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.

Taking the health impact of economic factors seriously

If (or when) I tire of reading trite articles linking exposure A to outcome B while avoiding even a consideration of context or history, I turn to the International Journal of Health Services.  It is not the best-known journal around, and there are very few quick fixes and takeaway messages.  There are certainly no ‘What this study adds’ boxes à la BMJ stable.  Thank goodness.  The journal provides provocative and deep analysis of the current political and economic system and how it affects health.  Under the editorship of Vincent Navarro the journal has focused on critiquing the mainstream, and while I do not always agree with the views expressed, I always gain something from reading.

For example, the most recent issue contains at least four articles that are now high on my to-read pile.

  1. Nadine Nowatzki takes us down the well-worn path of the cross-national relationship between income inequality and mortality/life expectancy.  She focuses on wealth inequality (perhaps a more insidious form than income, since it is longer-lasting) and finds that while the overall pattern looks similar to that for income inequality, the ordering of nations differs.  Her discussion looks at a range of explanations, including social capital and redistributive policies across classes and the lifecourse.
  2. Carles Muntaner and colleagues continue to consider income inequality, explicitly engaging with Richard Wilkinson and Kate Pickett’s The Spirit Level.  They note that Wilkinson and Pickett focus on psychosocial explanations for the ill-health associated with greater inequality, and go on to challenge the authors on this.  Muntaner et al. prefer to focus on materialist explanations, specifically those which arise from social class in the form of exploitation (cf Erik O Wright), and this leads them to urge greater intervention in the economic structure of societies to improve health.
  3. Gavin Mooney moves us to more conceptual ground.  Mooney’s name is one I know from the Health Economics world, where he has been a careful and trenchant critic of the focus on efficiency over equity in that field.  Now it appears he has a new book out, focusing more on political economy and the impact of neoliberalism on health, and for which this paper is a taster.  The core of his argument (and please note I haven’t read the paper thoroughly yet) appears to be that the WHO and the Breton-Woods institutions (World Bank, IMF) have been co-opted into the global neoliberalist focus on individual rights over communitarian needs and approaches.  And that this has had serious negative effects on health.  Certainly an argument worth engaging with.
  4. Claudio Schuftan considers the links between poverty and broader human rights violations, not so much the direct links but rather the common causes.  She identifies the neoliberal governmental framework, religion and man-made disasters at the fulcrum of the system, driving the failure to implement UN (and other) conventions protecting rights and subsequent powerlessness and resignation amongst the powerless.  These then cascade into numerous direct causes of rights violations, but I’ll leave those for you to read about.  It’s certainly a strongly argued vision of the way the world works, and works to harm the most vulnerable.   This paper in particular, I would like to see linked up with Sen/Nussbaum’s capabilities approach.

All of which adds up to uncomfortable, but (indeed perhaps therefore) important, but never dull, reading.

Papers of the Week: 25/2012

Clearly much water (23 weeks worth, apparently) has passed under the bridge since I last posted on new papers crossing my rss/email desk.  So here are the latest batch:

  1. I am more than a little fascinated by the interplay of race, SES, gender and any other stratifier you can mention in determining infection risks.  And in the field of STIs, I appear not to be the only one.  One angle on this is to look at multiple low-power identities and see how they interact.  For example, here‘s a paper that focuses on the intersection of race/ethnicity and sexual orientation.  Risks definitely rise with multiple minority statuses, but the pattern is non-simple and varies by sex.  It’s never as simple as you’d think.
  2. More on concurrent partnerships in Africa.  A recent study found no association between (self-reported) concurrent partnerships and HIV incidence in rural South Africa and while it is generally accepted that concurrency can theoretically drive an HIV epidemic, empirical evidence remains scant that it does so.  One reason for this may be that while concurrency is risky, its prevalence is low.  This idea is supported by a paper out of Malawi from last year which finds that concurrency is long-lasting when it occurs, but that it occurs infrequently (only in 9% of the sample).  Lots more evidence is needed on this, but these are the right questions to be asking.
  3. This one is only “new to me”. Dynamic models of sexual relationships (and other contact networks, I think that sexual networks are simpler than most) need to be a big new field in ID Epi.  If that’s going to happen we (public health people) are going to need to read lots of network analysis stuff (aside: here‘s an intro from Nick Christakis and collaborator Kirsten P Smith (meta-aside: Smith’s disseration from Penn looks really interesting – international comparisons of STI rates, but I can’t see it published yet).  If you want more theoretical details, James Moody – one of the key people behind the Add Health network work mentioned in the above article – wrote a paper in Social Forces a decade ago, which outlines things nicely.  Beach reading, if I ever made it to the beach.  And enjoyed reading once there.

Next time I’ll try and make these papers a little more up-to-date, but this’ll have to do for now.

Potentially interesting papers: Week 51 2011

I had expected this week to be quiet, what with the upcoming festive season and all, but I was pleasantly surprised to find a few titbits to look over and decide ‘yes, I should definitely read this some time soon’.   Therefore, without further ado,  I present:

1.  A simple, yet elegant, study of the interplay of individual and national income in determining who volunteers to be tested for HIV (this paper has been around for a year or so it seems).  It looks like the positive income gradient seen within countries (more income = more testing) is less pronounced in richer countries.  The analysis uses individual income in within-country quintiles, which makes interpretation difficult.  As the authors suggest, one way to look at things is to see this as evidence for the need to focus on poorer people in poor countries.  Another angle would be to see this as evidence that there may be a positive but decreasing slope to the overall relationship internationally – i.e. there is a positive relationship up to some income threshold internationally, and then the relationship levels out.  Which would suggest that focus needs to be on poor people everywhere.  Either way, food for thought.

2. A recent paper on drinking and STI acquisition in the US has me thinking about the causal relationships around sex and drugs (and rock and roll) again.  The paper finds various alcohol-related activities in adolescence linked to various risky behaviours (non-condom use) and self-reported STIs in early adulthood.   The temporality of this relationship is clear, but the almost syndemic nature of the package of behaviours that goes with alcohol and sex – can I call it a lifestyle without implying too much or too little agency? – makes me loath to attribute any direct causal effect from the alcohol to the sex/STI.  Not that the authors of this piece are claiming this, but I remain very unclear on how we might make an impact on STIs through interventions on adolescent behavioural patterns.  Of course, this may just be me banging my ‘social epi’ drum, so you may wish to let me bang it in peace.

3. Here’s something from another field that interests me greatly, but I have never had the time to get into deeply enough.  This is a nice conceptual effort to link human and pathogen behaviour together in an Ordinary Differential Equations setup to consider the mitigating/conflagratory effects of the former on the later in studies of dynamic disease spread.  It doesn’t look too technical for the non-mathematicians amongst us, so might be worth a skim for thought-provocation, if nothing else.

Potentially interesting papers: Week 50 2011

This week I have three possibilities to tantalize you with, one of which I am immediately set against, but feel I should read.

1. This piece in AIDS Care worries me for two surface reasons.  First, the abstract suggests that it is a quantitative analysis of DHS data being published in AIDS Care, a journal I usually turn to for depth and richness, not number crunching.  But I would never write something off based only on this.  Of more concern is the line “Contrary to the public health literature, women of high SES were also vulnerable to HIV risk”.  I am pretty there is a large literature highlighting this relationship already, which leads me to question the level of background research conducted.

2. A reminder that prevention interventions are acutely context-dependent.

3. I find it strange/disturbing how infrequently we consider the disease context of a community in measuring risk factors for HIV across large areas.  This paper from Zimbabwe, via UNC Chapel Hill, is a nice reminder of the importance of cross-level interactions.

Disclaimer. These posts are based on my reading of titles and abstracts, and all papers may be of much greater/lesser interest/quality than I have concluded based on reading 200 words or fewer.

Interesting titles this week – an introduction

So, as you (the reader, singular), may have noticed there hasn’t exactly been a bunch of new material on this site recently.  You can blame quals (I know I do).  In order that I don’t completely let this blog lapse into the senility it most certainly deserves, I began to search around for material to post that wouldn’t require an hour or two of prep and any kind of serious mental effort.  This is the result.

I currently get three sets of emails a week that remind me of how damn productive my particuar niche(s) of the academosphere are.  One is from the amazing and prodigious Robert Malow.  The sheer quantity of material that this man works through is amazing, and then he formats it up nicely and emails it to very many people around the world.  The topic is HIV, but within that this biweekly publication covers everything from the molecule to society.  And it’s free.

The other two are non-curated emails, one from Google Scholar and the other from PubMed.  The former is entirely based on keyword searches, which makes narrow searches or multiple terms a necessity – especially since it often picks up grey literature.  The latter allows you to use fields to narrow searches down – if you are not already using these generally, and MeSH terms specifically, you are seriously underutilizing the strengths of PubMed.

These three updates provide high sensitivity, but pretty low specificity, and I then use a sophisticated algorithm (a.k.a. The Eyeball Test) to pick out potentially interesting things to read properly.  It is from this two-step procedure that I found all the articles I have blogged about so far, and probably those I will in the future.  But I will never get to blogging about half/98% of those I pick.

My plan, therefore, is to post every week a list of the things I have picked up, but not necessarily yet read.  Partly I hope that this will be of interest, if your interests are very closely aligned to mine (hence the singular reader concept), and partly I hope that this will push me to actually read them myself.  So a win for everyone, possibly.