There is little doubt that global efforts to increase vaccination coverage levels among children in developing countries have been effective at increasing the number of children receiving vaccines as well as the number of children who get sick from these preventable diseases. The most recent and perhaps most dramatic example of such success comes from recent efforts to immunize children against measles in Africa. Measles deaths in Africa decreased by about 90% from 2000-2006 following widespread immunization from the vaccines. Widespread adoption of the measles vaccine is perhaps one of the most notable, and I would argue, most under appreciated successes of global health during the past decade.
However, the experiences of other immunization campaigns are not always as dramatic or as positive as the measles story. More often than not we hear about how immunization coverage rates regularly stagnate at levels below those considered optimal for population-level goals, coverage rates wane in some countries, and child mortality declines have not been as large as we would have hoped. Vaccine preventable diseases remain major killers of children throughout Africa, despite many decades of efforts to immunize children against these diseases.
Two recent research papers published in the Lancet have made me aware of two important challenges to immunization programs that I have not given much thought to in the past. In my own research, I have likely glossed over some of the complexities of immunization programs in an effort to analyze complex situations in a simple way (this is, after all, what economists do).
In the first paper, Andrew Clark and Colin Sanderson discuss how traditional measures of immunization coverage do not adequately measure an important aspect of immunization: timing. Aggregating data from dozens of Demographic and Health surveys, they analyze the timing of immunizations relative to the recommended timing for such vaccines and find significant delays in coverage, in most cases a few weeks for each vaccine, but climbing to a few months for the vaccines requiring multiple dosages. In the lowest performing countries, the delays could be very extreme. They have two main findings, such timing may affect the overall effectiveness of immunization programs, but also suggests problems with the current measures used to calculate coverage levels.
In the second paper, Sara Lowther and co-authors conducted a follow-up survey of children in Lusaka, Zambia three years following a major immunization drive to measure effective coverage of the vaccines (measured in terms of having antibodies against measles). They find that only about 70% of children have these antibodies three years after the campaign, which is explained partly due to the fact that a substantial children never received the vaccine, and that immunization naturally wanes over time. As such, coverage levels were sub-optimal.
Both of these papers highlight important challenges in translating what we know works, in theory, to reality. We need better measures to help assess the timeliness of such programs and better ways to measure the impact of these efforts over time.Share on Facebook
For most of the day yesterday, I attended a seminar at Harvard University to learn more about how to use the Africa Map tool. The resource is free and relatively easy to use. The tool will only get better and better as more and more people use it and contribute their own project level data to the project. The technology platform makes such sharing and storing of information easier.
Over lunch, some of the participants and I were talking about how new sources of information could be used to address global health issues. One of the participants was a woman from the Red Cross who was interested in learning how her organization could better use GIS and other information in their projects. We also talked about recent research from Google and Yahoo that has shown that search engine data can be used to predict future flu outbreaks. Pretty neat, except I just read an alternative analysis this morning on a new statistically oriented blog which claims that search engine data is a no better predictor of flu outbreak than just using past information more effectively. We talked about how Facebook and Twitter updates could be used similarly (as I was reading my iPhone for updates on Lance Armstrong’s surgery in Texas – in real time).
Just the same it makes you think. Some of it might may seem like hype for now, but I certainly can imagine a scenario where more and more real time and geographic information gets used in global public health efforts. However, given the very poor state of information on global health issues today (e.g. our the controversies surrounding the measurement of the prevalence of HIV or estimating malaria deaths) it seems a long way off.Share on Facebook
(Photo from MSF website)
Today – March 24 – is World Tuberculosis Day 2009. In respect for this global killer, I thought I would try to summarize what I think some of the key challenges are to an effective global response against this disease:
1. Epidemiology: Approximately one third of the World is infected by TB (1 in 3 people!), although only a small fraction of those with TB infection will ever develop active TB, which may occur any time after infection, sometimes many years later. New cases today are a function of exposure patterns that happened many years in the past. Among other things, this epidemiological profile means that TB will be hard to isolate, that it will require a screening strategy that will need to test a lot of people but may only be able to isolate a few cases, that controlling the movement of TB patients is difficult, and that actions taken today may actually not have impact until much further into the future.
2. Diagnosis: Current methods for screening patients with TB are sub-optimal. Sputum based methods are best suited for population based screening, but miss many cases. Culture and X-ray methods are better tests but are not affordable for widespread use. As a result, TB diagnosis remains a major challenge.
3. Treatment: TB treatment requires treatment over long periods of time therefore adherence and follow up are important to effectively treat this disease, but as most public health people know, long treatment courses are a recipe for disaster. No matter the disease, people in general are terrible patients, and despite the obvious private benefits, the treatment of chronic diseases will always be challenging. That just reminded me, I forgot to take my malaria pill again last night.
4. Drug-resistant strains: Sub-optimal treatment of disease, which despite our best efforts is occurring, is leading to higher levels of resistance among strains of TB. So efforts to scale up treatment more broadly are facing new challenges from increased drug resistance. There are only a limited number of effective drugs against TB and therefore it is really important to ensure that these drugs remain effective.
5. Co-infection with HIV: HIV infection weakens the immune system of patients meaning that infected patients are more likely to develop active disease and more likely to develop more severe forms of the disease. TB infection can also have a negative feedback on HIV disease progression.
To read more about TB, check out:
The Stop TB website.
MSF has also launched a new report today on TB.
Paul Chinnock discuses TB here.Share on Facebook
Breakfast at my delightful 20$-a night guesthouse in Accra is the same every day: two slices of white bread, margarine, a spoonful of marmalade, and two packs of Ivoirian instant Nescafe coffee. Normally I eat alone, however, for the past two days I have been joined by Paul, a Methodist Pastor from Sierra Leone. Paul, a slight and wiry soft-spoken man, is a medical tourist here in Ghana.
A few years back, while lifting a heavy object, Paul injured his back leaving him with chronic pain in his neck and back. Over the years Paul visited a series of doctors in his home country, even paying for an expensive x-ray at a private clinic, but Paul was not able to find a physician able to diagnose and treat his condition. Nothing seemed to work.
Well off enough to afford some options, but not rich enough to go to Europe, through his network of colleagues here in Ghana and clearly at great financial expense to himself, Paul flew from Sierra Leone to Ghana last week to seek care from neurological specialists at the Korle-Bu Hospital here in Accra, hoping for a cure. Every day he goes in for a series of tests, building up to the visit with the neurologist this Thursday. His finances are stretched so thin that he hopes to be able to return as early as Friday, otherwise he is here for a least a few more days due to the flight schedules.
He has no idea how much he will eventually have to pay for his diagnosis and treatment here, so far he has only had to pay out of pocket for a cat scan, which cost him about $300 USD. The medical fees, additional diagnostic tests, flights, and accommodation will cost him many multiples of that figure.
I greatly admire Paul for taking it upon himself to make these arrangements and for having such faith in the ability of modern medicine to help him out. Although I am worried that he will be disappointed. It is not even clear that if he receives a diagnosis this week that he will even be able to benefit from treatment.
But his story struck me on many levels. It is hard to imagine Ghana being a hotspot for medical tourism, but I guess everything is relative. I think it also speaks to an emerging literature in development economics and health that suggests that even people in very poor settings can be very savy health care consumers and are willing to pay more for what they perceive to be quality. I wish I knew more about how prevalent this practice is in Africa.Share on Facebook
1. Cadbury has recently announced that it plans to seek Fairtrade certification for the chocolate it uses in its popular Dairy Milk chocolate bar. This certification will require Cadbury to pay a decent living wage to cocoa producers in Ghana, where the cocoa for this bar will be sourced. Please sir, I want some more.
2. A hot debate right now in Ghana relates to a campaign promise made by the NDC during the last election campaign (in which they defeated the incumbent NPP party). National Health Insurance was introduced in Ghana during the last few years. By the end of 2008, according to government figures, nearly 61% of the population is reportedly now covered by this scheme. Every year, Ghanaians need to renew their insurance card by repaying their annual premium, which ranges from about 7 cedis to up to 48 cedis a year (1.3 cedis=1 USD). The NDC promised that instead of paying annually, Ghanaians will now only have to pay once to buy into the scheme and then (presumably) be insured for life. Lots of people have their doubts about the feasibility of such a scheme, but with premiums representing far less than the majority of funds into the system (I heard 20%, but who knows) and with oil production coming online, I guess it could be feasible. But is this still insurance?
3. An interesting article about how the economic crisis may or may not affect Ghana. A story of a local company who has manage to offset losses in its export markets by targeting the local, bulging middle class. The middle class is adopting a more Western diet and seem willing to pay more for “health conscious drinks”. According to the owners of the fruit juice company, their product will “reduce on the diseases that could come to bear as a result of taking other drinks”. Maybe not, but good news anyway.Share on Facebook
Today is the final day of the inaugural African Health Economics Conference, which was held this week in Accra, Ghana. The conference was well organized, well attended, and provided a lot of interesting discussion both about research findings but also about the role of health economists in influencing health policy in Africa. Health economists from nearly every country in Africa were in attendance.
Among the papers presented, one of my favorites was a paper presented by Evelyn Amsah on behalf of her research team that reported on a randomized evaluation of the effect of the new National Health Insurance in Ghana on the utilization of services. There were a few things I really liked about this study: the creative use of field research methods, the intelligent research design, as well as the main substantive findings of the paper.
In many research projects randomization is carried out by drawing up a list of names, or households, or villages, and then using a computer is used to randomly assign treatment to the relevant units. However, the researchers felt that in their study population such methods were generally not well received as people did not believe that it was actually the computer that was selecting randomly but rather it was a person who was actually selecting among people. So instead, the communities to be treated were brought together in town hall meetings and pieces of paper were placed in barrels and then heads of households came forward and selected a piece of paper. About half of the participants were assigned to treatment, which was to receive health insurance coverage for the entire household, with the understanding of the participants that the rest of the population would receive the treatment in the following year. This method allowed for more trust and acceptance of the trial among the communities. It also provided a fair way to allow for randomization at the household level, rather than the village level.
They also asked the households to keep track of health care episodes and treatment outcomes using really interesting visual diaries. Pictures of children with fevers and other conditions were drawn. Households were asked to tick off a box following each occurrence of ones of these events.
A year after the intervention, the researchers found that there were no differences in the reported number of fevers among the treatment and intervention groups, which was a good sign that their randomization worked. The treatment households reported much higher utilization of formal and less informal care, as we would expect, however this effect was ONLY observed among households living within 5 km of a health facility. It seems that the new Health Insurance is only effective when you have good physical access to health services. This finding is very relevant in terms of thinking about how effective this major policy will be in this country.
Hopefully the full findings of this study will soon be published for all to learn from.Share on Facebook
There is a wonderful overview of the history and current outbreaks of Cholera in Africa in this week’s NEJM by Eric Mintz and Richard Guerrant. They write:
“…[Cholera] is the bellwether of many less dramatic but equally fatal or disabling diseases that flourish in filth and a litmus test of our willingness to tolerate flagrant violations of the human right to clean water and sanitation.”
Click here to read the full free text version of the article.Share on Facebook
Share on Facebook
My bags are almost packed – well almost – because I will be flying to Ghana tomorrow to attend the first ever conference of the African Health Economics and Policy Association. Then I still around for a another week or so to keep working on a few of the projects I am currently working on in Ghana. Let me know if any of you readers are also planning to attend this conference. My apologies in advance if my postings the next few weeks are a little slower than usual, but hopefully there will even be some good papers at the conference worth discussing.
A few days ago, Alana had a posting about the relationship between antenatal care and maternal mortality on her Global Health Change.org blog. Her post, my comments, and a question from another reader got me thinking about about what do we know about the relationship between antenatal care and maternal mortality. I am actually doing some work right now on the effectiveness of the Safe Motherhood set of strategies in developing countries, and although I am most interested in the role of skilled delivery with my own work, I have read a bit about the role of antenatal care as well. I was going to post this as a comment on Alana’s blog, but figured my comments would be too extensive and would likely warrant its own posting. So while I am not an expert on these things, here is my take.
Antenatal care is one of the four pillars of the Safe Motherhood strategy developed over the past 20 years and implemented in most developing countries to reduce maternal mortality. However, just because something is advocated by the WHO and most international health agencies does not mean that it has ever been properly evaluated or even if we know if it works. Sad to say. Much of what we recommend to improve global health has never been subjected to rigorous evaluation. The evidence around antenatal care is believed to be effective based on what I will call “intuitive evidence”. It makes a lot of sense that it would work – who can object to making sure women visit the doctor before giving the birth? – so we advocate for it. But there is little good evidence that is suggests that it does all that much to reduce maternal mortality (there could be lots of other benefits from antenatal care, many of which we likely care a great deal about, but I will set these aside for the moment).
Although in general it is actually hard to say anything about maternal mortality, because it is perhaps the major health indicator that is among the hardest to measure, what we do know is that maternal mortality dropped relatively quickly from about the mid 1880s to mid 1990s in most developed countries, and more recently in some of the middle income countries in the world (e.g. Thailand, Malaysia). These drops happened around the same time as a number of other very important changes, so it is hard to isolate the main driver of these declines. The other trends include declines in fertility rates, declines in infectious diseases, increases in access to midwives and maternity services, increases in access to emergency obstetric care, increases in institutional deliveries, the development of new medicines, such as antibiotics and oxytocic medicines, increases in maternal eduction, and of course increases in access to antenatal coverage. They all could have contributed in some way, but today maternal mortality rates are generally a few order of magnitudes (about 100 times) higher in developing countries than in developed countries. Perhaps the greatest injustice in global health.
In 1932, an article was published in the Lancet that observed that although there had been significant attention given to antenatal care to reduce maternal mortality in the UK, there had been no measured decline in mortality. In fact, one of the conclusions of the author was that it may have even increased mortality due to increased rates of unnecessary caesarean sections and early induced labors. A survey of antenatal guidelines across European countries has shown that there is a great deal of variation between the prescribed number of visits, without any observed variation in mortality rates. To my knowledge, there have not been good studies that have been able to isolate the individual contribution of antenatal on maternal mortality directly, but it seems unlikely that antenatal coverage was the main driver of declines in maternal mortality seen in developing countries.
The bulk of maternal mortaltiy is concentrated during the labor, delivery, and immediate postpartum periods (basically 2-3 days around the birth event) so interventions focused on this time period are believed to play a bigger role in reducing maternal mortality (although even this is not well established). One of the goals of antenatal care is to screen and identify patients who are at high risk of having complications, and it seems that its ability to do this is not very good. There are few good predictors, other than previous complications, that predict future complications (and if you had complications before, then you don’t need antenatal care to tell you that you are at high risk for future complications).
So while there is little evidence to either support or refute the role of antenatal care in reducing maternal mortality, it seems unlikely that it does. Does that mean that we should not focus on providing antental care in developing countries? Of course not. There may be lots of good reasons for providing these services, such as providing education and other services. Does it mean that if we get high coverage of antenatal services we should wipe our hands thinking we have solved maternal mortality. Absolutely not. Many countries in sub-Saharan Africa actually have quite high levels of antenatal coverage and persistently high levels of maternal mortality. Antenatal services supposedly take up large portions of the reproductive health budgets in many countries, leaving less available for other types of reproductive health services. Should countries spend more of these resources on other types of reproductiv health services? Maybe. Should donors provide more money for reproductive health, in particular non-antenatal reproductive health services? Maybe. How would I spend an additional dollar to reduce maternal mortality? I don’t know. These are all questions that warrant more attention from researchers before they can conclusively be answered, but I am willing to bet it is not antenatal care that will be the final answer.Share on Facebook