevalent but variable in EVD survivors, raising questions about the durability of immune responses from natural infection with EBOV. Additionally, we found that certain discrete symptoms-ophthalmologic and auditory-are associated with EBOV IgG seropositivity, while an array of symptoms are associated with the presence of neutralizing antibody.

COVID-19 hospitalization risk after outpatient nirmatrelvir/ritonavir use, January to August 2022, North Carolina.

BACKGROUND: In the USA, nirmatrelvir/ritonavir is authorized for the treatment of mild-to-moderate COVID-19 in patients at least 12 years of age, at high risk for progression to severe COVID-19. OBJECTIVES: To estimate the impact of outpatient nirmatrelvir/ritonavir on COVID-19 hospitalization risk in a US healthcare system. METHODS: We conducted a cohort study using electronic health records among outpatients with a positive SARS-CoV-2 PCR test between January and August 2022. We evaluated the association of nirmatrelvir/ritonavir therapy with time to hospitalization by estimating adjusted HRs and assessed the impact of nirmatrelvir/ritonavir on predicted COVID-19 hospitalizations using machine-learning methods. RESULTS: Among 44 671 patients, 4948 (11%) received nirmatrelvir/ritonavir, and 201 (0.4%) were hospitalized within 28 days of COVID-19 diagnosis. Nirmatrelvir/ritonavir recipients were more likely to be older, white, vaccinated, have comorbidities and reside in areas with higher average socioeconomic status. The 28 day cumulative incidence of hospitalization was 0.06% (95% CI: 0.02%-0.17%) among nirmatrelvir/ritonavir recipients and 0.52% (95% CI: 0.46%-0.60%) among non-recipients. For nirmatrelvir/ritonavir versus no therapy, the age-adjusted HR was 0.08 (95% CI: 0.03-0.26); the fully adjusted HR was 0.16 (95% CI: 0.05-0.50). In the machine-learning model, the primary features reducing predicted hospitalization risk were nirmatrelvir/ritonavir, younger age, vaccination, female gender and residence in a higher socioeconomic status area. CONCLUSIONS: COVID-19 hospitalization risk was reduced by 84% among nirmatrelvir/ritonavir recipients in a large, diverse healthcare system during the Omicron wave. These results suggest that nirmatrelvir/ritonavir remained highly effective in a setting substantially different than the original clinical trials.

Safety and Efficacy of Combination SARS-CoV-2 Neutralizing Monoclonal Antibodies Amubarvimab Plus Romlusevimab in Nonhospitalized Patients With COVID-19.

BACKGROUND: Development of safe and effective SARS-CoV-2 therapeutics is a high priority. Amubarvimab and romlusevimab are noncompeting anti-SARS-CoV-2 monoclonal antibodies with an extended half-life. OBJECTIVE: To assess the safety and efficacy of amubarvimab plus romlusevimab. DESIGN: Randomized, placebo-controlled, phase 2 and 3 platform trial. (ClinicalTrials.gov: NCT04518410). SETTING: Nonhospitalized patients with COVID-19 in the United States, Brazil, South Africa, Mexico, Argentina, and the Philippines. PATIENTS: Adults within 10 days onset of symptomatic SARS-CoV-2 infection who are at high risk for clinical progression. INTERVENTION: Combination of monoclonal antibodies amubarvimab plus romlusevimab or placebo. MEASUREMENTS: Nasopharyngeal and anterior nasal swabs for SARS-CoV-2, COVID-19 symptoms, safety, and progression to hospitalization or death. RESULTS: Eight-hundred and seven participants who initiated the study intervention were included in the phase 3 analysis. Median age was 49 years (quartiles, 39 to 58); 51% were female, 18% were Black, and 50% were Hispanic or Latino. Median time from symptom onset at study entry was 6 days (quartiles, 4 to 7). Hospitalizations and/or death occurred in 9 (2.3%) participants in the amubarvimab plus romlusevimab group compared with 44 (10.7%) in the placebo group, with an estimated 79% reduction in events (P < 0.001). This reduction was similar between participants with 5 or less and more than 5 days of symptoms at study entry. Grade 3 or higher treatment-emergent adverse events through day 28 were seen less frequently among participants randomly assigned to amubarvimab plus romlusevimab (7.3%) than placebo (16.1%) (P < 0.001), with no severe infusion reactions or drug-related serious adverse events. LIMITATION: The study population was mostly unvaccinated against COVID-19 and enrolled before the spread of Omicron variants and subvariants. CONCLUSION: Amubarvimab plus romlusevimab was safe and significantly reduced the risk for hospitalization and/or death among nonhospitalized adults with mild to moderate SARS-CoV-2 infection at high risk for progression to severe disease. PRIMARY FUNDING SOURCE: National Institute of Allergy and Infectious Diseases of the National Institutes of Health.

Association Between Anterior Nasal and Plasma SARS-CoV-2 RNA Levels and Hospitalization or Death in Nonhospitalized Adults With Mild-to-Moderate COVID-19.

BACKGROUND: There is little information regarding severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA as a predictor for clinical outcomes in outpatients with mild-to-moderate coronavirus disease 2019 (COVID-19). METHODS: Anterior nasal (AN) and plasma SARS-CoV-2 RNA data from 2115 nonhospitalized adults who received monoclonal antibodies (mAbs) or placebo in the ACTIV-2/A5401 trial were analyzed for associations with hospitalization or death. RESULTS: One hundred two participants were hospitalized or died through 28 days of follow-up. Higher day 0 (pretreatment) AN RNA was associated with increasing risk of hospitalization/death (risk ratio [RR], 1.24 per log10 copies/mL [95% confidence interval {CI}, 1.04-1.49]) among placebo recipients, ranging from 3% to 16% for <2 to ≥6 log10 copies/mL. Although only 1% had quantifiable levels, there was a similar trend across day 0 plasma RNA categories. Higher day 3 AN RNA was associated with subsequent hospitalization/death among placebo recipients (RR, 1.42 per log10 copies/mL [95% CI, 1.00-2.03]), but not mAb recipients (RR, 1.02 per log10 copies/mL [95% CI, 0.68-1.56]). The proportion of treatment effect (reduction in hospitalizations/deaths after day 3 for mAb vs placebo) explained by day 3 AN RNA was 8%. CONCLUSIONS: SARS-CoV-2 RNA levels are predictive of hospitalization/death in the natural history setting, but AN RNA levels may not be a reliable surrogate marker of mAb treatment effect in COVID-19 trials. Clinical Trials Registration. NCT04518410.

Post-Ebola Symptoms 7 Years After Infection: The Natural History of Long Ebola.

BACKGROUND: Lingering symptoms have been reported by survivors of Ebola virus disease (EVD). There are few data describing the persistence and severity of these symptoms over time. METHODS: Symptoms of headache, fatigue, joint pain, muscle pain, hearing loss, visual loss, numbness of hands or feet were longitudinally assessed among participants in the Liberian Ebola Survivors Cohort study. Generalized linear mixed effects models, adjusted for sex and age, were used to calculate the odds of reporting a symptom and it being rated as highly interfering with life. RESULTS: From June 2015 to June 2016, 326 survivors were enrolled a median of 389 days (range 51-614) from acute EVD. At baseline 75.2% reported at least 1 symptom; 85.8% were highly interfering with life. Over a median follow-up of 5.9 years, reporting of any symptom declined (odds ratio for each 90 days of follow-up = 0.96, 95% confidence interval [CI]: .95, .97; P < .0001) with all symptoms declining except for numbness of hands or feet. Rating of any symptom as highly interfering decreased over time. Among 311 with 5 years of follow-up, 52% (n = 161) reported a symptom and 29% (n = 47) of these as highly interfering with their lives. CONCLUSIONS: Major post-EVD symptoms are common early during convalescence and decline over time along with severity. However, even 5 years after acute infection, a majority continue to have symptoms and, for many, these continue to greatly impact their lives. These findings call for investigations to identify the mechanisms of post-EVD sequelae and therapeutic interventions to benefit the thousands of effected EVD survivors.

Infectious Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Virus in Symptomatic Coronavirus Disease 2019 (COVID-19) Outpatients: Host, Disease, and Viral Correlates.

BACKGROUND: Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infectious virus isolation in outpatients with coronavirus disease 2019 (COVID-19) has been associated with viral RNA levels and symptom duration, little is known about the host, disease, and viral determinants of infectious virus detection. METHODS: COVID-19 adult outpatients were enrolled within 7 days of symptom onset. Clinical symptoms were recorded via patient diary. Nasopharyngeal swabs were collected to quantitate SARS-CoV-2 RNA by reverse transcriptase polymerase chain reaction and for infectious virus isolation in Vero E6-cells. SARS-CoV-2 antibodies were measured in serum using a validated ELISA assay. RESULTS: Among 204 participants with mild-to-moderate symptomatic COVID-19, the median nasopharyngeal viral RNA was 6.5 (interquartile range [IQR] 4.7-7.6 log10 copies/mL), and 26% had detectable SARS-CoV-2 antibodies (immunoglobulin (Ig)A, IgM, IgG, and/or total Ig) at baseline. Infectious virus was recovered in 7% of participants with SARS-CoV-2 antibodies compared to 58% of participants without antibodies (prevalence ratio [PR] = 0.12, 95% confidence interval [CI]: .04, .36; P = .00016). Infectious virus isolation was also associated with higher levels of viral RNA (mean RNA difference +2.6 log10, 95% CI: 2.2, 3.0; P < .0001) and fewer days since symptom onset (PR = 0.79, 95% CI: .71, .88 per day; P < .0001). CONCLUSIONS: The presence of SARS-CoV-2 antibodies is strongly associated with clearance of infectious virus. Seropositivity and viral RNA levels are likely more reliable markers of infectious virus clearance than subjective measure of COVID-19 symptom duration. Virus-targeted treatment and prevention strategies should be administered as early as possible and ideally before seroconversion. CLINICAL TRIALS REGISTRATION: NCT04405570.

The prevalence of Post-Ebola Syndrome hearing loss, Sierra Leone.

BACKGROUND: Globally, hearing loss is the second leading cause of disability, affecting approximately 18.7% of the world's population. However, the burden of hearing loss is unequally distributed, with the majority of affected individuals located in Asia or Sub-Saharan Africa. Following the 2014 West African Ebola Outbreak, disease survivors began to describe hearing loss as part of the constellation of symptoms known as Post-Ebola Syndrome. The goal of this study was to more fully characterize hearing loss among Ebola Virus Disease (EVD) survivors. METHODOLOGY AND PRINCIPAL FINDINGS: EVD survivors and their household contacts were recruited (n = 1,12) from Eastern Sierra Leone. Each individual completed a symptom questionnaire, physical exam, and a two-step audiometry process measuring both air and bone conduction thresholds. In comparison to contacts, EVD survivors were more likely to have complaints or abnormal findings affecting every organ system. A significantly greater percentage of EVD survivors were found to have hearing loss in comparison to contacts (23% vs. 9%, p < 0.001). Additionally, survivors were more likely to have bilateral hearing loss of a mixed etiology. Logistic regression revealed that the presence of any symptoms of middle or inner ear (p < 0.001), eye (p = 0.005), psychiatric (p = 0.019), and nervous system (p = 0.037) increased the odds of developing hearing loss. CONCLUSIONS AND SIGNIFICANCE: This study is the first to use an objective and standardized measurement to report hearing loss among EVD survivors in a clinically meaningful manner. In this study it was found that greater than 1/5th of EVD survivors develop hearing loss. The association between hearing impairment and symptoms affecting the eye and nervous system may indicate a similar mechanism of pathogenesis, which should be investigated further. Due to the quality of life and socioeconomic detriments associated with untreated hearing loss, a greater emphasis must be placed on understanding and mitigating hearing loss following survival to aid in economic recovery following infectious disease epidemics.

Outpatient Treatment of Severe Acute Respiratory Syndrome Coronavirus 2 Infection to Prevent Coronavirus Disease 2019 Progression.

As of March 2021, coronavirus disease 2019 (COVID-19) had caused more than 123 million infections and almost 3 million deaths worldwide. Dramatic advances have been made in vaccine development and nonpharmaceutical interventions to stop the spread of infection. However, treatments to stop disease progression are limited. A wide variety of "repurposed" drugs evaluated for treatment of COVID-19 have had little or no benefit. More recently, intravenous monoclonal antibody (mAb) combinations have been authorized by the US Food and Drug Administration for emergency use for outpatients with mild to moderate COVID-19 including some active against emerging severe acute respiratory syndrome coronavirus 2 variants of concern. Easier to administer therapeutics including intramuscular and subcutaneous mAbs and oral antivirals are in clinical trials. Reliable, safe, effective COVID-19 treatment for early infection in the outpatient setting is of urgent and critical importance. Availability of such treatment should lead to reduced progression of COVID-19.

Long-term Complications of Ebola Virus Disease: Prevalence and Predictors of Major Symptoms and the Role of Inflammation.

BACKGROUND: Cohort studies have reported a high prevalence of musculoskeletal, neurologic, auditory, and visual complications among Ebola virus disease (EVD) survivors. However, little is known about the host- and disease-related predictors of these symptoms and their etiological mechanisms. METHODS: The presence and patterns of 8 cardinal symptoms that are most commonly reported following EVD survival were assessed in the 326 EVD survivors who participated in the ongoing longitudinal Liberian EVD Survivor Study. At quarterly study visits, symptoms that developed since acute EVD were recorded and blood was collected for biomarkers of inflammation and immune activation. RESULTS: At baseline (mean 408 days from acute EVD), 75.5% of survivors reported at least 1 new cardinal symptom since surviving EVD, which in 85.8% was rated as highly interfering with life. Two or more incident symptoms were reported by 61.0% of survivors, with pairings of joint pain, headache, or fatigue the most frequent. Women were significantly more likely than men to report headache, while older age was significantly associated with musculoskeletal and visual symptoms. In analyses adjusted for multiple comparisons, no statistically significant association was found between any symptom and 26 markers of inflammation and immune activation. Symptom frequency remained largely unchanged during study follow-up. CONCLUSIONS: Post-EVD complications occur in a majority of survivors and remain present more than 4 years after acute infection. An association between markers of inflammation and immune activation and individual symptoms was not found, suggesting an alternative etiology for persistent post-EVD symptomatology.

Evidence-based guidelines for supportive care of patients with Ebola virus disease.

The 2013-16 Ebola virus disease outbreak in west Africa was associated with unprecedented challenges in the provision of care to patients with Ebola virus disease, including absence of pre-existing isolation and treatment facilities, patients' reluctance to present for medical care, and limitations in the provision of supportive medical care. Case fatality rates in west Africa were initially greater than 70%, but decreased with improvements in supportive care. To inform optimal care in a future outbreak of Ebola virus disease, we employed the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) methodology to develop evidence-based guidelines for the delivery of supportive care to patients admitted to Ebola treatment units. Key recommendations include administration of oral and, as necessary, intravenous hydration; systematic monitoring of vital signs and volume status; availability of key biochemical testing; adequate staffing ratios; and availability of analgesics, including opioids, for pain relief.

ZMapp Reinforces the Airway Mucosal Barrier Against Ebola Virus.

Filoviruses, including Ebola, have the potential to be transmitted via virus-laden droplets deposited onto mucus membranes. Protecting against such emerging pathogens will require understanding how they may transmit at mucosal surfaces and developing strategies to reinforce the airway mucus barrier. Here, we prepared Ebola pseudovirus (with Zaire strain glycoproteins) and used high-resolution multiple-particle tracking to track the motions of hundreds of individual pseudoviruses in fresh and undiluted human airway mucus isolated from extubated endotracheal tubes. We found that Ebola pseudovirus readily penetrates human airway mucus. Addition of ZMapp, a cocktail of Ebola-binding immunoglobulin G antibodies, effectively reduced mobility of Ebola pseudovirus in the same mucus secretions. Topical delivery of ZMapp to the mouse airways also facilitated rapid elimination of Ebola pseudovirus. Our work demonstrates that antibodies can immobilize virions in airway mucus and reduce access to the airway epithelium, highlighting topical delivery of pathogen-specific antibodies to the lungs as a potential prophylactic or therapeutic approach against emerging viruses or biowarfare agents.

Anti-Ebola Virus Antibody Levels in Convalescent Plasma and Viral Load After Plasma Infusion in Patients With Ebola Virus Disease.

Background: Ebola virus (EBOV) neutralizing antibody in plasma may reduce viral load following administration of plasma to patients with Ebola virus disease (EVD), but measurement of these antibodies is complex. Methods: Anti-EBOV antibody was measured by 2 neutralization and 2 enzyme-linked immunosorbent assays (ELISAs) in convalescent plasma (ECP) from 100 EVD survivor donors in Liberia. Viral load was assessed repetitively in patients with EVD participating in a clinical trial of enhanced standard of care plus ECP. Results: All 4 anti-EBOV assays were highly concordant for detection of EBOV antibody. Antibodies were not detected in plasma specimens obtained from 15 of 100 donors, including 7 with documented EBOV-positive reverse-transcription polymerase chain reaction during EVD. Viral load was reduced following each dose in the 2 clinical trial participants who received ECP with higher antibody levels but not in the 2 who received ECP with lower antibody levels. Conclusions: Recovery from EVD can occur with absence of detectable anti-EBOV antibody several months after disease onset. ELISAs may be useful to select ECP donors or identify ECP units that contain neutralizing antibody. ECP with higher anti-EBOV antibody levels may have greater effect on EBOV load-an observation that requires further investigation. Clinical Trials Registration: NCT02333578.

Clinical presentation of patients with Ebola virus disease in Conakry, Guinea.

BACKGROUND: In March 2014, the World Health Organization was notified of an outbreak of Zaire ebolavirus in a remote area of Guinea. The outbreak then spread to the capital, Conakry, and to neighboring countries and has subsequently become the largest epidemic of Ebola virus disease (EVD) to date. METHODS: From March 25 to April 26, 2014, we performed a study of all patients with laboratory-confirmed EVD in Conakry. Mortality was the primary outcome. Secondary outcomes included patient characteristics, complications, treatments, and comparisons between survivors and nonsurvivors. RESULTS: Of 80 patients who presented with symptoms, 37 had laboratory-confirmed EVD. Among confirmed cases, the median age was 38 years (interquartile range, 28 to 46), 24 patients (65%) were men, and 14 (38%) were health care workers; among the health care workers, nosocomial transmission was implicated in 12 patients (32%). Patients with confirmed EVD presented to the hospital a median of 5 days (interquartile range, 3 to 7) after the onset of symptoms, most commonly with fever (in 84% of the patients; mean temperature, 38.6°C), fatigue (in 65%), diarrhea (in 62%), and tachycardia (mean heart rate, >93 beats per minute). Of these patients, 28 (76%) were treated with intravenous fluids and 37 (100%) with antibiotics. Sixteen patients (43%) died, with a median time from symptom onset to death of 8 days (interquartile range, 7 to 11). Patients who were 40 years of age or older, as compared with those under the age of 40 years, had a relative risk of death of 3.49 (95% confidence interval, 1.42 to 8.59; P=0.007). CONCLUSIONS: Patients with EVD presented with evidence of dehydration associated with vomiting and severe diarrhea. Despite attempts at volume repletion, antimicrobial therapy, and limited laboratory services, the rate of death was 43%.

Validation of the Cepheid GeneXpert for Detecting Ebola Virus in Semen.

BACKGROUND: Ebola virus (EBOV) RNA persistence in semen, reported sexual transmission, and sporadic clusters at the end of the 2013-2016 epidemic have prompted recommendations that male survivors refrain from unprotected sex unless their semen is confirmed to be EBOV free. However, there is no fully validated assay for EBOV detection in fluids other than blood. METHODS: The Cepheid Xpert Ebola assay for EBOV RNA detection was validated for whole semen and blood using samples obtained from uninfected donors and spiked with inactivated EBOV. The validation procedure incorporated standards from Clinical and Laboratory Standards Institute and Good Clinical Laboratory Practices guidelines for evaluating molecular devices for use in infectious disease testing. RESULTS: The assay produced limits of detection of 1000 copies/mL in semen and 275 copies/mL in blood. Limits of detection for both semen and blood increased with longer intervals between collection and testing, with acceptable results obtained up to 72 hours after specimen collection. CONCLUSIONS: The Cepheid Xpert Ebola assay is accurate and precise for detecting EBOV in whole semen. A validated assay for EBOV RNA detection in semen informs the care of male survivors of Ebola, as well as recommendations for public health.

CDC Safety Training Course for Ebola Virus Disease Healthcare Workers.

Response to sudden epidemic infectious disease emergencies can demand intensive and specialized training, as demonstrated in 2014 when Ebola virus disease (EVD) rapidly spread throughout West Africa. The medical community quickly became overwhelmed because of limited staff, supplies, and Ebola treatment units (ETUs). Because a mechanism to rapidly increase trained healthcare workers was needed, the US Centers for Disease Control and Prevention developed and implemented an introductory EVD safety training course to prepare US healthcare workers to work in West Africa ETUs. The goal was to teach principles and practices of safely providing patient care and was delivered through lectures, small-group breakout sessions, and practical exercises. During September 2014-March 2015, a total of 570 participants were trained during 16 course sessions. This course quickly increased the number of clinicians who could provide care in West Africa ETUs, showing the feasibility of rapidly developing and implementing training in response to a public health emergency.

Apheresis for collection of Ebola convalescent plasma in Liberia.

PURPOSE: This report describes initiation of apheresis capability in Liberia, Africa to support a clinical trial of convalescent plasma therapy for Ebola Virus Disease. METHODS: A bloodmobile was outfitted in the United States as a four-bed apheresis unit with capabilities including pathogen reduction, electronic blood establishment computer system, designated areas for donor counseling and laboratory testing, and onboard electrical power generation. After air transport to Liberia, the bloodmobile was positioned at ELWA Hospital, Monrovia, and connected to the hospital's power grid. Liberian staff were trained to conduct donor screening, which included questionnaire and onsite blood typing and transfusion transmitted infection (TTI) testing, and plasma collection and processing. RESULTS: The bloodmobile was operational within 3 weeks after arrival of the advance team. Of 101 donors who passed the pre-screening questionnaire, 32 were deferred. Twenty-eight of ninty-nine tested survivors were deferred for positive transfusion transmitted infection (TTI) tests; twenty-one were positive for hepatitis B, hepatitis C, or human immunodeficiency virus. The majority of donors had type O blood; all but one were Rh positive. Forty-three survivors donated at least once; eighty-nine apheresis attempts resulted in eighty-one successful collections. CONCLUSIONS: Apheresis capability was emergently established in Liberia to support an efficacy trial of Ebola Convalescent Plasma. Extensive cooperation among multinational team members, engineers, logisticians, and blood safety technical personnel at the operational site was required to surmount challenges to execution posed by logistical factors. The high proportion of positive TTI tests supported the use of a pathogen reduction system to enhance product safety. J. Clin. Apheresis 32:175-181, 2017. © 2016 Wiley Periodicals, Inc.

Ebola Virus Shedding and Transmission: Review of Current Evidence.

BACKGROUND: The magnitude of the 2013-2016 Ebola virus disease outbreak in West Africa was unprecedented, with >28 500 reported cases and >11 000 deaths. Understanding the key elements of Ebola virus transmission is necessary to implement adequate infection prevention and control measures to protect healthcare workers and halt transmission in the community. METHODS: We performed an extensive PubMed literature review encompassing the period from discovery of Ebola virus, in 1976, until 1 June 2016 to evaluate the evidence on modes of Ebola virus shedding and transmission. FINDINGS: Ebola virus has been isolated by cell culture from blood, saliva, urine, aqueous humor, semen, and breast milk from infected or convalescent patients. Ebola virus RNA has been noted in the following body fluids days or months after onset of illness: saliva (22 days), conjunctiva/tears (28 days), stool (29 days), vaginal fluid (33 days), sweat (44 days), urine (64 days), amniotic fluid (38 days), aqueous humor (101 days), cerebrospinal fluid (9 months), breast milk (16 months [preliminary data]), and semen (18 months). Nevertheless, the only documented cases of secondary transmission from recovered patients have been through sexual transmission. We did not find strong evidence supporting respiratory or fomite-associated transmission.

Confronting Ebola as a Sexually Transmitted Infection.

The unprecedented Ebola outbreak that devastated West Africa evolved within months from a regional outbreak to a global public health emergency. While the rate of confirmed cases declined dramatically, sporadic clusters of Ebola virus disease (EVD) continue well beyond the double incubation period of 42 days used to declare a nation Ebola-free. At the same time, evidence that the virus persists in genital fluids and can be sexually transmitted, along with the potential for lingering virus in other body compartments to permit recrudescence of EVD, has shaken our thinking of what it takes to achieve lasting control of an Ebola epidemic. A comprehensive response to the threat of persistence and sexual transmission of Ebola is required and should build on accessible longitudinal medical care of survivors and accurate genital fluid testing for Ebola. Control of this and future Ebola outbreaks will depend on our ability to recognize and respond to this persistence of the virus in those who survive.

Ebola virus disease and critical illness.

As of 20 May 2016 there have been 28,646 cases and 11,323 deaths resulting from the West African Ebola virus disease (EVD) outbreak reported to the World Health Organization. There continue to be sporadic flare-ups of EVD cases in West Africa.EVD presentation is nonspecific and characterized initially by onset of fatigue, myalgias, arthralgias, headache, and fever; this is followed several days later by anorexia, nausea, vomiting, diarrhea, and abdominal pain. Anorexia and gastrointestinal losses lead to dehydration, electrolyte abnormalities, and metabolic acidosis, and, in some patients, acute kidney injury. Hypoxia and ventilation failure occurs most often with severe illness and may be exacerbated by substantial fluid requirements for intravascular volume repletion and some degree of systemic capillary leak. Although minor bleeding manifestations are common, hypovolemic and septic shock complicated by multisystem organ dysfunction appear the most frequent causes of death.Males and females have been equally affected, with children (0-14 years of age) accounting for 19 %, young adults (15-44 years) 58 %, and older adults (≥45 years) 23 % of reported cases. While the current case fatality proportion in West Africa is approximately 40 %, it has varied substantially over time (highest near the outbreak onset) according to available resources (40-90 % mortality in West Africa compared to under 20 % in Western Europe and the USA), by age (near universal among neonates and high among older adults), and by Ebola viral load at admission.While there is no Ebola virus-specific therapy proven to be effective in clinical trials, mortality has been dramatically lower among EVD patients managed with supportive intensive care in highly resourced settings, allowing for the avoidance of hypovolemia, correction of electrolyte and metabolic abnormalities, and the provision of oxygen, ventilation, vasopressors, and dialysis when indicated. This experience emphasizes that, in addition to evaluating specific medical treatments, improving the global capacity to provide supportive critical care to patients with EVD may be the greatest opportunity to improve patient outcomes.