It was really amazing to see the cold chain in action while in Sudan a few weeks ago. It is even more amazing when you realize all the effort that goes in to making it successful. When Dr. Barbara Connor and Don Cross of the John Dau Sudan Foundation returned from their trip, I asked them about the process and to give some details on how the cold chain for the Duk Lost Boys Clinic was designed and implemented:
On our first visit to Duk Payuel, Dr. Reed and I realized that vaccinations are a crucial need in that area, for basic protection against preventable diseases that kill patients. Thus, the cold chain became a priority in our goals for the clinic. We were fortunate enough to receive a donation through John Dau's hard work, from the Sleeping Ladies that allowed the cold chain to become a reality.
Ultimately we are looking to the Government of South Sudan (GoSS) or other NGO's such as UNICEF to supply the vaccines to the clinic free of charge, but for establishing the feasibility of the cold chain we needed to prove that the vaccines could be kept at the proper temperature throughout the entire time of their transit to the clinic. Vaccines are very temperature sensitive, and the temperature at which they are kept cannot vary outside the range of 2 to 8 degrees Celsius, or the vaccines become inactivated, and are not effective. This is monitored very carefully in the US in pharmacies and doctor's office, and in New York state at least, the state government audits organizations handling vaccines to ensure compliance with those storage and transport requirements for vaccines. The US pharmacist at my hospital records the temperature of the refrigerator that stores only vaccines, twice a day, and the state checks those records. We are expecting our clinic to meet all US standards for the practice of medicine, so we will be following those procedures for vaccines as well.
So we set out to figure out how to bring vaccines to the clinic and keep them the proper temperature from Skaneateles NY to Duk Payuel, throughout two days of flying. It was complicated by the fact that any cold packs that we would use are considered "gels", so they could not be hand carried through security. I had to check a bag in Syracuse, and have it stay cold until Nairobi, and then in Nairobi check on it again, and make sure that it could stay cold all the way to Duk Payuel the next day, even on the Duk Payuel airstrip that has no shade and temps are in the 100's in the shade. That' s why I'm so happy in the video. We did it!!
Don Cross was able to find special thermometers that recorded high and low temperatures, inside and outside of the container, and they were very useful,and are the thermomters that we will use to monitor the temperatures. I had also purchased an inexpensive refrigerator thermomter from Lowe's as a back up, but it only told me the current temp inside the cooler.
So we ordered fifty tetanus vaccines that could be given to pregnant women and children older than the age of 7, from my hospital, at wholesale price. With careful packing of a cooler within a cooler, that was then placed inside a silver insulated envelope used to keep pharmaceuticals cold, and then surrounded by pharmaceutical grade cold gel packs that were frozen at the outset, we were able to keep the vaccines at the proper temperature throughout the 3 flights to Nairobi. (Syracuse to Detroit 2 hrs, plus layover; then Detroit to Amsterdam 8 hours plus layover; then Amsterdam to Nairobi 8 hours plus layover). Once we reached Nairobi, we had a short "overnight" of about 6 hours at the Mayfield guest house. There we took down the cooler and refroze the ice packs, and checked the temperature. In the morning we repacked the cooler within a cooler with the refrozen ice packs.
The rest you can see from the video: we were ecstatic that the transport worked. And perhaps you'll even be able to see in the video, that on the airstrip Don Cross was careful to move the cooler with the vaccines under the shade of the airplane wing, to keep it a tad cooler as we received the wonderful warm reception from the villagers and staff.
So at the clinic now, we have one refrigerator that will be used only for vaccines. It will be kept locked, and will be monitored for temperature twice a day by our pharmacist. The staff understand that part of the cold chain is that vaccines-only must be kept in that refrigerator, so they will never place any personal items in that refrigerator.
AIM AIR is familiar with the concept and use of the cold chain, and will assist us in any future transport of vaccines or medicines or reagents that use the cold chain. And also the company MEDS in Nairobi that is our medication supplier has its own cold chain system at their company and they are equipped to send us medicines or reagents using the cold chain. Dan Friedman and I got to tour the MEDS facility and see their cold chain. Looking to the future we may be able to do blood transfusions, now that we have the cold chain, as the reagents and blood must be kept cold too, but that will be another refrigerator, and another chapter!
- Dr. Barbara Connor
Don Cross then goes on to explains how they pulled it off technically:
I worked with a variety of solar and refrigeration equipment suppliers
in the US and in Africa to sort out "best practices" and equipment for
Once the funding became available we wasted no time because we already
had a "system" designed (on paper) and once we knew we were going
forward, I was able to earnestly get best prices and secure the purchase
of all needed items through one supplier: Center for Alternative
Technologies - "CAT" in Nairobi Kenya.
We agreed on price- transferred funds and then awaited delivery to Aim
Air freight depot at Wilson Airport in Nairobi on Feb 10th - the day I
left the US to go to Sudan.
I met the CAT engineers at Aim Air on Feb 12th and went over the entire
system including the wiring schematics and was fully briefed on all
parts and their functions prior to loading them onto a Cessna Caravan
which took most of the afternoon.
By 5PM the plane was packed full of the refrigerators, solar panels,
wind turbine, the electronic controllers, the 6 gel cell (100 lb)
batteries, cables, turbine mast, steel framework for the roof, AND 1000
mosquito nets totaling over 1250 kgs. There were only 2 seats in the
plane: one for the pilot and one for me the rest was equipment and nets.
We took off for Sudan early on Friday (Feb 13th) with a planned fuel
stop in Loki.
We landed around 1PM to a big crowd of villagers and clinic staff who
took on the task of carrying all of the equipment and the bags of tools
and my belongings from the airstrip to the clinic about 1/2 mile away. I
have some pictures of all the items being carried by the "human conveyor
belt" procession of men, women, and children in an almost continuous
line stretching from the airstrip to the clinic along a hot dusty
footpath in the midday sun.
I spent the next 2 weeks assembling the components and getting them
mounted, wired, and tested in anticipation of the arrival of REAL
Our temperature limits (per established "cold-chain" protocol) were from
2 to 8 degrees C. (35 to 46 degrees F).
We filled water jugs to simulate a "warm load" and loaded the 8 cu.ft.
fridges and within 4 hours all were below 8 degrees C and they stayed in
the desired range after that - night and day. We are using max/min
digital thermometers with memory to track daily performance and insure
I purposely oversized the solar components so that they would be able
provide electricity even in the rainy season. The first morning after we
started the system, I was in the building checking the controllers and
we were actually generating electricity BEFORE sunup in the early
The wind turbine was really an experiment meant to see if the rainy
season 30 knot + winds will be able yield any meaningful generation. We
did get output in the breezes that daily blew over the clinic, but solar
is so plentiful that any wind power was really not needed.
Should the turbine really give us reliable source of power in the rainy
season we may someday increase size and get one that can actually be
useful for clinic operations.
Our goal is to make the clinic GREEN by adding more solar to run clinic
and also the well pump and remove the need for the diesel generator
(except for emergencies). Of course this will take funding and we are
actively pursuing this at the moment for next year.
- Don Cross
You can read the first part of this series here: