It's been a long time coming, and indeed we are still not there yet, but it is becoming increasingly clear that we really do have the first effective vaccine against a parasitic disease in humans. . . It is not usual practice to publish the results of trials in pieces, and there does not seem to be a clear scientific reason why this trial has been reported with less than half the efficacy results available.It appears that the NEJM timed released to coincide with a major meeting of the Gates Foundation on malaria. The hyping of research results cannot be considered good practice. In the study itself concerns are expressed about side effects, such as an apparent increase in meningitis and seizures.
With these cautions in mind, the implications are potentially huge -- most significantly for improving the lives of Africans who live under the burden of the disease. Here is what I wrote in 2008:
Why does malaria matter? According to Jeffrey Sachs:Clearly, a successful malaria vaccine, even at 50% effectiveness, would have profound and far-reaching consequences for Africa and the broader world.
The numbers are staggering: there are 300 to 500 million clinical cases every year, and between one and three million deaths, mostly of children, are attributable to this disease. Every 40 seconds a child dies of malaria, resulting in a daily loss of more than 2,000 young lives worldwide. These estimates render malaria the pre-eminent tropical parasitic disease and one of the top three killers among communicable diseases.The Economist reported a few weeks ago on efforts to eradicate malaria. The article referenced a study by McKinsey and Co. on the “business case” (PDF) for eradicating malaria. Here are the reported 5-year benefits:
• Save 3.5 million lives
• Prevent 672 million malaria cases
• Free up 427,000 hospital beds in sub-Saharan Africa
• Generate more than $80 billion in increased GDP for Africa
For example, successful deployment of a vaccine would have large implications for analysts whose work depends upon making assumptions about the future. Consider that the assumptions used to project future emissions of greenhouse gases from Africa generally do not factor in the GDP boosting-potential of malaria vaccines (in the sense that GDP growth is assumed to be at recent levels or lower). Again from my posting on this topic back in 2008:
In case you are curious the IPCC SRES assumes future GDP growth rates in Africa (combined with Latin America) of 3.8% to 5.5% per year to 2050.So what are the implications of eradicating malaria for future greenhouse gas emissions from Africa?
To answer this question I obtained data on African greenhouse gas emissions from CDIAC, and I subtracted out South Africa, which accounts for a large share of current African emissions. I found that the average annual increase from 1990-2004 was 5.2%, which I will use as a baseline for projecting business-as-usual emissions growth into the future.
The next question is what effect the eradication of malaria might have on African GDP. The McKinsey & Co. report referenced a paper by Gallup and Sachs (2001, link) which speculates (and I think that is a fair characterization) that complete eradication could boost GDP growth by as much as 3% per year. This would take African emissions growth rates to 8.2%, which is still well short of what has been observed in China this decade, and thus not at all unreasonable. So I’ll use this as an upper bound (not as a prediction, to be clear). So if we graph future emissions under my definition of business-as-usual and also the Gallup/Sachs upper bound, we get the following curves to 2050.
The figure shows that by eradicating malaria, it is conceivable that there will be an corresponding increase in annual African emissions of more than 11 GtC above BAU. . .
The implications should be obvious: If a goal of climate policy is simply to “reduce emissions” then this goal clearly conflicts with efforts to eradicate malaria, which will inevitably lead to an increase in emissions. But if the goal is to modernize the global energy system — including the developing the capacity to provide vast quantities of carbon-free energy, then there is no conflict here.
The consequences of the eradication of malaria should be received as great news, but such a discovery has the potential to send scenario authors back to the drawing board as it could add to existing scenarios as much as 5 Chinas (! in 2011) worth of emissions in 2050. Even viewing this idealized value as an upper bound, the lesson here is that emissions scenarios have disproportionately large errors on the high side (PDF). There are no doubt a wide range of similar types of assumptions and scenarios about Africa that will require rethinking (e.g., food production, uurbanization, conflict, etc.).
Eradication of malaria would be a monumental accomplishment with profound consequences for Africa and the world, beyond the obvious benefits to human health. It is not too early to begin to think through what those might be.
20 comments:
First, let's celebrate.
Second, the relationship between malaria and economic growth is a good bit more complicated than suggested by Gallup and Sachs. I would expect a drop in fertility and an increase in education in Africa as a result of this breakthrough.
Third, the relationship between economic growth and emissions is not that simple either. Fewer and better educated people means lower emissions. This would partly offset the higher emissions due to the increase in per capita income.
-1-Richard Tol
Thanks, indeed let's celebrate ;-)
But also lets admit that prediction is a mugs game. I am not willing to bet on African GDP scenarios. I'd rather adopt policies robust to a wide range of such scenarios -- and that means being prepared for the possibility (not certainty) of future rates of African GDP growth comparable to that seen in India and China over the recent decade.
-2- Roger
If the Africans get their act together on universal education, growth could be very rapid.
In fact, catch-up rates have accelerated over time. China grows faster than South Korea did, and South Korea was faster than Japan, and Japan was faster than Germany and France. Extrapolation suggests that Africa would set need speed records.
The one bright spot is that solar energy is plentiful in Africa. If the cost of solar power systems continues to decrease, they might actually have a chance to produce energy without fossil fuels there.
-3- myself
new speed records, even
Roger -
How do you controlled for the potential negative impact resulting from potential increases in Africa's population in your future GDP projections?
What I find particularly interesting about the projections of what may happen with vaccine development is that they aren't accompanied with projections regarding spending (relatively less?) money on other proven ways to reduce malaria - such as mosquito nets, or improved housing which would have ancillary benefits.
-6-Joshua
Not sure I understand your question, can you rephrase?
Funny how malaria was eradicated from the United States - no need of a vaccine - when white people were the victims, but a vaccine is needed for Africa. In the meanwhile, Africans die.
@Richard Tol
"Fewer and better educated people means lower emissions."
??? Africans today are walking five miles for a bucket of water and cook dinner over cow poop. Fewer and better educated people will mean they drive to work in cars and cook on gas ranges. How does that result in lower emissions?
Sure -
You say the "GDP-boosting potential of malaria vaccines." That seems to be saying that there is a direct relationship between vaccines (the lives they save) and GDP growth.
As I understand it, you are projecting GDP growth as a direct function of population growth (resultant from the use of vaccines).
Are there confounding variables uncontrolled for there? For example, possibly, that increased population growth will run a risk of increasing food instability, cause housing shortages that would cause more spending in areas that bring a lower return in GDP growth than other areas, etc.?
How do you control for the potential that the ratio of GDP growth to population growth would not change at a rate that is consistent with past patterns? I think that my question is somewhat similar to Richard's comment above: the relationship between GDP growth and population growth must be very complex.
If there is any lesson of the first half-decade of the postcolonial era, it is that simply making available a cheap, effective preventative measure will not in itself be effective in reducing the incidence of a disease. Africa's primary problem is African governments, not Trypanosoma.
And lest I be accused of callousness, my father had chronic malaria, a consequence of the years he spent with UNIDO in Africa. Prophylaxis only goes so far.
Funny how malaria was eradicated from the United States - no need of a vaccine - when white people were the victims, but a vaccine is needed for Africa. In the meanwhile, Africans die.
The TVA eradicated malaria in the US by massive application of DDT, combined with the draining of swamps that was done primarily for agricultural purposes. Then we got all enlightened and forced through an international ban on DDT, though, to be fair, the vectors were starting to become resistant also.
"The TVA eradicated malaria in the US by massive application of DDT, ..."
From what I've read, the use of DDT was a very minor factor in how the U.S. eradicated malaria. Do you have a link to support the use of DDT as a significant factor?
Please check your facts re: the "international ban" on DDT. DDT was banned in some places for agricultural purposes because it was overused frequently with the problem of resistance developing as you mentioned. (That said, there was international pressure applied to countries that continued to use DDT). The proper use of DDT for vector control requires a kind of judicious and careful application that is unlikely to take place in poor countries without the infrastructure to pull it off.
There is a lot of misinformation out there about DDT - as a part of a political battle regarding environmentalism. It is a complex issue.
-8- Mark B
It always pays to read the next sentence: Fewer and better educated people means lower emissions. This would partly offset the higher emissions due to the increase in per capita income.
That there could be a possible reduction of malarial infection in sub-Saharan Africa is a welcome development. Unfortunately the possibility must, for the foreseeable future, remain just that, a possibility.
Malaria is just one of a large array of diseases and infections endemic and epidemic in the region, all of which contribute to the average life span of a Zambian male being just under 37 years. There is bilharzia, trypanosomiasis, river blindness, dengue haemorrhagic fever, Leishmaniasis, HIV, hepatitis and even nasties like the putsi fly which all serve to undermine the health of the local people.
A nation-wide vaccination program to combat malaria is something which is far beyond the capabilities of any Health Department in sub-Saharan Africa wherein corruption and inefficiency are as prevalent as the diseases in the country. In Zambia the Government health budget allocates well under $10USD per person per year. The cost of such a vaccination program would have to be subsidised 100%.
Just the logistics of mounting such a vaccination campaign would stretch beyond breaking point the abilities of just about any sub-Saharan African country. Vehicular transportation will be stolen or abused and misused to the point where it ceases to exist. Any aircraft used will be 'officially' hijacked by local politicians in order to demonstrate to the people their power and influence. Central Government will not interfere with any of this so as not alienate their supporters.
I'm afraid that ground-based practicalities make a mockery of any projected increase in sub-Saharan development. No amount of overseas aid can assist, as has been demonstrated by the singular failure of any such aid over the last 40 years or so.
I grew up in Zambia, I went to school there, I worked there and my Mother (90 years old this week) still lives there. I know whereof I speak.
As I wrote, the draining of swamps was an important factor in reducing malaria in the US. However, the final eradication was attributed to DDT.
http://www.malaria.com/overview/malaria-history
The National Malaria Eradication Program, a cooperative undertaking by state and local health agencies of 13 Southeastern states and the CDC, originally proposed by Louis Laval Williams, commenced operations on July 1, 1947. By the end of 1949, over 4,650,000 housespray applications had been made. In 1947, 15,000 malaria cases were reported. By 1950, only 2,000 cases were reported. By 1951, malaria was considered eradicated from the United States.
It is meaningless to ban DDT for agricultural purposes. Most countries still affected by malaria do not have the infrastructure to police use of DDT. DDT ostensibly manufactured for public health can easily be diverted, and it is.
13 Richard Tol
There won't be 'fewer people.' There will be a slower rate of increase. And with or without that 'partly offset,' you'll get a dramatic increase in emissions. Given the concerns of the day, a dramatic increase is a dramatic increase. When people go from burning sticks to burning diesel, it matters very little whether you cut the rate of population increase by 10%.
Once again - what I was asking you was about the relative importance of using DDT relative to other factors WRT eradicating malaria in the U.S.
DDT was banned for use for agricultural purposes in the U.S. So such a ban in the U.S. was not meaningless.
It was not banned for agricultural purposes in many other countries, some of which where it was still widely used and which still saw increases in malaria.
There was no "international ban."
The overuse for agricultural purposes resulted in resistance. When you evaluate in the wisdom or lack thereof of using DDT, you need to factor in the potential loss of life from increased resistance had uncontrolled use of DDT continued - and as you say, in many of the relevant countries, systematic use - of the type needed for DDT usage to be effective - would have been impossible without massive funding.
That same (theoretical) funding could have just as easily been applied to other methodologies - arguably to a more beneficial effect.
You are simply wrong, Joshua. The Stockholm convention, which has 173 signatories, bans DDT for agricultural purposes. If this is not an international ban, then international bans do not exist, period.
I quite clearly said that "Most countries still affected by malaria do not have the infrastructure to police use of DDT". That would not include the US, which is essentially unaffected by malaria.
Gerard -
You're right - DDT was banned for agricultural uses in the U.S. - and not for vector control. And it was banned internationally for agricultural purposes on some countries. I should have said there was no international ban for vector control, and there was not even an international ban for all countries for agricultural uses.
DDT has continued to be used internationally for both purposes.
So what is your point?
So how about some evaluation of the relative importance (compared to other measures) of the use of DDT in irradiating malaria in the U.S.?
Gerard -
I thought you might find this interesting:
"Malaria had been largely eliminated in the U.S. by the time the Centers for Disease Control (CDC) first used DDT in spray campaigns in 1947. CDC's four-year spray effort was designed to prevent the reintroduction of malaria from troops coming home from World War II. Almost twenty years earlier, in 1928, the Public Health Service had already noted the decline of malaria in the U.S. The pockets that persisted in the South until the late 1930s were controlled by the Tennessee Valley Authority's efforts to cut down on mosquito breeding sites by draining swamps and protect the population by building well-screened houses. According to one journalist investigating the issue, "About the best one CDC physician involved in the campaign could say about it was that 'we kicked a dying dog.'"
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