Links to new research on Ebola: June 2016

The last hurrah. New material from June 2016. From here on, good luck and I look forward to skimming the literature from time-to-time without posting it up here.

Therapeutics and Vaccines

Epidemiology

Epidemic control strategies

There were also a couple of more conceptual modelling papers this month:

Survivors

Health care for Ebola

Ebola epidemic impact

Other items

That’s all folks, thanks.

Links to new research on Ebola: May 2016

Yes, this is late. Sorry. But here’s all the new stuff I saw in May of this year:

Therapeutics and Vaccines

Epidemiology

Epidemic control strategies (mostly models)

Ebola healthcare

Survivors

Impact of Ebola on other things

Other items (mostly trying to understand what went wrong)

One more month of material to come…

Links to new research on Ebola: April 2016

As ever, tempus fugit. I have finally accepted I will not be keeping up with the Ebola literature any time soon. So I am posting three more lists of links, covering April, May and June of 2016, and then leaving you all to run your own PubMed and GoogleScholar alerts (I set mine for delivery weekly and whenever Google wants to send me something respectively). After that, it is back to occasional posts on the social determinants of HIV, TB, etc (i.e. my day job). It has been a privilege learning so much about an awful outbreak and the phenomenal efforts made by so many to fight it. Thank you for dropping by and motivating me to stay focused, and sometimes even up-to-date.

First up, things indexed in April 2016.

Therapeutics and Vaccines

Epidemiology

Epidemic control strategies

Health care for Ebola

Ebola epidemic impact

Survivors

Other items

Links to new research on Ebola: March 2016

And part II of my attempts to get up-to-date, research that came out in March.

Therapeutics and Vaccines

Epidemiology

Epidemic control strategies

Health care for Ebola

Ebola epidemic impact

Survivors

Other items

Links to new research on Ebola: February 2016

Many apologies for the long radio silence.  I have, unfortunately, not had time to build proper summaries over the past few months.  But rather than leave my initial work to fester, I am putting up these unadorned lists of links, in case others find them to be of use. Starting with materials from February.

Epidemiology

Epidemic control strategies

Health care for Ebola

Ebola epidemic impact

Vaccines

Survivors

Other items

 

 

 

New research on Ebola: January 2016

A shockingly on-time update, covering all the material on Ebola epidemiology and proximate topics that’s new to me in January.  As ever, please let me know if I’ve missed or mis-interpreted something.

 

A. Clinical epidemiology and health systems

Xudong Gao and colleagues highlight a range of symptoms seen to be predictive of diagnosed Ebola, and of mortality, in 773 suspected cases admitted to Jui hospital in Freetown: vomiting, diarrhoea, weakness, loss of appetite, conjunctivitis, hiccups, and confusion. The authors note that rapid, specific diagnostics would still be preferable.

A couple of papers considered survival predictors. The WHO Ebola Response Team highlight a couple of key gender differences in the >20,000 cases seen in the West African epidemic, based on individual-level data: first, women reached treatment facilities an average of 12 hours earlier following symptom onset; and second they were some 15% less likely to die (63% vs 67%), even after adjusting for various potential confounders. Samuel Crowe and colleagues provide evidence from Bo District in Sierra Leone that symptomatology at facility admission was not associated with survival, but first PCR cycle threshold (a proxy for viral load) was predictive of survival at a cutpoint of 24.

There is also more on Ebola survivors. Abrar Chughtai and colleagues review the 12 published papers (to October 2015) on EBOV in convalescent patients’ body fluids. Viral RNA has been found in urine, aqueous humor, sweat, semen, vaginal secretions, breast milk, faeces and conjunctival fluid up to 9 months post-recovery; EBOV itself has been found in semen, aqueous humor, urine and breast milk. There are also two recent additions to this literature this month. John Chancellor and colleagues provide a detailed case description of a returning US doctor who survived EVD and his subsequent ophthalmologic complications. Helena Nordensted and colleagues report a case of a lactating mother who was admitted to care testing positive for EVD in her breast milk. The authors could neither tell whether virus was transmissible via milk, nor whether it lasted beyond EVD clearance from the woman’s blood, but this will add another way in which Ebola might be spread. Anna Thorson and colleagues review the literature specifically on sexual transmission, highlighting positive RNA tests up to nine months post-recovery in semen, and recommending condom use in the absence of abstinence (although no study of condom effectiveness for EBOV prevention yet exists).

Several other papers present research on healthcare-related topics. Two papers consider treatment protocols during the Ebola outbreak. Emmie de Wit and colleagues examine the feasibility of PCR testing for malaria in parallel with Ebola PCR testing. They note that even though presumptive antimalarial treatment was given for any febrile illness, the marginal resource cost of PCR malaria testing was minimal, and it might help with treatment plans. Indi Trehan and colleagues present the paediatric management protocols for Maforki ETU in Port Loko, Sierra Leone, including how they evolved over three months of use between December 2014 and March 2015.

Jianping You and Qing Mao describe the architecture of the Chinese-built ETC in Monrovia, and its strengths and weakness compared to more temporary structures. Abdoulaye Touré and colleagues report on HCW knowledge, attitudes and practices in Conakry, showing high levels of knowledge about Ebola symptoms and transmission risks, but also a preponderant belief that they did not know enough about the disease. Ibrahim Bundu and colleagues describe the rapid and almost-complete fall-off in surgical activity at Sierra Leone’s main teaching hospital in August 2014 as the Ebola epidemic took off in Freetown, and point to key lessons for surgery in future similar outbreaks. Similarly, Catherine Cooper and colleagues describe the development of infection prevention and control (IPC) guidance in the face of the Ebola epidemic and highlight the importance of sector-wide coordination and in-place national protocols in advance of future epidemics.

 

B. Diagnostics, Therapies and Vaccines

On the diagnostic front, following up from last month’s clutch of papers on the Xpert Ebola assay, Rafael Van den Bergh and colleagues review the field-effectiveness of the test in Guinea. The authors report a halving (from 334 to 165 minutes) of time to results compared to PCR, with no false-negatives amongst 218 tests for the Xpert system; they recommend Xpert as an improvement of current standard of care.

There is also an incredibly rich set of papers up this month, from a special issue of Clinical Trials (Pubmed hack, no direct link yet) curated by Lori Dodd and covering trial designs. I have only scratched the surface of the 19 research and perspective articles, but can already recommend it to the more statistically minded amongst you. Hopefully I will one day have a hard-copy of this on my shelf for dipping into. Several of the Clinical Trials articles touch on the ethics of study designs, and in a separate article Annette Rid and Franklin Miller review the ethical rationale for the Ebola ça Suffit ring vaccination trial, highlighting that although it attempted to avoid leaving participants in a placebo arm, it remained a research study – rather than a vaccine rollout operation.

Emelissa Mendoza and colleagues review the evolution of testing therapeutic candidates during the West Africa outbreak, with detailed descriptions for Amiodarone, Brincidofovir, Favipiravir, convalescent plasma and TKM-Ebola. Mendoza et al. were upbeat about convalescent plasma, however Johan van Griensven and colleagues report no significant impact of such plasma on survival in an 84-person non-randomized trial using historical controls. (van Griensven’s team also has a paper in the Clinical Trials special issue on how this analysis was designed.) Researchers may now focus on more concentrated forms of plasma.  On another tack, Stephen McCarthy and colleagues searched for existing drugs that have antiviral activity against Ebola, identifying Interferon-\beta and combinations of various other drugs as candidates.

 

C. Epidemic dynamics and prevention

There were a grab-bag of modelling and field-methods papers this month:

  • Mosoka Fallah and colleagues http://annals.org/article.aspx?articleid=2480063 detail the setup of a community-based initiative model in Liberia, and its impact in West Point, a low-income, highly affected neighbourhood of Monrovia. This need for community engagement is echoed in a paper by Samuel Cohn and Ruth Kutalek, which shows parallels between community resistance to external control measures for Ebola and that seen for European Cholera outbreaks in the 19th century.
  • Tom Koch provides a detailed overview of various approaches to mapping both human and physical geographies, and suggests how such methods might inform future outbreak responses.
  • Alessandro Rizzo and colleagues present a neat agent-based model of Ebola dynamics that allows for changes in individuals’ contact networks following infection, and more rapid removal via the implementation of behaviour change interventions. The authors reach similar conclusions to previous modelling studies, but with the benefit of added realism that may be crucial for some questions.
  • Eva Santermans and colleagues built an instructive two-part model of the West African epidemic using publically available data: first, a spatio-temporal regression model to understand how infections spread across districts; and second a state-transition model to understand growth within districts. The authors propose such methods for real-time outbreak monitoring and prediction.

 

D. Miscellenea

As ever, there are a few articles that I cannot neatly shoehorn into categories; as ever, this reflects my shortcomings, not the relative importance of the work.

  • First, the Pan-African Medical Journal devoted its October 2015 issue to Ebola in West Africa, with a range of articles covering Nigeria, Senegal and Ghana, in addition to the three most-affected nations.
  • Second, Solomon Benetar outlines three levels of ethical responsibilities in the Ebola outbreak: interpersonal, public health and global.
  • Third, South African clinicians Rosie Burton and Tom Boyles reflect on their experiences working in Liberia and Sierra Leone.
  • And finally, Eugene T. Richardson and colleagues conduct a biosocial analysis based on four interviews with Ebola survivors in Kono District, Sierra Leone, highlighting political, economic, ecological, and cultural factors that led to the distribution of Ebola infection seen globally over the past three years.

 

New research on Ebola: December 2015

The holidays seem to have cast their pall over my productivity, so this post is emerging three weeks late.  Hopefully January’s will be a little prompter.  As ever, do let me know if I’ve missed/misinterpreted anything important.

Epidemic dynamics

First up, Jean-Paul Chretien and colleagues take on the monumental task of reviewing all 66 Ebola modelling studies from the past 18 months. Chapeau! They highlight variability in methods and approaches and call for best practice guidelines for future outbreaks.

At the national level, Jason T. Ladner and colleagues use genomic analysis of 140 Liberian genomes to show that almost all cases of Ebola in Liberia most-likely all came from a single introduction – probably from Sierra Leone. Given the importance of intense personal contact, models reflecting network structure are often informative.  Anca Radulescu and Joanna Herron investigate the implications of community structures (internal and external, static and dynamic) for key quarantine choices (e.g. focus on breaking local or global ties), and in turn of these choices on epidemic spread. Also at the community level, Mosoka Fallah and colleagues use a stochastic model framework populated with individual-level data on cases in Montserrado county, Liberia – including contact tracing information on a subset – to suggest that the poorest communities were not only the most affected areas, but also most likely to spread infection elsewhere. Moving down to the household level, Ben Adams builds a household-structured model of a population, and shows the importance of larger household sizes in increasing initial growth rates, the basic reproduction number and the household reproduction number (how many within-household infections the average infectious person causes).  If, as seems likely, poorer households are larger households, then the Adams and Fallah papers may be approaching the same issue from different angles.

Patient-level epidemiology

Several papers in December reported on the clinical profile of the epidemic, and how this affected patient outcomes. Oumar Faye and colleagues reviewed viremia data at hospital entry for 699 patients around Conakry up to February 2015, showing that a one-log higher baseline viremia was associated with a 14% reduction in survival probability.  Samuel Crowe and colleagues showed that amongst patients in Bo District, Sierra Leone, time from symptoms to hospital admission was not associated with mortality risk, but viral load at first testing was.  JY Wong and several colleagues reviewed line-list data on all confirmed, probable and suspected Ebola cases in Sierra Leone up to the end of January 2015.  In addition to the typical inverted-u mortality curve associated with age, the authors found no increased mortality risk for women, or for healthcare workers.  Finally, Stefano Petti and colleagues noted, based on a systematic review, that the West African Ebola outbreak showed very different haemorrhagic symptoms to earlier outbreaks – notably a two-thirds drop in bleeding from gums and a tenfold drop in bleeding from the eyes and nose. It is unclear if these changes reflect host, agent or environment (e.g. healthcare) differences.

On the paediatric front, and linked to an earlier suggestion by Benjamin Black and colleagues to focus on maternal health for pregnant women with Ebola ), JM Nelson and colleagues review all published data on live births to Ebola-infected mothers since 1976, showing that all 15 known neonates died with 19 days of birth (although I believe that there is now one longer infant survivor – the last Guinean survivor in the initial outbreak). On a similar topic, Séverine Caluwaerts and colleagues report two cases of pregnant women who recovered from Ebola, but delivered stillborn babies approximately one month post-recovery with EVD in the amniotic fluid. As well as having obstetric implications, these cases suggest yet another reservoir for Ebola post-recovery.

On an operational note, F Vogt and colleagues review MSF’s triage system for admitting suspected Ebola cases in Kailahun to suspect or highly suspect wards in advance of confirmatory tests, based on positive contact history and one other relevant sign/symptom.  They find PPV, NPV, sensitivity and specificity for confirmed cases were all below 76%. Given the high risk of nosocomial infection, the authors recommend single compartments where possible, and the swift implementation of any point-of-care rapid test available. Similarly, Cristina Carias and colleagues evaluated the cost-effectiveness of providing malaria prophylaxis to Ebola case contacts, to avoid malaria and thus false-positive admissions of these contacts to ETUs. Their analysis showed cost savings based just in terms of the cost of admission/bed-stay at the ETUs, although there is also potential benefit of avoiding infection with Ebola, and of sending those with malaria (especially children) to ETUs unable to manage malaria treatment (as highlighted by an article by Gillian McKay on the ethical dilemmas of field triage for malaria/Ebola).

Vaccine and treatment trials

A common message as the West Africa epidemic wanes is that we do not know all that much more about what works in terms of products than we did two years ago. Jon Cohen and Martin Enserink provide two succinct summaries [online article, Magazine version] of the 13 clinical treatment and vaccine trials run to date, noting that only the Guinea Ebola, ca suffit! Ring vaccination trial has shown a clear benefit and had been published by the end of 2015.  Anton Camacho and colleagues provide a model that shows one reason for this dearth of evidence, showing that trials begun in the context of a waning epidemic – in this case Forécariah prefecture in Guinea, beginning in mid-2015 and enrolling 100,000 – are often doomed to failure. One reason for the delay in rolling out trials was uncertainty about the correct way to balance various ethical criteria. Francis Kombe and colleagues discuss the ethical considerations and deliberations that arose in planning a convalescent plasma trial, highlighting the need to provide access even to those typically considered vulnerable and excluded from trials (children; pregnant women), and to provide supportive services to both donors and recipients.

Diagnostics

In contrast to treatments, there appears to have been some progress in developing rapid, point-of-care Ebola tests. Pierre Nouvellet and colleagues review rapid tests for Ebola already available and under development, and use mathematical models to suggest that the earlier isolation they might have allowed could have reduced case numbers by a substantial amount. Meanwhile, Petrus Jansen van Vuren and colleagues, and Benjamin Pinsky and colleagues provide lab evidence of Cepheid’s GeneXpert Ebola PCR test working within 90 minutes. At a conference in late October 2015, Amanda Semper and colleagues showed 100% sensitivity/specificity for the same test in field laboratory setting in West Africa.

Prevention

Less this month on behavioural interventions. Umberto Pellecchia and colleagues used qualitative interviews and discussions to flag the importance of local engagement in epidemic management.  Their work highlighted tensions within communities in Liberia as they negotiated the Ebola outbreak, notably the economic strains of forced quarantines and (bribable) cremation teams, and the effectiveness of local ownership over behavioural interventions and enforcement. On a different tack, Jillian Sacks and colleagues described the process of developing, rolling out and troubleshooting an mHealth solution for electronic data collection by contact tracers in Guinea.

Survivors

As the epidemic splutters out, increasing focus is turning to the health sequelae of infection. In an important piece for planning for possible future outbreaks, Rosalind Eggo and colleagues combined temporal EVD survivor data with evidence that virus can remain in semen for up to nine months for some men, to estimate how the number of potentially-infectious men might evolve over the next few months.  The authors show that the numbers are low and likely to have fallen to a handful by the end of 2015. Malcolm Hugo and colleagues highlighted the need for ongoing psychological assessment and support for Ebola survivors.  Amongst 74 discharged individuals, experiences of death, family member loss and arousal reactions were common; one-third faced stigma in their communities and one-fifth pre-PTSD-type reactions one month post-discharge. John Mattia and colleagues reviewed early data (March/April 2015) from the Port Loko Ebola survivors clinic, finding joint pain (76%) and novel eye symptoms (60%) to be very common; the latter were highly associated with acute Ebola viral load.

 

New research on Ebola: November 2015

A summary of research on Ebola newly published in November 2015. I’ve tried to make this round-up flow a little better.  Hopefully the dots are a bit more joined-up.

Patient-level Epidemiology

The association of Ebola infection and mortality with age, viral load and other risk factors.

Several researchers focus on the age structure of this Ebola outbreak. Jin Li and colleagues describe the clinical outcomes of 288 confirmed Ebola patients at Jui hospital from October 2014 to March 2015. The authors again highlight the tight association between viral load and mortality, as well as increasing mortality for those aged over 18 and again over 40.  This pattern was also reported by Marc-Antoine de La Vega and colleagues. Alicia Rosello et al. review all seven past outbreaks of Ebola in the Democratic Republic of the Congo using line-list data. The authors show incident cases are overrepresented amongst those aged 25-65 – perhaps reflecting nosocomial and burial-based transmission routes – with higher mortality amongst the under 5s and over 15s. More severe epidemics appear to have been controlled faster. In a letter, Leslie Libow highlights the relatively low incidence rate of Ebola amongst under 18s in both the 2014 West African and 1976 Zaire outbreaks; Libow focuses on age-specific biological risk factors, however for me this highlights once again the importance of involvement in caregiving as a risk factor for Ebola infection.

Two papers in the same journal delve into the association between EVD viral load and patient outcomes. Marc-Antoine de La Vega and colleagues show that amongst the 632 fully-documented cases of Ebola seen at the MSF hospital in Kailahun between July and November 2014, mean initial viremia of survivors was over 100 times lower than that of non-survivors, and mean viral load fell by a factor of 10 from August onwards, at the same time as Ebola-specific antibodies became more common in the population. Simone Lamini and colleagues provide additional evidence from the Emergency ETC in Freetown, moving beyond initial viral load to show levels decline rapidly 4-5 days after symptom onset in survivors, but remain substantially higher amongst those who subsequently die. Finally, Julii Brainard and colleagues conduct a systematic review of filovirus risk factors, and highlight that that only one-third of those who had direct physical contact with an infected household-member became infected; they show low risks for several other behaviours, reminding us that these diseases are thankfully relatively difficult to transmit in many circumstances.

And in a case study, Angela Dunn and colleagues describe how the admission of two individuals infected with Ebola into general medicine wards led to seven secondary cases due to limited use of PPE – highlighting the importance of careful screening and precautionary use of PPE during Ebola outbreaks.

 

Epidemic dynamics

How disease spreads through populations

There are two new, national-level descriptive studies of the evolution of the epidemic. Adriana Rico and colleagues provided a detailed description of the evolution of the Guinea epidemic in and around Conakry up to March 2015, exploring possible mobility and healthcare-related explanations for the continuation of transmission in this area even after infections had ended in much of the rest of the country. Tolbert Nyenswah et al. provide an overview of the Liberian epidemic, its control and its implications, highlighting the importance of a centralized management system at the national level.

Researchers are increasingly engaging with the networked nature of Ebola spread, both theoretically and empirically. Mark Burch and colleagues built a Bayesian model for the co-evolution of outbreaks and contact networks, and applied it to the 2014 DRC Ebola outbreak. Within Sierra Leone, Wan Yang and colleagues build an adjusted “gravity” model – which assumes closer, denser districts had more movement between one-another – to infer how infections passed between the 14 districts of the country. It will be interesting to see how these results compare to phylogenetic connections once all the samples are in. Marco Ajelli et al. reconstruct the transmission chain for 49 Ebola cases in one Sierra Leone district – Pujehun – by merging field and hospital notes with HCW and community interviews. The authors generate a wealth of empirical epidemiological data and highlight the role of high detection, isolation and rapid burial in controlling the local outbreak.

The effectiveness of interventions

Linked to the work on viremia (above), two more papers address the importance of detecting and isolating cases early – preferably pre-symptoms – to control Ebola epidemics. Diego Chowell and colleagues model the benefits of detecting pre-symptomatic individuals (e.g. systematic PCR testing of case-contacts), while GF Webb and CJ Browne provide similar evidence focused on very early symptomatic cases.

Contact tracers are central to early case identification, and Ashley Greiner and colleagues interviewed Ebola contact tracers in six affected West African nations in late 2014 to understand how they succeeded in following transmission chains. The article highlights many barriers (notably fear, stigma and community mis-perceptions) and some useful strategies for combating them.

Philippe Calain and Marc Poncin consider the ethical dimensions of interventions, exploring the moral basis for quarantine and isolation in the context of Ebola. The authors highlight that, even given evidence of effectiveness, such measures may be morally questionable and potentially counterproductive, if individuals and communities are coerced into compliance.  Umberto Pellicchia and colleagues at MSF provide empirical evidence for exactly such counterproductive effects: showing how top-down quarantine procedures and enforced cremations in Liberia generated stigmatization of – and resistance by – poor Ebola-affected communities, exacerbating existing social inequalities.

Health communication – including messages to induce cooperation – was central to combatting the epidemic. Mauricio Duque-Arrubla outlines in his Masters thesis how messaging in Sierra Leone shifted with phases of the epidemic, moving from top-down to bottom-up as the need shifted from nationwide action to local implementation. The author highlights the need for constant re-evaluation and engagement with community, community leaders and government via a mix of strategies to maximize effectiveness.  Joachim Allgaier and Anna Lydia Svalastog frame the spread of health messages as being in competition with the spread of disease, and of unreliable/harmful information. The authors note that combination prevention efforts include the management of all of these spreading processes.

Within Ebola treatment centres, Adam Potter and colleagues pinpoint how personal protective equipment (PPE) led to heat strain, and provide practical guidance on work/rest timings given specific types of PPE and temperature/humidity.

And finally, Adam Kucharski and colleagues link together networks, interventions and vaccination programmes – in simulating an Ebola outbreak over a network-structured population using observed contact data. The authors show that while ring vaccination can help control an epidemic in concert with other interventions (i.e. behaviour change, active case finding, isolation), such a vaccination method relies on strong knowledge of existing transmission chains. Ebola vaccination strategies therefore need to take account of the epidemic and response context in determining the most efficacious and efficient approach.

 

Miscellanea

No less important than the papers covered above, but my powers of synthesis are insufficient to fit these into another catgegory.

  • Tara Smith outlines the strengths of using the West Africa Ebola outbreak to teach a cohesive and comprehensive course on global health.
  • Marc-Antoine de La Vega et al. review the evolution of the Ebola virus over the past 40 years, noting a relatively stable evolution and a lack rapid change over time.
  • P Loubet and colleagues show how the number of patients attending two HIV clinics in Monrovia dropped – and the level of follow-up delays rose – as the epidemic raged in 2014, highlighting the impact of Ebola on yet-another aspect of the healthcare system.
  • Kai-Lit Phua considers how risk factors acting at many different levels (host, agent, physical , health policy/funding and social/cultural environments) combined to increase the difficulty of turning the epidemic tide, and how a combined approach to addressing such factors might improve the chances of doing so – both now and in future epidemics.
  • A need for WHO and the world health system to reform has been highlighted by many in light of the Ebola epidemic. The Harvard-LSHTM Independent Panel on the Global Response to Ebola reported this month, and provided wide-ranging recommendations on what is needed to ensure a timely, joined-up response to future health crises; the hard part is bringing together those with power to make these changes, and persuading them to do so.   On the research policy front, the WHO and many major journal groups put out a statement on standards for sharing data in health crises – a common concern during the epidemic has been unshared data at the epidemiological and molecular levels.

 

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 study. Olushayo 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 Liberia. Jody 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, 2014. Meredith 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 control. Cordelia 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 Leone. Adam 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.