What’s new in Ebola research: October 2015

Another round-up of new publications on Ebola, primarily items first put out in public in the month of October 2015. This is largely a list, with a little light curation and commentary.  Comments, missed items and disagreements welcome.

A. Clinical epidemiology

Papers this month highlight how Ebola differentially affects healthcare workers, children, mothers and infants and survivors and their sexual partners.

Epidemiology of Ebola virus disease transmission among health care workers in Sierra Leone, May to December 2014: a retrospective descriptive studyOlushayo Olu and MoH/WHO colleagues interviewed 293 infected healthcare workers and found the main (presumed) locations of infection to be the workers’ homes and non-Ebola healthcare settings. Over one-third of infected HCWs reported not having been trained in infection prevention/control pre-infection.

Did Ebola relatively spare children? Stephane Helleringer and colleagues cast some doubt on previous estimates that children had lower Ebola incidence rates than children, noting age-specific differences in: (i) historic health-seeking behaviour; (ii) speed of disease progression; and (iii) identification as contacts of infected individuals, each of which may have led to selective underreporting.

Ebola viral disease and pregnancy. Benjamin Black and colleagues review the many complications of pregnancy and birth for women infected with Ebola, including the absence of any recorded neonatal survival, potential for transmission perinatally to healthcare workers and ongoing risk from breast milk which may be infected. The authors suggest a focus on maternal support, given the very low probability of child survival.

Ebola RNA Persistence in Semen of Ebola Virus Disease Survivors — Preliminary Report. Gibrilla Deen and colleagues analysed one-off semen from 93 Ebola survivors, finding RT-PCR positive results as late as 9 months post-infection: although there was a notable fall-off in detection probability after 5 months. Crucially, the authors note we do not know how RT-PCR positivity is associated with virus infectivity.

Molecular Evidence of Sexual Transmission of Ebola Virus. Suzanne Mate and colleagues present genomic evidence to support the claim that the last known Ebola infection in Liberia (in March 2015) was infected via sexual transmission from an Ebola survivor six months post-disease onset.

Not a published paper yet, but Miles Carroll and colleagues presented ongoing work that suggested a woman had acquired Ebola antibodies without apparently ever contracting the virus. This could be very important for understanding both individual immunity, and evidence that a minority of those living in West Africa had Ebola antibodies prior to 2014. This was part of a larger body of work studying Ebola infected survivors and close contacts of infected individuals.

B. Non-Ebola impact of the epidemic

Papers this month include the past and continuing impact of Ebola on those giving birth, TB, measles, the healthcare system as a whole and GDP.

A case series study on the effect of Ebola on facility-based deliveries in rural LiberiaJody Lori and colleagues show the rapid fall-off in use of maternal waiting homes as Ebola advanced in the middle of 2014 in Bong county. Impact on MCH.

Ebola, fragile health systems and tuberculosis care: a call for pre-emptive action and operational research. Rony Zachariah and colleagues highlight the potential spillover of the Ebola epidemic in affecting tuberculosis control efforts in affected countries, due to repurposing or mothballing of TB resources, fear of healthcare generally and loss of healthcare staff to Ebola. The authors highlight the lack of research into the impact of Ebola on TB to date.

Mitigating measles outbreaks in West Africa post-Ebola. Shaun Truelove and colleagues are not the first to point out the risk of re-emerging infectious diseases in the countries most affected by Ebola (see also, TB, malaria, maternal and infant health, nutrition, etc).  Their editorial, however, does point to the need to fill gaps left by the Ebola epidemic, and to leverage systems set up for Ebola to fight the potential wave of post-Ebola health issues.

Impact of the Ebola outbreak on health systems and population health in Sierra Leone. James Elston and colleagues highlight (using both quantitative and qualitative methods) the multiple ways in which the Ebola epidemic has led to a loss of trust in the healthcare system in Sierra Leone, even as the epidemic has waned, and the need for investment in rebuilding the system and engagement between community and healthcare providers.

Indirect costs associated with deaths from the Ebola virus disease in West Africa.  Joses Muthuri Kirigia (at WHO AFRO) and colleagues calculated the future loss of GDP due to productive years of life lost from Ebola morbidity and mortality. They estimate that the three most-affected nations will lose approximately I$ 150m from this epidemic due to non-health GDP losses.

 C. Operational research

A range of topics here: three evaluations of epidemic responses – contact tracing, healthcare workers as infection vectors, treatment beds as prevention – as well as estimates of epidemic underreporting and variation in numbers of secondary cases created by those infected.

Contact Tracing Activities during the Ebola Virus Disease Epidemic in Kindia and Faranah, Guinea, 2014Meredith Dixon and colleagues highlight the limited capacity of contact tracing to find cases before they became symptomatic in Guinea in late 2014.

Role of healthcare workers in early epidemic spread of Ebola: policy implications of prophylactic compared to reactive vaccination policy in outbreak prevention and controlCordelia Coltart and colleagues highlight the potential benefits of inoculating healthcare workers in at-risk settings with any Ebola vaccine that proved to provide long-lived immunity: not just in terms of maintaining a motivated and healthy workforce during any future outbreak, but also as a means of dramatically reducing take-off of infection chains – based on evidence from past outbreaks.

Measuring the impact of Ebola control measures in Sierra LeoneAdam Kucharski and colleagues highlight (via a mathematical model) that the exact timing of effective control measures (specifically the expansion of treatment beds) in late 2014 had a huge impact on the total number cases and deaths seen – since it altered the whole trajectory of the epidemic.

Use of Capture–Recapture to Estimate Underreporting of Ebola Virus Disease, Montserrado County, Liberia. Etienne Gignoux and colleagues at MSF triangulated data from Ministry of Health case investigation records and ETU records from June to August 2014, to estimate that three-quarters of all cases in this period were unreported.

MERS, SARS and Ebola: The role of super-spreaders in infectious disease. Gary Wong and colleagues highlight the importance of heterogeneity in numbers of cases caused by each infectious person in Ebola, as in key emerging respiratory infections over the past few years.


D. Miscellanea

Each of the issues raised below is important, I just could not easily find a theme under which to categorize them.

Effectively Communicating the Uncertainties Surrounding Ebola Virus Transmission. Andy Kilianski and Nicholas Evans draw on academic literature debating the possibility of airborne Ebola at the peak of the epidemic to highlight the importance of making claims with clear markers of uncertainty of evidence and relative likelihood of competing hypotheses, for the good of both the research community’s reputation and the public’s future health.

Beyond Ebola Ethics: Do Nurses have a Duty to Treat? Miriam Walter explores the duty of care that nurses and other healthcare workers may have to patients of highly virulent or infectious diseases, such as Ebola, and whether society has the legal or moral right to require such service. No easy answers, but a thought-provoking read.

The Ebola response in West Africa Exposing the politics and culture of international aid. Marc DuBois and colleageus at the ODI have compiled a report looking at the humanitarian aid system in light of the Ebola outbreak. The authors are damning, but not in a blanket manner, and highlight the importance of political rather than technical changes in achieving better results in the future.

Annotated Ebola lit list: September 2015

In the interests of not letting perfect be the enemy of halfway decent, I am finally putting something new up on this blog. Unlike the past monographs, this will (hopefully) be the first of a series of monthly bullet-point posts on new articles that caught my eye. Clearly this will not be as “real time” as Twitter, etc, but it might just help you keep up with what is new-ish in Ebola research.

Note: This list will be heavy on epidemiological matters, moderate on clinical/operational and light on basic science. If we are really lucky, I might even add some commentary to link them together. Maybe.

A. Mathematical epidemiology

  1. Characterizing Ebola Transmission Patterns Based on Internet News Reports. Julie Cleaton and colleagues compared Ebola epidemic parameters derived from news reports with those estimated from epidemiological models, running up to February 2015. Media-based estimates were higher, but not qualitatively different from, those from more traditional sources.
  2. Modeling contact tracing in outbreaks with application to Ebola. Cameron Browne and colleagues explore how the effective reproductive number is affected contact tracing. A theoretical paper applied to Ebola as a test case.
  3. Modeling household and community transmission of Ebola virus disease: epidemic growth, spatial dynamics and insights for epidemic control. Maria Kiskowski and Gerardo Chowell build a three-scale network (individuals, households, communities) that structures contacts and thus disease spread. The authors highlight that the network structure slows and structures epidemic spread in predictable ways
  4. The velocity of Ebola spread in parts of west Africa. As an timely complement to Kiskowski’s paper, Kate Zinzer and colleagues at Healthmap show how fast Ebola actually spread geographically from its presumed ground-zero in Guéckédou across the three most-affected countries. Apparently, the answer is, an average of 19.3km/week.
  5. Decreased Ebola Transmission after Rapid Response to Outbreaks in Remote Areas, Liberia, 2014.  Kim Lindblade and large CDC team evaluated the evolution of the reproductive number following a complex anti-Ebola intervention (case isolation, contact tracing/monitoring, behaviour change messaging) in rural Liberia from July 2014 onwards. The team show a huge drop in R0 from 1.7 to 0.1, largely driven by a 90% drop in secondary infections for patients admitted to ETUs. ETUs also halved mortality risk.

B. Social Epidemiology

  1. Ebola epidemic exposes the pathology of the global economic and political system. David Sanders and colleagues consider the political economy of the Ebola outbreak, including employment patterns, healthcare systems and the WHO, with the International Journal of Health Services’ signature focus on the political.
  2. Social Vulnerability and Ebola Virus Disease in Rural Liberia. John Stanturf and colleagues estimated a multidimensional Social Vulnerability Index at the Liberian district level, and compared results to Ebola outbreak figures across the country.

C. Operational practice

  1. Ebola Virus Diagnostics: The US Centers for Disease Control and Prevention Laboratory in Sierra Leone, August 2014 to March 2015. Mike Flint and many colleagues describe the CDC’s laboratory setup, processes and throughput in Bo.
  2. Remote Sensing of Vital Signs: A Wearable, Wireless “Band-Aid” Sensor With Personalized Analytics for Improved Ebola Patient Care and Worker Safety. Steven Steinbul and colleagues present a wireless sensor for Ebola patients that allows continuous monitoring without infection or fatigue (i.e. from PPE) risk for healthcare workers. The “MultiSense” was in field tests in July 2015.