It is 40°C outside. The power supply for the refrigerator is unreliable as the electricity either fails or the voltage fluctuates, and there is no fuel for the generator. The person who monitors the temperature of the health unit’s refrigerator – the one storing vaccine vials for tomorrow’s immunization session – is out sick and the ice packs are already starting to melt.
How do you keep the vaccines cold? How do you know the vials have not been exposed to heat? Can you still transport them safely to a neighbouring community 20 kilometres away? And how do you transport them?
These were challenges that John Lloyd, an architect by training, noticed as he began his career designing hospitals in different countries in the early 1970s.
An architect of the vaccine cold chain
Frustrated by the lack of healthcare access for poorer communities, John took a sabbatical from architecture to study primary healthcare facilities in Kenya and Tanzania. During his sabbatical, he discovered that inadequate vaccine storage infrastructure was leading to vaccines losing effectiveness in high temperatures.
Around the same time, in 1974, WHO established the Expanded Programme on Immunization (EPI) to provide universal access to protect all children against 6 childhood illnesses – tuberculosis, diphtheria, tetanus, pertussis, polio, and measles. With EPI, WHO and countries were also encountering similar challenges to safely store and distribute vaccines.
Based on his findings from Kenya and Tanzania, WHO hired John, along with other experts, to collaborate with the Government of Ghana – an early adopter of EPI – to develop and test a new cold chain system and technologies that could be used to keep vaccines stored at safe temperatures and be delivered to health centres.
Working with the Ghana health authorities, John quickly discovered that domestic refrigerators and picnic boxes made in Europe could not compete with 40°C heat nor the long shipment. Most were damaged on delivery, and spare parts would be difficult to find. Since all but one of the original EPI vaccines were sensitive to heat and a few sensitive to freezing, there needed to be a way to monitor storage temperatures to keep the vaccines effective.
In 1977, John published a strategy paper outlining Ghana’s first vaccine cold chain and how this could be replicated in a low-income country. This model was later reproduced and adopted by like-minded logisticians, immunization managers, and cold chain experts and implemented globally.
As part of the strategy, he envisioned a system that managed to keep vaccines at the correct temperatures from the point of arrival in the country, usually the national vaccine store in the capital city, all the way to the health facility or immunization campaign site. However, John and other experts were still concerned that vaccine vials could be exposed to too much heat throughout the journey rendering them ineffective.
By the late 1970s, John and other WHO consultants began working with PATH to track the heat exposure of individual vaccine vials. Their contributions later led to vaccine vial monitors, a heat sensitive label that changes colour progressively each time the vial is exposed to temperatures which are too high. Today, these monitors are affixed on all vaccines produced by UNICEF for global immunization programmes.
A vaccine vial monitor on a bivalent oral polio vaccine vial. Credit: WHO / Rod Curtis
“John’s journey from hospital architectural design to healthcare development in low-income countries is a testament to his unwavering determination and compassion. His work has transformed the lives of many and serves as a shining example of what can be achieved when one is driven by a noble cause. This was just the beginning,” said James Cheyne, a former WHO EPI Technical Officer.
Always ahead of the game
Over John’s 25 years at WHO, he convinced several companies to design and manufacture the needed equipment based on his original cold chain strategy and the challenges he continued to encounter in various countries. His work led to the development of new and improved cold boxes, vaccines carriers, multi-energy refrigerators, ice-lined refrigerators, and solar-powered refrigerators.
Later his focus stretched to other challenges facing immunization programmes. By the 1980s, reports of unsafe injection practices, syringe re-use, and needle-stick injuries increased, which exposed health workers to infection. John collaborated with other agencies to increase awareness of the risk and worked to encourage companies to develop auto-disable syringes that automatically locked down the syringe’s plunger after an injection.
WHO-recommended auto-disable syringes are now available at a low-cost routinely and procured and delivered by UNICEF for the vaccination of children worldwide. He also worked to develop inexpensive cardboard safety boxes that health facilities use to store used needles and prevent needle-stick injuries.
Developing human resources to manage and implement the immunization supply chains was also a part of John’s legacy. In 1989, he launched TechNet, which began as a group of experts committed sharing best practices on strengthening immunization. Today, the group has evolved into a global immunization network of immunization professionals committed to strengthening immunization services by building relationships, sharing knowledge, coordinating activities, and aligning priorities and goals.
Beyond improving the immunization supply chain, John was instrumental in launching the Kick Polio Out of Africa campaign with the African Football to raise awareness and funds for polio eradication. He designed the "Kick Polio Out of Africa" logo with his daughter, polio vaccine "day carriers”, and a stool-specimen collection kit. He also wrote a popular regional polio eradication song sung by Koffi Olimode of the Democratic Republic of Congo.
The “Kick Polio Out of Africa” vaccine carrier being used in the Bredjing Refugee Camp in Chad in 2024. Photo credit: WHO / Jean-Marc Giboux
John’s story shows what can be done through vision, collaboration, and support among different partners and agencies. Throughout his career, John worked with WHO, UNICEF, governments and other partners to ensure vaccine safety, to provide equal access to vaccination, and to adopt new innovations to improve immunization services. He worked with a team of committed logisticians, immunization managers, and industry partners who continue the work to achieve this vision.
Today, millions of vaccine doses are delivered in the right quantities, at the right times and at the correct temperatures to protect tens of millions of children each year from vaccine-preventable diseases, thanks to the work of John and all those he collaborated with throughout his career.
“John Lloyd is one of these unsung heroes of public health who was never in the news. He has remained discrete, silent and humble and never stopped being innovative, creative and committed,” said Michael Zaffran, Retired Director, Polio Eradication at WHO.
John Lloyd (center) and all of the original cold chain crew who worked together ensure vaccines remain effective throughout the supply chain. Photo courtesy of Photo courtesy of Anne McArthur-Lloyd
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This story is to commemorate John Lloyd’s significant contributions to the Expanded Programme on Immunization. John Lloyd died on 17 April 2024 and is survived by his wife, Anne McArthur-Lloyd; and daughters Cressida Eatson-Lloyd and Zoë Ewart.
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