Global Good (Testing Passive Cooler on Camel)
Global Good (Testing Passive Cooler on Camel)

Understanding Vaccination: The Cold Chain

Global Good (Testing Passive Cooler on Camel)
Global Good (Testing Passive Cooler on Camel)

Delivering vaccines is hard work. One of the hardest—and least-discussed—problems of vaccination is the cold chain, the challenge of keeping a vaccine at cold temperatures all the way from production, through shipping to a given country, through local delivery to a health clinic, and finally delivery into someone's body. As we continue World Immunization Week, let's dig in to this slightly geeky technical problem—one that literally means the difference between life and death.

Why Keep Vaccines Cold?

While some vaccines are stable at a relatively wide range of temperatures (some as hot as 40° C), most vaccines must be kept cold in order to maintain their potency. What's more, some vaccines must be kept in a strictly controlled range of temperatures (typically 2°-8° C) or they go bad. Temperatures too cold or too warm can cause a dose of vaccine to lose its "immunogenicity," or its ability to affect the human immune system.

There's a related problem here: Some vaccines that are able to be exposed to higher temperatures are not labeled as such. This causes workers to refrigerate those vaccines unnecessarily (treating all of them the same), which is a waste of energy.

Why Is This A Challenge?

Almost 50% of health posts providing vaccines have no (or very minimal) access to the power grid. Without grid power, it's hard to have reliable refrigeration (and even if you have grid power, in some parts of the world that means lots of outages—which can be hard on a refrigeration unit).

Transporting cold vaccines to remote areas and then storing them properly in those locations are both serious problems due to the general lack of reliable electricity for cooling. In some parts of the world, we're talking about literally packing a foam cooler with ice and vaccine, then carrying that cooler to a village.

To compound the cold chain's core logistical challenge, we are now able to vaccinate children against more diseases than ever. This is great! But more kinds of vaccines means more vaccine volume to carry around and keep cold. One estimate shows that the volume of vaccine per child has gone from 50cm3 in 1980 to 200cm3 in 2010. That's a fourfold increase in vaccine volume per child, to protect against roughly 2.5 times the number of diseases over the same time period.

Promising Solutions

The best solution to this problem would be the development of vaccines that do not require refrigeration. While work is underway, it may not be possible for certain kinds of vaccines, and even if it becomes possible, that doesn't solve any problems today; the R&D is years out. But, for the record, "thermostable" vaccines are what we hope for down the road—along with better labeling of the ones we have today.

There are also interesting technological solutions in testing. The simplest is a "passive long-term cooler," which you may know better as "a really big, beefy Thermos©-style container." When you make the leap from traditional "tailgate party cooler full of ice" to a precisely engineered vacuum flask, you can extend the cold storage from a matter of hours to an entire month with no power. This is huge, it's cheap, and it's simple. (On the hand, it does require ice...which typically requires refrigeration to create.)

Another approach for health posts without grid power is a Solar Direct Drive. These devices use solar power to drive a compressor, creating ice, then store power in the ice rather than in a battery. This is more resilient to power losses than a traditional refrigerator or battery pack, and a large block of ice can keep the system cool for up to five days even if solar input is low or nonexistent (for instance, on cloudy days).

The final technological solution in the pipeline is Ice-Lined Refrigerators (ILRs). These exist today, but improvements to the basic technology could mean these refrigerators could operate on about 8 hours of grid power per day, and still keep vaccines in the required cool range for several days in the event of a power failure.

Systems Thinking

The cold chain is a logistical problem with many inputs. To improve its performance, we have to think about all sides of the problem: improved vaccines (ideally requiring less refrigeration or less volume); improved refrigeration (requiring less or no power); and improved delivery systems (only deliver the needed amount of a vaccine to a given area "just in time," reducing the need for local storage off the grid). All of these elements are in play.

In a recent pilot program in Nigeria's Lagos State, all these elements were addressed. At the beginning of the trial, half the district health posts had inadequate vaccine stock on hand; at the end, all were properly stocked. After the program, pentavalent vaccination rates had risen by 15% within just one month. (The "penta" vaccine protects against five diseases: diphtheria-tetanus-pertussis (DTP), hepatitis B, and Haemophilius influenzae type B.) Nigeria is just one of three countries (the others being Afghanistian and Pakistan) in which polio is still endemic, so improvements to vaccination there are key to beating polio.

The take-away: by tackling the cold chain problem from multiple angles, we can improve delivery of vaccines, reduce waste, and save both lives and money. That's a goal worth fighting for.

YouTube / thelostdisney
5 Fun Facts About Health, Toilets, Muppets, and Presidents
YouTube / thelostdisney
YouTube / thelostdisney

We've been running a series about global health since August 2013. Here are five of the most interesting facts we've uncovered since then.

1. There is a "World Toilet Organization" Run By "Mr. Toilet"

Jack Sim goes by "Mr. Toilet." He left the business world to found the WTO—no, not that one, the World Toilet Organization—in 2001. Starting that year, Mr. Toilet declared November 19 "World Toilet Day," and since then has been on a mission to bring sanitation to people in developing countries.

I urge you to drop what you're doing and watch this short video about Mr. Toilet. Yes, he says "shit" a lot. And it's awesome.

In addition to founding the World Toilet Organization and establishing World Toilet Day, Mr. Toilet is working to convince the world to abandon flush toilets, because they waste water. Sim reminds us that flush toilets waste up to 22 liters of water every day. Something to think about next time you debate whether to "let it mellow."

Learn more in 5 Reasons World Toilet Day is Awesome.

2. The Seven Dwarfs Helped Fight Malaria

Disney made an animated film in 1943 called The Winged Scourge featuring the Seven Dwarfs. It was the first in a series of animated propaganda shorts dealing with public health issues, and the only to feature established Disney characters. I'll summarize this ten-minute video for you: mosquitoes transmit malaria, malaria is bad, so let's kill mosquitoes. With help from dwarves. (Snow White doesn't make an appearance.)

Note that around 0:45 in the video, we see that malaria is still established in the United States in the world map. Malaria wasn't eliminated in the U.S. until 1951.

Read more in 8 Surprising Facts About Malaria.

3. George Washington Had Tremendous Health Problems

"Life of George Washington—The Christian Death" by Junius Brutus Stearns, courtesy of the Library of Congress

George Washington is likely the founding father to have suffered from the widest variety of awful diseases, so let's review some of the worst things that happened to him. As a young man, Washington traveled to Barbados with his brother Lawrence in 1751, in an attempt to cure Lawrence of his TB with fresh air. The attempted cure failed, and George became infected with TB in the process. He also managed to pick up smallpox while in Barbados.

George Washington returned from Barbados only to come down with pleurisy, while his brother Lawrence died from TB. George also contracted malaria (see above), and later suffered from dysentery. He died at age 67 while being treated for a throat infection. The treatment involved bleeding him (32 ounces of blood removed—probably what actually killed him), making him gargle vinegar, inducing vomiting, and nearly suffocating him with a molasses/butter/vinegar potion.

Washington's struggle with disease was so epic that PBS produced an entire article describing and discussing his medical problems and how they might have been solved today. (They noted that he also suffered from diphtheria, quinsy, a carbuncle, pneumonia, and epiglottitis. Ouch. Oh yeah, and he lost his teeth to infection and decay, leaving him with just one remaining tooth upon inauguration as president. He lost that one too.)

Check our the history of presidential pain in 6 Awful Illnesses Suffered By US Presidents.

4. Cookie Monster Promotes Handwashing and Healthy Eating

In April 2013, Cookie Monster emphasized the importance of handwashing as part of an effort to promote sanitation work around the world. (2.5 billion people don't have access to toilets!) He granted an interview on the subject, conducted by the Impatient Optimists blog. Here's a snippet:

Impatient Optimists: We know you’re a cookie enthusiast. Can you tell us your cookie eating ritual?

Cookie Monster: Me cookie eating reputation precedes me. Of course me have ritual! First me wash hands. This part very important because it help keep me healthy. Me not sure exactly how long me wash, but me sing the ABCs slowly and when me get to Z, it time to rinse and then look out, om nom nom nom nom. Me also like to share me cookies with Elmo and Big Bird. Little known secret, a birdseed cookie is delicious.

Cookie Monster also famously sang in 2005 that "A Cookie is a Sometimes Food" in an effort to combat obesity. (In the song, various fruits are declared "anytime foods.") In this video, he struggles with the choice between fresh fruit and a delicious cookie:

Cookie Monster also tackled food issues with a 90s-style rap about healthy eating, complete with gold chains. "Nutrition, it really hip!" Me love it.

Read more in 13 Sesame Street Muppets That Make a Difference.

5. One Man Created Eight of the Most Common Vaccines

Image courtesy of Images from the History of Medicine

Although most people have never heard of him, Maurice Hilleman developed dozens of vaccines, including eight vaccines that you may have received. Hilleman developed vaccines for chickenpox, Haemophilus influenzae bacteria, hepatitis A, hepatitis B, measles, meningitis, mumps, and pneumonia (among many others). His vaccines saved millions of lives, and I've received a bunch of them myself! His obituary read, in part (emphasis added):

"Hilleman is one of the true giants of science, medicine and public health in the 20th century," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases.

"One can say without hyperbole that Maurice has changed the world," he added.

... "If I had to name a person who has done more for the benefit of human health, with less recognition than anyone else, it would be Maurice Hilleman," Gallo said six years ago. "Maurice should be recognized as the most successful vaccinologist in history."

His obituary is well worth a read, including colorful lines like: "'Montana blood runs very thick,' [Hilleman] said later, 'and chicken blood runs even thicker with me.'" (He grew up on a farm and worked with chickens quite a bit in developing vaccines.) His story is also told in the book Vaccinated: One Man's Quest to Defeat the World's Deadliest Diseases.

Read more in 5 Things You Might Not Know About Vaccines.

YouTube / ONE
How Missed Calls Amplify Farmers' Voices
YouTube / ONE
YouTube / ONE

This week, Farm Radio International (FRI) announced the results of an innovative poll covering thousands of farmers. The biggest surprise was the way farmers voted: by calling a phone number and hanging up.

The survey was conducted in Tanzania, where smallholder farms (small family farms) make up around 75% of all farm production. FRI, an international radio service that partners with local stations, wanted to poll those farmers in order to help make their voices heard by the Tanzanian government. But how do you reach thousands of tiny farms spanning a whole country? In the case of Tanzania, the answer was radio talk shows and basic cell phones.

Photo courtesy of ONE / Do Agric

The Power of Radio Talk Shows and Cell Phones

Across Tanzania, there are radio stations broadcasting talk shows aimed at farmers. Those programs are already popular for the people the survey aimed to reach, so FRI partnered with five radio stations in different regions across the country. The local presenters added discussion segments to their programs dealing with the poll issues.

Radio broadcasters concluded the poll segments by asking yes/no questions, then giving out phone numbers that voters could dial into. But people generally don't want to waste their cell phone minutes on a poll, so a clever solution came into play: just call the number, then hang up. The missed call is logged, and that log constitutes a vote. This system is called "Beep to Vote," and it's free for voters because the missed call doesn't incur charges for using cell phone minutes. For yes/no questions, there was one phone number for "yes" and another for "no." A total of 8,891 smallholder farmers participated.

In addition to the "Beep to Vote" yes/no questions, the poll included a multiple-choice question that most voters responded to using SMS. Voters texted a single character ("1" for the first option, "2" for the second, and so on) to a specified phone number, and those results were tallied by computer. In addition to the SMS voting method, farmers could opt to make a voice call to an automated system, listen to the five options, and press a number to indicate their choice. 4,372 people responded to the multiple-choice question. The system was also able to send SMS reminders to voters in case they voted for one of the poll questions, but not the others.

The data was crunched in realtime using a system made by Telerivet, so poll workers could watch as votes came in. The system also checked incoming phone numbers so each phone (which roughly equates to each voter, or household) could only vote once per question.

Photo courtesy of ONE / Do Agric

Why This Matters

From a technological perspective, this poll is a brilliant example of choosing the right technology for the job. If a similar poll were conducted targeting middle-schoolers in the United States, it's likely that technologies like YouTube videos and click-to-vote within the video would be used. But for these Tanzanian farmers, the prevalent technologies are radio and cell phones. By putting them together, in a near zero-cost way, FRI was able to collect data that could influence government policies, which in turn could change livesusing just cellphones and radio.

This poll was part of a campaign called Do Agric, focused on encouraging African leaders to invest more in agriculture, in order to improve farming (and in turn, daily life) in Africa. Here's a video about the program:

When the results were announced earlier this week, Tanzania's President Kikwete said, "Action on agriculture has to be today, not tomorrow!" The voices of 8,891 farmers reached the president's ears.

For more on the survey, check out FRI's page on methodology and results.


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