Now that we have possibly viable candidates for the COVID-19 vaccine, the media frenzy has moved on to another plane – how to store and transport vaccines. Especially the Pfizer vaccine, which needs to be stored at -70°Celsius – colder than winter in Antarctica; and the Moderna candidate, which needs a more moderate -20°Celsius.
By Dr Rajiv Pathni
And this, the media speculates, would limit the distribution of the vaccines to only the developed countries which have the required cold-chains. They are probably not aware that the Ebola vaccine, to cite a recent example, also required similar ultra-cold (-80°Celsius) chain storage. And this was successfully implemented in some African countries five years back.
If that doesn’t give you hope, let’s take a trip back in time. Over 200 years back, in fact.
Children
In 1803, a ship set sail from Spain for the New World (Americas and the Caribbean) with a precious cargo –smallpox vaccine.
Smallpox was wreaking havoc on the colonial rulers in the New World and the death rate was anywhere up to 50%. Edward Jener’s discovery of vaccination in 1799 offered a solution. The challenge was how to preserve the vaccine preserve the vaccine during the long voyage. We must remember there was neither refrigerated cold chain nor jet aircraft. So they devised a very ingenious plan.
Twenty-two children were selected to carry the vaccine. Aged three to nine years, these boys were, of course, “wards of the state” i.e. they were orphans. During the journey, the children were vaccinated in pairs. Every ninth or tenth day the consecutive pair was vaccinated by taking lymph from an unbroken pustule from the previously vaccinated boy. And so, through the voyage, the vaccine was kept viable by passing it from one boy to the other every ten days thus creating a vaccine chain. Vaccinating them in pairs was the other clever part of the plan- it ensured preservation of the vaccine in case of a mishap with one of them.
It is estimated that over 100,000 people were vaccinated by the Royal Philanthropic Vaccine Expedition. Over two centuries back they had no modern cold chain, nor any fast jets; only human ingenuity.
Let’s take another example.
Chicken
In the late 70s, in a newly independent Bangladesh, a fresh NGO -Bangladesh Rural Advancement Committee (BRAC) was besieged with a problem. One of their ventures was to support poultry farming under which chicken were to be vaccinated against a common disease. They had vaccines but didn’t have a robust cold chain to carry it to the rural hinterland. In the absence of technology, they hit upon a very simple solution. The vaccine ampoule taken from the refrigerator would be inserted inside a banana. The fruit provided the insulation needed to maintain the ampoule at the required temperature through the journey. As an added advantage, it also prevented breakage of ampoules during the long journeys over rough rural terrain.
Again- no technology, just some homespun jugaad!
Let’s look closer home.
Straws
The Indian dairy industry records almost 8 crore artificial inseminations (AIs) across the country annually. This involves collecting semen from elite bulls in 56 ranches, which is then frozen in “straws” and transported at -196° Celsius across the country.
Along the way the straws are transferred from the bulk containers to small 3 litre containers which are carried on motorbikes or cycles to the farmers’ doorstep. The coolant used is liquid nitrogen – a by-product of the liquid oxygen plants. It is also sourced from fertilizer plants. Each time the container is opened to take out a straw, some liquid nitrogen escapes. So reserve stocks of liquid nitrogen are maintained at their district centres to replenish the containers.
Closing Note
Fact is that transportation of biologicals has always deferred to human ingenuity through time, history and geography. Over 200 years ago, in the era before refrigeration and jet aircraft, smallpox vaccine was carried around the globe on the person of small boys. More recently in the 70s a cold chain was maintained without any technology – using the humble banana.
And WHO can claim, with a clear conscience, that neither boys nor bananas were harmed in the transportation of Ebola vaccine. They used jet fuel (easily available) to maintain the temperature of -80° C.
The naysayers will talk about scaling and lack of requisite technology in India. They need only look at the well-established cold chain in the dairy sector which is already transporting 80 million (8 crore) doses at-196° Celsius all over India. This is way below the -20°C or -70°C required by Moderna and Pfizer. The supply chain for liquid nitrogen, which supports this venture, is also well established – down to the district distribution level.
Can it be used for vaccines? Certainly. Adaptation, replication and scaling-up of this existing supply chain will be very simple.
Rest assured the challenges to Covid vaccination will not come from the requirements of the cold chain.
This article first appeared in www.vifindia.org and it belongs to them. The author is a research associate with VIF.
