Tag Archives: Ebola 2014 West African Outbreak

Has #Ebola Death Toll Surpassed Malaria in West Africa?

In the earlier days of the West African Ebola outbreak, it was not uncommon to hear people note that we should not panic about Ebola because, after all, far more people are killed from Malaria than Ebola. This is of course an irrelevant argument. That is like telling a person who has lost their family in a tragic airplane accident that it isn’t so bad because, after all, far more people die in car crashes than aircraft crashes. For example, on August 5th, James Bell write in the Guardian, in a piece called Concerned about Ebola? Youโ€™re worrying about the wrong disease:

Since the Ebola outbreak began in February, around 300,000 people have died from malaria, while tuberculosis has likely claimed over 600,000 lives. Ebola might have our attention, but itโ€™s not even close to being the biggest problem in Africa right now. Even Lassa fever, which shares many of the terrifying symptoms of Ebola (including bleeding from the eyelids), kills many more than Ebola โ€“ and frequently finds its way to the US.

I’m not picking on James Bell here. A lot of people said things like this, and the facts are true, though as I said, there is almost always (actually, in exactly N-1 scenarios within a given domain of scenarios) an argument that goes like this, and it really isn’t particularly relevant unless one is tasked with dividing up a fixed set of resources that will be used for a fixed set of problems. Resources rarely come that way and problems are rarely solved that way. As I pointed out earlier, consider the thought experiment where you have $10,000,000 that you want to give to either developing an Ebola vaccine, or a Malaria vaccine. Since billions have been spent on developing a Malaria vaccine and there still isn’t one, your donation would be a drop in the bucket. Retrospectively, it would be equivalent to something like the combined costs of couriers and mail by researchers working on a Malaria vaccine over the last few decades. Or the cost of coffee and donuts in the break room. Or conference travel fees. Or something like that. The point is, a bunch of millions of dollars might actually produce an Ebola vaccine given the starting point we have now, or at least, move us a good deal in that direction.

But now, we can ask if Ebola in the countries that are heavily affected right now is still “minor” compared to Malaria.

This is a matter of numbers and the numbers are hard to come by. James Bell notes that between February and July, inclusively, there had been over 300,000 malaria deaths, I assume world wide. So the comparison is not really relevant; we should be looking at what is happening specifically in, for instance, Liberia, Guinea, and Sierra Leone (or the three combined perhaps). Comparing world wide figures to a regional outbreak is a bit like reducing the Malaria death rate by shifting from numbers from countries that have endemic Malaria to include the global population.

It is hard to know how many people die of malaria every year, and the quality of the data varies considerably from country to country. A fairly recent study (here’s a discussion of it) suggests that an older estimate of 600,000 deaths per year should be doubles to 1,200,000 deaths per years. Having worked and lived in a region with some of the worst malaria (measured numerous ways) for several years, I can easily accept a doubling of numbers. If we assume that 1.2 million is right, by the way, Bell’s number of 300,000 is actually conservative.

Using data from that malaria study and WHO’s Ebola data, we can make some comparisons. I’m including all the information so you can check my work.

Here we have data from Liberia, Guinea, and Sierra Leone. The population number and malaria deaths per year are both from the aforementioned study and pertain to 2012. Then I divided malaria deaths per year by 12 to get a monthly value. I’m more comfortable working in months than years because an Ebola outbreak is normally short lived, and the number of deaths changes dramatically from month to month.

Following this we have the total number of Ebola deaths per country (summed in the right hand column as are the above mentioned data) and the approximate number of months of the outbreak. Then, the total deaths divided by the number of months. This constitutes a low-ball estimate of deaths per month from Ebola for the given expanding outbreak. Here we can see that in the comparison between Malaria and Ebola, it is not clear that one is a greater threat than the other (142:92, 49:67, 145:144).

Then we have the August-only monthly number of deaths. Here we dee that Ebola is huge compared to Malaria. So, back when people were saying “Malaria is worse,” in late July and early August, Ebola was starting to prove them wrong.

The last two numbers are calculated for all three countries combined. Here we are going out on a limb, and it is better statistically to crawl out on a thicker limb than a thinner limb. I made some estimates here, and those numbers conform to what is being talked about by WHO and others. If Ebola continues to spread at its current rate the daily number of new cases could be between 150 and 300 by the beginning of January. I state these as low vs high estimates, but actually, they are both conservative. Multiplying this by 30 days in a month, and dividing by 2 to approximate the ca 50% mortality rate, we have conservative numbers for Ebola that leave Malaria in the dust. Even if the doubling of estimated Malaria death rates should be doubled again, Ebola will be a bigger factor than Malaria.

Liberia Guinea Sierra Leone Total
Population 3,954,977 10,068,721 5,696,471 19,720,169
Malaria Deaths Per Year 1706 586 1734 4,026
Malaria Deaths Per Month 142 49 145 336
Ebola Deaths Total 508 400 461 1,369
Months of outbreak 6 6 3
Monthly average Ebola deaths 92 67 144 303
August Ebola Deaths 644 148 224 1,016
Estimated Janurary Ebola Deaths (low) 4,500
Estimated Janurary Ebola Deaths (high) 9,000

So that is why we should stop saying that Ebola is not Malaria, so relax about Ebola.

More on Ebola:

Update on West Africa's #Ebola Outbreak: Getting worse

The news is bleak. I don’t have a lot of confidence in the reported numbers. At one time it was said that on a nice Saturday in the summer, four out of five cars driving around in downtown Boston were looking for a parking place. This is somewhat like the situation in Liberia and possibly other affected areas. There may be as many Ebola victims driving around in taxis looking for a clinic as there are in clinics. Or maybe a fewer. Or, maybe more. Maybe a lot more.

But, we have to work with the data we have. There are two charts based on the information provided by WHO for up through September 6th. I’ve projected each data set out 90 days. Since there is no abatement in frequency of new cases, and in fact the number continues to increase on average, and since WHO is claiming that the situation in the worst hit areas is pretty much out of control, a 90 day projection seems reasonable. In other words, there is no reason to think that the relative rate of new infections is going to change because of any outside intervention or internal change in the situation.

The first chart shows the number of new cases. This varies a great deal from report to report. Some of that variation over time is probably real, reflecting the internal complexities of disease spread. But I suspect it is mostly administrative. If a bunch of cases don’t get into one report, the get into the next report. This explains a nearly perfect alternation between increase and decrease between successive reports.

Screen Shot 2014-09-10 at 1.03.44 PM
The second chart shows the number of cases over time, accumulated. This Projected outwards, we can guess that by around the beginning of 2015, there will have been over 10,000 people who have been infected by Ebola in West Africa (including Nigeria and Senegal as well as the main area of the outbreak), and over 5,000 deaths. Since I know you are curious, if this is projected out over a year or so, the number of infected people goes to between 60,000 and 70,000. I have no idea if this is realistic.

Screen Shot 2014-09-10 at 1.02.24 PM

The situation is bad and getting worse.

#Ebola in West Africa: Update

WHO has put out very few updates in the last several days. The most current update is August 28th, and it pertains to information from August 26th and before. Based on that update, the total number of cases (confirmed, suspected, etc.) is ow 3069 with 1552 deaths. The number of new cases per day may be increasing, may be decreasing; hard to say at this point. Here’s the new cases per day since the second week of July:

Screen Shot 2014-09-02 at 11.08.33 AM

Senegal now has one case, a person who traveled there from Guinea. He had contact with a lot of people including health workers and family before it was figured he may have Ebola. There is no word from the Congo since I last wrote about it, at least from WHO.

I’m sure Murphy’s Law will apply and WHO will issue new information soon after this post goes up, so expect an update very soon.