South Africa: Vaccine cold supply chain can’t reach anywhere

In many countries, vaccines that need to be kept very cold are not available, causing major problems with fair Covid-19 vaccination.

To alleviate health inequality and promote social justice, coronavirus vaccines need to reach underserved people and hard-to-reach communities.

There are few places in the United States that are out of reach by road, but other factors (for example, many local hospitals may not be able to buy ultra-low temperature freezers or may not have reliable electricity) are at stake. But with the will and resources of the government, these can be overcome.

That is not the case in many other parts of the world.

One of us, Tim Ford, is a global health researcher who has recently conducted many international studies on water and health in the countryside of Haiti, where the cold supply chain is underdeveloped. Another, Charles Schweik, is studying how the proliferation of both digital and physical innovation can solve imminent social problems and social inequality.

Pfizer and Moderna vaccines are a great start to celebrate, but they rely on the complex supply chain of the freezer and a temperature-controlled transportation method called the “cold chain.” Reliance on cold chains raises concerns about fairness and social justice, as many parts of the world cannot support cold chains. Researchers are working hard on vaccines that can avoid the logistical and financial nightmares of cold chain delivery.

Where the cold chain does not advance

There is no mechanism to keep vaccines cold in poorer areas, in more remote parts of the world, and in areas with high average daytime temperatures and uneven electricity availability. In fact, many of these places may not have roads, let alone airports. Also, even if roads exist, they may not be accessible at certain times of the year, or may be inaccessible due to political reasons or public unrest.

Both the Moderna and Pfizer vaccines need to be stored frozen and need to rely on the cold chain to go anywhere. Only large wealthy countries have the resources to implement a well-developed cold chain. This means that most of the world is currently unable to get the Covid-19 vaccine.

This has a negative impact on public health and is not fair and impartial.

Temperature stable vaccine

Vaccines that do not require cryopreservation have appeared. Some companies, such as AstraZeneca and Johnson & Johnson, are working on vaccines that only require refrigeration rather than storage at freezer temperatures. In late December, the AstraZeneca vaccine was approved for use in the United Kingdom. Both vaccines should be available on the global market in the coming months and have the potential to significantly expand the range of vaccines.

The two companies are also working with the Covax Facility, which claims to be a “global risk-sharing mechanism for pooled sourcing and fair distribution of the final Covid-19 vaccine.” The goal is to make the vaccine available to all countries participating in the Covax program, regardless of income level. As of mid-December, 92 low- and middle-income countries are registered.

Refrigeration is better than freezing, but room temperature is optimal in remote areas, and researchers are working on a heat-resistant Covid-19 vaccine that does not require refrigeration. Technology that eliminates the need for a cold chain of vaccines has been used and successful for decades. The freeze-dried vaccine is one example. The first thermostable vaccine was developed for smallpox in 1955 and partially contributes to the final elimination of the disease.

Today, researchers continue to look for innovative ways to stabilize viral vaccines. From low-cost sugar membrane air drying to freeze-drying with various stabilizers. Some researchers are also working on stable liquid formulations, especially the live-attenuated influenza virus, avoiding the costly process of lyophilization, which is not always easy for low- and middle-income countries. All of these approaches are applicable to live virus vaccines that use attenuated viruses, such as influenza vaccines, and to both coronavirus vaccines being developed by AstraZeneca and Johnson & Johnson.

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So far, this is mostly basic research, but progress in this area will greatly help meet global health needs.

To date, the most promising efforts towards a temperature-stable Covid-19 vaccine are from groups in China and India. Chinese scientists have developed a method of wrapping an mRNA vaccine in lipid nanoparticles and keeping it fresh at room temperature. Indian researchers are using engineered protein fragments that are resistant to high temperatures. Most recently, a British team has begun collaborative research on polymer-stabilized, needle-free solid vaccines.

Given the limitations of the cold chain, there are public health, moral and ethical obligations that require investment in vaccines that can be provided using a non-cold chain approach. For people in many places, it is the only way they can be vaccinated.

This article was first published in The Conversation.