Vaccines and a Spoonful of Sugar

A good cold chain and some reliable electricity production, as well as reliable drug fridges are pretty important out bush. I’ve even written a few posts on the subject (listed at bottom of post). I even have a couple in draft form so watch out!

vaccinationI was very interested in this news article Spoonful of sugar helps the medicine keep cool. There is a lot of work being done on a couple of viruses, pox and adenovirus to be able to use them as a platform for a range of other vaccines including HIV-Aids, tuberculosis and malaria.

Live vaccines need to be refrigerated. And of course the parts of the world where these diseases are most prevalent are the more remote and poorest areas without electricity.

By using a couple of sugars currently used as biological stabilisers, and slowly drying this virus-sugar mix they can vitrify (basically wrap it in “glass”) the product so it retains its stability without refrigeration at up to 45C for six months. You then take it to the remote location, reconstitute and start vaccinating. Now this has only been done in a lab but is exciting for the future.

Of course it will change the way we handle vaccines around the world, not just in the Third World. Out bush our temperatures during transport can get quite high. This graph is the temperature monitored by a data logger on it’s way from remote central Australia to Tasmania.

graph showing temperatures reached during transportation

It will also dramatically cut costs. The World Health Organisation estimates it costs 20% more than other drugs in cold chain transfers and storage (logistics).

Out where I am we might have a refrigeration mechanic out every few months. He may or may not have the right parts. If not, we wait a month until they arrive and then another few months until a refrigeration mechanic is out again. I try to minimise this delay by having a number of spares already out bush to be available when required.

But I’m in a first world country and can afford to do this.

Reference: R. Alcock, M. Cottingham, C. Rollier, J. Furze, S. D. De Costa, M. Hanlon, A. Spencer, J. Honeycutt, D. Wyllie, S. Gilbert, M. Bregu, A. V. S. Hill, Long-Term Thermostabilization of Live Poxviral and Adenoviral Vaccine Vectors at Supraphysiological Temperatures in Carbohydrate Glass. Sci. Transl. Med. 2, 18ra12 (2010).

Other Cold Chain Posts::
Cold Chain
Cold Chain 2
Data Loggers

Data Loggers

Warning: This post is for those with a fetish for dataloggers.

I had a couple of enquiries about what sort of data loggers I use for Quality Assurance. So here we go.

I have yet to find the perfect data logger. I have used several and haven’t been 100% happy with any of them.It seems I will have to use different loggers for different tasks.

We have 11 clinics with multiple fridges in each clinic. Loggers are to go at random in fridges and also be placed on stock shelves. Loggers are also in the doctor emergency bags which spend a lot of time in and out of hot vehicles. We source pharmacy supplies from several different pharmacies/pharmacy departments depending on item and destination of delivery and our internal mail bags also carry some items. I have already posted about the temperatures our cold chain needs to handle while in light aeroplanes and also how we are starting to move refrigerated drugs around the lands

What do I want in a Data Logger?

    1. Store data from six weeks of readings every couple of minutes.
    2. Alert light (when close to max/min)
    3. Warning light for when temperature moves below or over the required temperature
    4. Warning alarm (optional)
    5. Splashproof
    5. On/off button
    6. Reasonable price
    7. Handle a wide range of temperatures (most loggers can do up to 50C)

TinyTag Loggers

(from Hasting Data Loggers)

These are splashproof and have no plugs, rather using an induction pad. They can be started on delay or using a magnet and they automatically stop after a certain number of readings, or when full. Unfortunately they only take 8000 readings so do not suit my needs monitoring drug rooms and fridges.

Being splashproof they are ideal for use in eskies as we bring refrigerated items onto the lands. However, an inability to switch the item off when received at the clinic makes them of no use. My aim is not to have extra software and plugs at clinics as I use the data for quality control purposes, not just to monitor the temperature integrity during transport. There is also no alarm to indicate the temperature has been too high or low.

TransiTempII

(from Madgetech)

These are good value. Unfortunately they have no push button start/stop but rely on computer software or a magnet to commence and cease temperature recording. This makes them unacceptable for use with third parties starting them in a pharmacy and then a nurse stopping the logger before forwarding it on to have the data used for Quality Assurance purposes.

They do hold over 32000 readings and are splashproof. There are warning and alert lights. A green light signifies the logger has stored temperatures between the set temperatures. There is amber warning light and red alert light. For refrigerated items I have them set for a warning light at 3 and 7C and the alert light to flash below 2C or 8C.

I will continue to use these for long term monitoring where I can download data on a regular visit.

Temp 100

(from Madgetech)

These have an on/off switch! However they are not splashproof so cannot be used in fridges or refrigerated items in transit. We have used these in a drug room data logging project. High and low limits can be set with an LED going from green to red should the limits be exceeded. They are also a lot more expensive than the TransitempII. we will not be using these again.

It seems to have the benefit of an on/off switch and be splashproof I may be up for several hundreds of dollars each meter which will limit the numbers we be able to use to monitor goods in transit.

Using a variety of loggers means there is a variety of software and a variety of cables required, even sometimes if the profit is from the same company. Purchasing from one company will make it easier to have the loggers recalibrated on a regular basis.

Unfortunately the use of the loggers will not replace the use of the chemical heat and freeze indicators in the drug fridges. I have come across several incidences where the fridge temperature readings have been normal, but items frozen, or overheated at the top or bottom of the fridge. This can occur due to fan failures or temperature probe failures.

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Cold Chain II

Maintaining the cold chain is difficult out bush. I wrote in August about the high temperatures reached in the planes transporting our pharmaceuticals. Power failures are regular in many remote communities and can lead to failure of the cold chain rendering the vaccines and other refrigerated items unusable. Over time I have built up a reasonable database of various drug stabilities at higher temperatures. However many of these studies do not reflect the temperatures to which these drugs may be exposed to.

These community generator power failures often necessitates removing these drugs in a safe and approved manner from these communities and replacing them quickly. This often means items transported from another community.

from "Strive for 5" guidelines 2005We could use foam containers and freezer blocks. During summer the ideal method is that mentioned (p31) in the “Strive for 5” vaccine storage guidelines, placing a polystyrene container in a much larger cooler and surrounding the container with freezer blocks or using a specialised vaccine cold box as recommended by the WHO.


Some emergency missions to overseas disasters have used large portable fridges. However these have needed careful monitoring with certain drugs placed in certain areas and adjustments to the thermostat if numbers of items are removed. Whilst these are good for setting up a remote emergency clinic they do require some specialised knowledge to maintain the correct storage for various drugs.

I have been trialling a new portable refrigerator. It has a volume of 25 litres which allows us to transfer adequate quantities of drugs urgently to a clinic until bulk supplies arrive in a week or two by plane.

Twinbird Vaccine Fridge
Twinbird Vaccine Fridge

We obtained the Twinbird from Rollex Group Australia. While considerably more expensive than say an Engel, it performs very well.

I have been using it for several months monitoring temperatures with a third party data logger. The temperature monitoring and alarm system seem quite accurate. The fridge does use a different sort of cooling system than the compressor style, allowing more accurate temperature control. There are two baskets inside the refrigerator so there is no direct contact by the vaccine or blood products with the sides where they may freeze.

The power cord could be more robust, and it requires an optional DC converter to run inside on AC power (Engel etc require just a separate cord to plug into the unit). It is light, but seems quite solid and has handled rough bush trips with ease.. I would have liked some way to be able to lock the fridge. It also now comes with a printer option for temperature recording and I will be including this option in future purchases as we expand our on-lands logistics capability.

But then I think we have it easy compared to some locations around the world! This is the Vaccine Fridge CFS49IS System with CFS standing for “Camel Fridge System”.

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Cold Chain

Daniel Grabek
Daniel Grabek

For some time I had been trying to have some research done on our cold chain. Not only for our refrigerated items, but items stored on the shelf in drug rooms.
Honours student, Daniel Grabek from UTAS came to the rescue with his honours thesis “Stability of medicines stored in remote outback settings”.

We had some monitors for a while sitting in our drug rooms faithfully recording all the temperature spikes as community generators started failing in different communities. The most interesting though was the temperature reached when goods were flown in an out (our only access for medications).

A data logger was not switched off and recorded temperatures as it bounced off down to Tassie with Australia Post. The highest spike was in transit by plane from the community. It reached 56C and took over 8 hours to fall below 25C when placed in a cool room.

These are the temperatures our refrigerated products have to handle in transit. We have very few breaches of the cold chain.

However the temperatures reached should be of concern for mail-order pharmacy and even delivery of goods on the back of trucks in summer, particularly in the country.

I have just taken possession of 8 data loggers and are going to use them to monitor everything from doctors bags to drugs in transit as part of our QA.

I look forward to seeing Daniel’s completed thesis

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