Next Friday, I will be attending the following conference:
There is going to be a great line up of speakers, including Paul Farmer, Atul Gawande, Dean Jamison, and others. Send me a note if you are also going to be there.
The conference was sold out for a while, but I have heard that they have opened up more slots to accommodate the additional demand (sign that this topic is finally starting to get some traction?). There were student rates available as well.Share on Facebook
An interesting phenomenon in the HIV epidemic is that among African couples where at least one member is infected with HIV, in nearly two thirds of the cases only one member is actually infected – that is that there is a very high prevalence of “serodiscordance”. Serodiscordance can happen when transmission has not yet occurred between new couples or in a stable relationship when one partner acquires the virus elsewhere an introduces it into the relationship (for example if one member is cheating). Transmission of virus within existing couples is an important source of new infections and therefore prevention messages must still be targeted towards married or other stable couples. It is also part of the appeal of the “concurrency” hypothesis as a dominant mode of HIV transmission.
The stereotypical view of this situation is that African men are ones that introduce HIV into relationships – they are the ones that engage in extra-marital relationships, they are the ones that hire prostitutes, they are polygamous, they have more power in sexual relationships, etc – in short, they are dogs [exaggeration added]. A new study, which includes both a meta-analysis as well as secondary analysis using population based DHS data, sugests that this stereotype may not be justified – that women might be as likely to be the “index case” as men.
Oghenowede Eyawo and co-authors find:
The proportion of HIV-positive women in stable heterosexual serodiscordant relationships was 47% (95% CI 43–52), which shows that women are as likely as men to be the index partner in a discordant couple. DHS data (46%, 41–51) and our sensitivity analysis (47%, 43–52) showed similar findings.
Of course there might be biases that occur outside of relationship formation that might lead to more gender balance in more stable relationship vs. other forms of relationships that we might also care about. But the findings of this study are very interesting from a policy perspective because much HIV programming focuses more on men as index case than women and if this is not true than additional efforts must also be directed at women as well.Share on Facebook
Quick: What is the most common means of committing suicide globally? I must admit the answer to this one surprised me: pesticides. I knew it was big, but I would have never guessed that upwards of a third of all suicides are committed using pesticides that are readily available for agriculture. In Sri Lanka, evidence from a new study that looked to measure the toxicity of readily available pesticides in PLoS Medicine suggest that upwards of half of suicides are committed using these readily available products.
Logic would sugget that restricting the availability of the harmful pesticides might be an effective strategy to reduce suicide. A summary of evidence in an accompanying comment does in fact support this view – that a move by the WHO to ban the availability of some classes of pesticides was associated with lower suicide deaths, most notably it appears that changes in the availability of pesticides is associated with reductions in deaths from suicide but not necessarily attempts at suicide.
Within the public health community, means restriction is viewed as an effective way of reducing mortality from suicide. Since not all attempts at suicide are successful, by restricting access to the most effective means, overall mortality rates can be reduced. Similar arguments have been made with regards to the availability of handguns in the United States.
Of course restricting pesticides might be detrimental to agricultural productivity, so we might want to consider these trade-offs. But experiences in other countries has suggested that restricting the availability of harmful pesticides, either through increased targeting of the product, through the use of less toxic pesticides, or other means can help achieve the public health benefits without decreasing agriculture productivity.
There is far too little research at the intersection of health, agriculture, and the environment. This is one more example of a real tangible problem that could be addressed with a stronger evidence base.
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A study published today in the Lancet brings some exciting news on the polio vaccine front. There has been tremendous progress globally at eradicating polio since a global eradication effort was launched in 1988, but as the polio folks have learned all to well is that progress against this disease is not a linear battle (take note malaria folks). In essentially the first 20 of the eradication effort years, cases of polio were reduced by 99%, however, the last 1% has remained elusive.
Part of the problem stems with the effectiveness of current vaccine formulations. There are three strains of the polio virus that cause significant illness: type 1, type 2, and type 3. One can develop a vaccine against one or more of these strains, however, in general adding another strain means reducing the overall effectiveness of the vaccine against the included strains. Coverage is traded off with effectiveness. Until recently, we had monovalent (meaning one strain) vaccine formulations against each of these strains as well as a trivalent formulation which contained all three.
The trivalent vaccine was the workhorse of the eradication effort – it was what helped get us to where we are today, But because the trivalent vaccine is not perfectly effective there are always enough cases of the diseases to allow it to continue to spread in the population. The solution to date is to switch to the monovalent vaccine, usually for type 1, which is much more effective than the trivalent vaccine. The problem, of course, is that if only the type 1 vaccine is given, people are not protected against the other strains of the virus, leaving them vulnerable.
The type 2 strain of the virus has essentially been eliminated and is therefore no longer a priority. The inclusion of this strain in the vaccine might therefore be interfering more than it is helping. This new study investigated the effectiveness of a bivalent vaccine – against types 1 and 3 and found that it was nearly as effective as the monovalent formulation of either strain and more effective than the trivalent vaccine. In this case two is company but three is a crowd. This is good news – it is believed that this new vaccine could be adopted quickly and could be used in this next phase of the eradication effort.
Polio eradication still faces many important challenges going forward – perhaps most notably the fact that the effort is only funded at the level of about half of what is needed to carry on for the next few years – but this is clearly good news that will move the effort one more step ahead.
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The Institute for Health Metrics and Evaluation, in collaboration with the Harvard School of Public Health, the Lancet, the London School of Hygiene and Tropical Medicine and a few others have issued a call for abstracts for a really interesting upcoming conference in March. In their words:
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The conference will highlight innovative methods, the latest debates in measurement, and the transformation of data into effective policy for improved population health. Sessions will be organized to promote debate, discussion, and an open exchange of ideas.
Malaria is a major public health problem in India, however, the WHO estimates that there are only 15,000 malaria deaths a year in India. Important, but given that we are talking about a population of over a billion people, this is really just a drop in the bucket. The WHO estimates are based on statistics reported from the Indian Government, which are based on facility based reports of deaths.
But using cause-of-death estimates generated from the use of new verbal autopsy methods in the nationally representative Sample Registration System, researchers estimated that it is possible that deaths from malaria could actually range from 125,000 to 277,000 deaths a year – or roughly 10 times higher than the WHO estimates!
Measuring morbidity and mortality from malaria has always been tricky. The main symptom of malaria – fever – is a common symptom of many illnesses, so attributing cause of death when fever is present can be difficult. As well, malaria is actually reasonably easy to treat if prompt treatment is given, but prompt treatment is rarely given if malaria is not diagnosed, so many malaria deaths may be underreported. In addition, many malaria deaths occur in rural areas where many deaths occur outside of facilities are are not always reported.
No method is going to be perfect, and there are likely substantial measurement issues associated with the use of verbal autopsy methods, but given the huge discrepancy between the measures, it does suggest that something else is at play here. If we believe these new estimates, under reporting of malaria deaths in India alone accounts represents 20-25% of the estimated global mortality from malaria. These findings also raise some serious doubts about the WHO’s estimates from other countries. How could the WHO’s estimates be so wrong?Share on Facebook
There is a lot of focus on providing access to health insurance in many global health policy discussions – calls for universal access to health insurance are common. But what does providing access to health insurance actually do? Improving financial access to health services and reducing the likelihood of catastrophic health expenditures are important stated priorities for most health reforms but the actual ability of health insurance reforms to achieve these goals is not well understood.
A new paper by my former classmate Sebastian Bauhoff out this month in Health Economics examines this question investigating the impact of the rollout of health insurance in Georgia, a middle-income country. In Georgia, the government subsidizes the purchase of health insurance for the poor through tax financed vouchers through its Medical Insurance Program for the Poor. Households then use these vouchers to purchase insurance from private insurance companies. Using a regression-discontinuity study design the authors are able to evaluate the impact of the health insurance by comparing outcomes of eligible households to those not eligible for the insurance. The paper is able to look a a wide array of outcomes, which is one of the real strengths of this paper.
They find that the health insurance program:
….reduces out-of-pocket expenditure among program beneficiaries, increases the proportion of care provided at reduced price or for free, and lowers the risk of moderate and catastrophic expenditures
Like many other similar papers of health insurance expansion, the authors find little impact of the program on self-reported health status, health system responsiveness (satisfaction), and the use of preventive health-care services and health-related behaviors. Of course, in the long-run this might change, but it seems that we should not expect short-run effects on many of these indicators.
The impact of every new insurance scheme has to be evaluated locally – no two countries adopt identical health insurance schemes and implementation of the program will also matter, even locally within a given country, all of which will eventually influence the impact of the programs. It is precisely for this reason that we need many rigorous examinations, such as this one, of these experiences. This paper is an important new contribution to this literature.Share on Facebook
You know you are a mainstream global health issue when you get your own report from the World Health Organization – with a forward from Margaret Chan herself! Dare I say that you might also be considered “fashionable”.
Earlier today, the WHO released its first report on the Neglected Tropical Diseases. The eloquent Director General writes the following in her introduction about the NTDs:
Neglected tropical diseases have traditionally ranked low on national and international health agendas. They cause massive but hidden and silent suffering, and frequently kill, but not in numbers comparable to the deaths caused by HIV/AIDS, tuberculosis or malaria. Tied as they are to impoverished tropical settings, they do not spread to distant countries and only rarely affect travellers as, for example, during outbreaks of dengue. Because they are a threat only in impoverished settings they have low visibility in the rest of the world. Though greatly feared in affected populations, they are little known and poorly understood elsewhere. While the scale of the need for prevention and treatment is huge, the poverty of those affected limits their access to interventions and the services needed to deliver them. Diseases linked to poverty likewise offer little incentive to industry to invest in developing new or better products for a market that cannot pay.
I think that is a good summary of the main challenges to the control of the NTDs. To this I would also add that they are major contributors to the global burden of disease mainly via morbidity, which has profound health consequences but also can inhibit the education and productivity of affected individuals.
The fact that this report exists speaks to the great progress that has been made in this area over the past decade. My first official global health job was with the International Trachoma Initiative years ago where I was charged at looking at developing the strategy for an integrated strategy for trachoma with other neglected tropical diseases. Now integrated approaches are being tested around the world, millions of dollars in new funding have been provided by donors, and to this day NTD control remains one of the best examples of successful public-private partnerships.
While the area has received increased attention from many of the past few years, many important challenges remain. Over a billion people are likely infected by these scourges and despite the fact that safe, effective, and low cost treatments and intervention exist to both prevent and treat these conditions, these intervention still are not reaching everyone who needs them.
To celebrate this report, here are some links to some NTD related sites that you might enjoy:
1. The End the Neglect Blog – A whole blog devoted entirely to the NTDs, including the Worm of the Week Feature!
2. Alanna Shaikh’s post on “Why the NTDs annoy me” – very entertaining.
3. The Center for Global Development’s Case Study on Onchocerciasis from the Millions Saved Project.
4. I highly recommend this article (which I think is free) by Adrian Hopkins from the Mectizan Donation Program.
5. This overview of Official Development Assistance for the NTDs by Bernard Liese and Liane Schubert.
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