Ebola Virus Disease Outbreaks: Lessons Learned From Past and Facing Future Challenges.

INTRODUCTION: The purpose of this review is to examine African Ebola outbreaks from their first discovery to the present, to determine how the medical and public health response has changed and identify the causes for those changes. We sought to describe what is now known about the epidemiology and spread of Ebola virus disease (EVD) from the significant outbreaks that have occurred and outbreak control methods applied under often challenging circumstances. Given the substantial role that the U.S. Government and the U.S. DoD have played in the 2014 to 2016 West African Ebola outbreak, the role of the DoD and the U.S. African Command in controlling EVD is described. MATERIALS AND METHODS: A descriptive method design was used to collect and analyze all available Ebola outbreak literature using the PubMed database. An initial literature search was conducted by searching for, obtaining, and reading original source articles on all major global Ebola outbreaks. To conduct a focused search, we used initial search terms "Ebola outbreak," "Ebola virus disease," "Ebola response," "Ebola countermeasures," and also included each country's name where Ebola cases are known to have occurred. From the 4,673 unique articles obtained from this search and subsequent article title review, 307 articles were identified for potential inclusion. Following abstract and article review, 45 original source articles were used to compile the history of significant Ebola outbreaks. From this compilation, articles focused on each respective subsection of this review to delineate and describe the history of EVD and response, identifying fundamental changes, were obtained and incorporated. RESULTS: We present known Ebola virus and disease attributes, including a general description, seasonality and location, transmission capacity, clinical symptoms, surveillance, virology, historical EVD outbreaks and response, international support for Ebola outbreak response, U.S. DoD support, medical countermeasures supporting outbreak response, remaining gaps to include policy limitations, regional instability, climate change, migration, and urbanization, public health education and infrastructure, and virus persistence and public awareness. CONCLUSIONS: The health and societal impacts of EVD on Africa has been far-reaching, with about 35,000 cases and over 15,000 deaths, with small numbers of cases spreading globally. However, the history of combatting EVD reveals that there is considerable hope for African nations to quickly and successfully respond to Ebola outbreaks, through use of endemic resources including Africa CDC and African Partner Outbreak Response Alliance and the U.S. African Command with greater DoD reachback. Although there remains much to be learned about the Ebola virus and EVD including whether the potential for novel strains to become deadly emerging infections, invaluable vaccines, antivirals, and public health measures are now part of the resources that can be used to combat this disease.

Impact of SARS-CoV-2 Arrival Surveillance Screening by Nucleic Acid Amplification Versus Rapid Antigen Detection on Subsequent COVID-19 Infections in Military Trainees.

BACKGROUND: For persons entering congregate settings, optimal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) arrival surveillance screening method, nucleic acid amplification test (NAAT) versus rapid antigen detection test (RADT), is debated. To aid this, we sought to determine the risk of secondary symptomatic coronavirus disease 19 (COVID-19) among military trainees with negative arrival NAAT or RADT screening. METHODS: Individuals who arrived for US Air Force basic military training from 1 January-31 August 2021 were placed into training groups and screened for SARS-CoV-2 via NAAT or RADT. Secondary symptomatic COVID-19 cases within 2 weeks of training were then measured. A case cluster was defined as ≥5 individual symptomatic COVID-19 cases. RESULTS: 406 (1.6%) of 24 601 trainees screened positive upon arrival. The rate of positive screen was greater for those tested with NAAT versus RADT (2.5% vs 0.4%; RR: 5.4; 95% CI: 4.0-7.3; P < .001). The proportion of training groups with ≥1 positive individual screen was greater in groups screened via NAAT (57.5% vs 10.8%; RR: 5.31; 95% CI: 3.65-7.72; P < .001). However, NAAT versus RADT screening was not associated with a difference in number of training groups to develop a secondary symptomatic case (20.3% vs 22.5%; RR: .9; 95% CI: .66-1.23; P = .53) or case cluster of COVID-19 (4% vs 6.6%; RR: .61; 95% CI: .3-1.22; P = .16). CONCLUSIONS: NAAT versus RADT arrival surveillance screening method impacted individual transmission of COVID-19 but had no effect on number of training groups developing a secondary symptomatic case or case cluster. This study provides consideration for RADT arrival screening in congregate settings.

Sensitivity of Symptom-Based Screening for COVID-19 in Active Duty Basic Trainees.

INTRODUCTION: Symptomatic Coronavirus Disease 2019 (COVID-19) screening has been a cornerstone of case identification during the pandemic. Despite the myriad of COVID-19 symptoms, symptom screens have primarily focused on symptoms of influenza-like illnesses such as fever, cough, and dyspnea. It is unknown how well these symptoms identify cases in a young, healthy military population. This study aims to evaluate the utility of symptom-based screening in identifying COVID-19 through three different COVID-19 waves. MATERIALS AND METHODS: A convenience sample of 600 military trainees who arrived at Joint Base San Antonio-Lackland in 2021 and 2022 were included. Two hundred trainees with symptomatic COVID-19 before the emergence of the Delta variant (February-April 2021), when Delta variant was predominant (June-August 2021), and when Omicron was the predominant variant (January 2022) had their presenting symptoms compared. At each time point, the sensitivity of a screen for influenza-like illness symptoms was calculated. RESULTS: Of the 600 symptomatic active duty service members who tested positive for COVID-19, the most common symptoms were sore throat (n = 385, 64%), headache (n = 334, 56%), and cough (n = 314, 52%). Although sore throat was the most prominent symptom during Delta (n = 140, 70%) and Omicron (n = 153, 77%), headache was the most common before Delta (n = 93, 47%). There were significant differences in symptoms by vaccination status; for example, ageusia was more common in patients who were not completely vaccinated (3% vs. 0%, P = .01). Overall, screening for fever, cough, or dyspnea had a 65% sensitivity with its lowest sensitivity in the pre-Delta cases (54%) and highest sensitivity in Omicron cases (78%). CONCLUSIONS: In this descriptive cross-sectional study evaluating symptomatic military members with COVID-19, symptom prevalence varied based on predominant circulating COVID-19 variant as well as patients' vaccination status. As screening strategies evolve with the pandemic, changing symptom prevalence should be considered.

Response to a Serogroup B Meningococcal Disease Case Among Military Trainees.

We describe the public health response to a military trainee who developed serogroup B meningococcal disease while sharing underwater breathing equipment. Despite high transmission risk, with rapid isolation and postexposure prophylaxis administration, there were no secondary cases. This case supports carefully weighing serogroup B meningococcal vaccination in high-risk settings.

Sequencing SARS-CoV-2 from antigen tests.

Genomic surveillance empowers agile responses to SARS-CoV-2 by enabling scientists and public health analysts to issue recommendations aimed at slowing transmission, prioritizing contact tracing, and building a robust genomic sequencing surveillance strategy. Since the start of the pandemic, real time RT-PCR diagnostic testing from upper respiratory specimens, such as nasopharyngeal (NP) swabs, has been the standard. Moreover, respiratory samples in viral transport media are the ideal specimen for SARS-CoV-2 whole-genome sequencing (WGS). In early 2021, many clinicians transitioned to antigen-based SARS-CoV-2 detection tests, which use anterior nasal swabs for SARS-CoV-2 antigen detection. Despite this shift in testing methods, the need for whole-genome sequence surveillance remains. Thus, we developed a workflow for whole-genome sequencing with antigen test-derived swabs as an input rather than nasopharyngeal swabs. In this study, we use excess clinical specimens processed using the BinaxNOW™ COVID-19 Ag Card. We demonstrate that whole-genome sequencing from antigen tests is feasible and yields similar results from RT-PCR-based assays utilizing a swab in viral transport media.

Deaths Among U.S. Air Force Basic Military Trainees, 2008-2020.

INTRODUCTION: The U.S. Air Force (USAF) Basic Military Training (BMT), a rigorous training program for all enlisted members of the USAF, trains roughly 36,000 recruits annually. Transforming civilians into ready warrior airmen has inherent risks to trainee health, which has infrequently included death. While the average death rate at USAF BMT has decreased between 1956 and 2007 due to process improvement and preventive medicine efforts, further review is warranted to examine the deaths that have occurred since the last published period (1997-2007) and to determine the impact policy changes and updates have had on death rates since that time. Therefore, the purpose of this paper is to identify death rates and types from 2008 to 2020, explore policy implementation, and identify areas needing further improvement or modifications to the overall safety, fitness, and health of USAF BMT trainees. MATERIALS AND METHODS: All deaths were examined and reviewed from 2008 through 2020 for trainees attending the USAF BMT using medical records and autopsy reports. Death rates were calculated using the total population of trainees in a given year as well as over the entire 13-year study period. RESULTS: From 2008 to 2020, five deaths occurred among USAF BMT trainees (one cardiac, two exertional sickling due to sickle cell trait, one infection, and one suicide). This resulted in an overall average death rate of 1.08 per 100,000 trainees, as compared to 1.46 per 100,000 from 1997 to 2007. The last death in the study period occurred in 2016. CONCLUSION: A modest downward trend of average death rate has continued since 2007, and no deaths from 2016 through 2020 represents the longest time frame without any deaths at USAF BMT over all times reported (dating back to 1956) which suggest that emergency best practice policies are/have improved. However, cardiac death rate and suicide rate have not changed since the last report. Policies and practices should be continuously reviewed and refined to reduce the risk of death at USAF BMT.

Effect of Arrival Quarantine on Subsequent COVID-19 Testing in a Cohort of Military Basic Trainees.

INTRODUCTION: Basic Military Training at Joint Base San Antonio-Lackland implemented several sequential non-pharmaceutical interventions in response to coronavirus disease-2019 (COVID-19). One measure, arrival quarantine, has not been studied as a modern military disease prevention strategy. This study aimed to determine the effect of a 14-day arrival quarantine on symptomatic COVID-19 testing. MATERIAL AND METHODS: A retrospective cohort study compared symptomatic COVID-19 testing among all trainees who entered Basic Military Training between March 17, 2020, and April 17, 2020, before the implementation of universal arrival COVID-19 testing, during their first 2 weeks in arrival quarantine compared to the rest of their training. Furthermore, symptomatic COVID-19 testing in the last 5 weeks of training in those who completed arrival quarantine was compared to testing in the last 5 weeks for trainees who arrived between February 16, 2020, and March 16, 2020, and did not undergo arrival quarantine. Nominal variables were compared by chi-square test, and continuous variables were compared by Mann-Whitney U test. This study was approved as a public health surveillance project by the 59th Medical Wing Institutional Review Board. RESULTS: Five thousand five hundred and seventy-six trainees started training between February 16, 2020, and April 17, 2020, with 2,573 trainees undergoing an arrival quarantine compared to 3,003 trainees who did not. Trainees who underwent arrival quarantine had higher rates of COVID-19 testing while in arrival quarantine (10.5 tests per 1,000 trainee-weeks vs. 2.3, P ≤ .001) and higher rates of concomitant influenza testing (74% vs. 38%, P = .001) compared to after they completed quarantine. Trainees that completed quarantine had less symptomatic COVID-19 testing after day 14 of training (2.3 tests per 1,000 trainee-weeks vs. 14.3, P ≤ .001) and influenza testing (38% vs. 74%, P = .001) compared to trainees that did not undergo arrival quarantine. CONCLUSION: Arrival quarantine appears to be an effective non-pharmaceutical intervention associated with fewer symptomatic COVID-19 tests, especially after completion of quarantine.

Risk Factors Associated With COVID-19 Transmission Among US Air Force Trainees in a Congregant Setting.

Importance: Owing to concerns of coronavirus disease 2019 (COVID-19) outbreaks, many congregant settings are forced to close when cases are detected because there are few data on the risk of different markers of transmission within groups. Objective: To determine whether symptoms and laboratory results on the first day of COVID-19 diagnosis are associated with development of a case cluster in a congregant setting. Design, Setting, and Participants: This cohort study of trainees with COVID-19 from May 11 through August 24, 2020, was conducted at Joint Base San Antonio-Lackland, the primary site of entry for enlistment in the US Air Force. Symptoms and duration, known contacts, and cycle threshold for trainees diagnosed by reverse transcription-polymerase chain reaction were collected. A cycle threshold value represents the number of nucleic acid amplification cycles that occur before a specimen containing the target material generates a signal greater than the predetermined threshold that defines positivity. Cohorts with 5 or more individuals with COVID-19 infection were defined as clusters. Participants included 10 613 trainees divided into 263 parallel cohorts of 30 to 50 people arriving weekly for 7 weeks of training. Exposures: All trainees were quarantined for 14 days on arrival. Testing was performed on arrival, on day 14, and anytime during training when indicated. Protective measures included universal masking, physical distancing, and rapid isolation of trainees with COVID-19. Main Outcomes and Measures: Association between days of symptoms, specific symptoms, number of symptoms, or cycle threshold values of individuals diagnosed with COVID-19 via reverse transcription-polymerase chain reaction and subsequent transmission within cohorts. Results: In this cohort study of 10 613 US Air Force basic trainees in 263 cohorts, 403 trainees (3%) received a diagnosis of COVID-19 in 129 cohorts (49%). Among trainees with COVID-19 infection, 318 (79%) were men, and the median (interquartile range [IQR]) age was 20 (19-23) years; 204 (51%) were symptomatic, and 199 (49%) were asymptomatic. Median (IQR) cycle threshold values were lower in symptomatic trainees compared with asymptomatic trainees (21.2 [18.4-27.60] vs 34.8 [29.3-37.4]; P < .001). Cohorts with clusters of individuals with COVID-19 infection were predominantly men (204 cohorts [89%] vs 114 cohorts [64%]; P < .001), had more symptomatic trainees (146 cohorts [64%] vs 53 cohorts [30%]; P < .001), and had more median (IQR) symptoms per patient (3 [2-5] vs 1 [1-2]; P < .001) compared with cohorts without clusters. Within cohorts, subsequent development of clusters of 5 or more individuals with COVID-19 infection compared with those that did not develop clusters was associated with cohorts that had more symptomatic trainees (31 of 58 trainees [53%] vs 43 of 151 trainees [28%]; P = .001) and lower median (IQR) cycle threshold values (22.3 [18.4-27.3] vs 35.3 [26.5-37.8]; P < .001). Conclusions and Relevance: In this cohort study of US Air Force trainees living in a congregant setting during the COVID-19 pandemic, higher numbers of symptoms and lower cycle threshold values were associated with subsequent development of clusters of individuals with COVID-19 infection. These values may be useful if validated in future studies.

Examining Racial Disparities in Diabetes Readmissions in the United States Military Health System.

INTRODUCTION: Diabetes is one of the most common chronic conditions in the United States and has a cost burden over $120 billion per year. Readmissions following hospitalization for diabetes are common, particularly in minority patients, who experience greater rates of complications and lower quality healthcare compared to white patients. This study examines disparities in diabetes-related readmissions in the Military Health System, a universally insured, population of 9.5 million beneficiaries, who may receive care from military (direct care) or civilian (purchased care) facilities. METHODS: The study identified a population of 7,605 adult diabetic patients admitted to the hospital in 2014. Diagnostic codes were used to identify hospital readmissions, and logistic regression was used to analyze associations among race, beneficiary status, patient or sponsor's rank, and readmissions at 30, 60, and 90 days. RESULTS: A total of 239 direct care patients and 545 purchased care patients were included in our analyses. After adjusting for age and sex, we found no significant difference in readmission rates for black versus white patients; however, we found a statistically significant increase in the likelihood for readmission of Native American/Alaskan Native patients compared to white patients, which persisted in direct care at 60 days (adjusted odds ratio [AOR] 11.51, 95% CI 1.11-119.41) and 90 days (AOR 18.42, 95% CI 1.78-190.73), and in purchased care at 90 days (AOR 4.54, 95% CI 1.31-15.74). CONCLUSION: Our findings suggest that universal access to healthcare alleviates disparities for black patients, while Native America/Alaskan Native populations may still be at risk of disparities associated with readmissions among diabetic patients in both the closed direct care system and the civilian fee for service purchased care system.

COVID-19 Monitoring and Response Among U.S. Air Force Basic Military Trainees - Texas, March-April 2020.

The coronavirus disease 2019 (COVID-19) pandemic has resulted in substantial morbidity and mortality since it was first described in December 2019 (1). Based on epidemiologic data showing spread in congregate settings (2-4), national, state, and local governments instituted significant restrictions on large gatherings to prevent transmission of disease in early March 2020. This and other nonpharmaceutical interventions (NPIs) have shown initial success in slowing the pandemic across the country (5). This report examines the first 7 weeks (March 1-April 18) of implementation of NPIs in Basic Military Training (BMT) at a U.S. Air Force base. In a population of 10,579 trainees, COVID-19 incidence was limited to five cases (47 per 100,000 persons), three of which were in persons who were contacts of the first patient. Transmission of symptomatic COVID-19 was successfully limited using strategies of quarantine, social distancing, early screening of trainees, rapid isolation of persons with suspected cases, and monitored reentry into training for trainees with positive test results after resolution of symptoms.

Exclusion of left atrial appendage thrombus using single phase coronary computed tomography as compared to transesophageal echocardiography in patients undergoing pulmonary vein isolation.

Background. Transesophageal echocardiography (TEE) is used for the evaluation of the presence of left atrial appendage (LAA) thrombus prior to pulmonary vein isolation (PVI), while coronary computed tomography angiography (CCTA) is used for anatomic mapping during PVI. Methods. We compared the diagnostic performance of single phase CCTA to TEE in excluding the presence of LAA thrombus in patients undergoing PVI in 172 subjects performed during index hospitalization. Results. The mean age was 51 ± 13 years, a median CHADS2 score of 1 [IQR25,75 0,1, range 0-3] and a mean periprocedural INR of 2.1 ± 0.6. The prevalence of an LAA filling defect on single phase CCTA was 9.3% (6/183) and on TEE was 1.2% (2/183). Sensitivity, specificity, positive predictive value, and negative predictive value were 100% (95% CI, 19.8-100%), 91.8% (95% CI, 94-99%), 12.5% (95% CI, 60-76%), and 91.8% (95% CI, 97-100%) for the detection of LAA filling defect, respectively. Conclusion. Given the utility of a preprocedural single phase CCTA for the performance of PVI, the absence of a filling defect negates the need for a subsequent TEE as an adjunct for exclusion of LAA thrombus.