To mitigate health inequities and promote social justice, coronavirus vaccines need to get to underserved populations and hard-to-reach communities.
There are few places in the
That is not true for much of the rest of the world.
One of us,
The
Where the cold chain doesn't go
In poorer areas, more remote parts of the world and in places where the mean daytime temperature is high and electricity is unavailable or spotty, there are no mechanisms to keep vaccines at low temperatures. There may in fact be no roads - let alone airports - in many of these places either. And even if roads exist, they may be impassable at certain times of the year or inaccessible for political reasons or because of civil unrest.
Both the
This is bad for public health and fails to be equitable and just.
Temperature-stable vaccines
Vaccines are coming that do not require ultralow-temperature storage. Some companies, including
Both companies are also working with the COVAX Facility, which describes itself as "a global risk-sharing mechanism for pooled procurement and equitable distribution of eventual COVID-19 vaccines." The goal is to make vaccines available to all countries participating in the COVAX program, regardless of income levels. As of mid-December, 92 low- and middle-income countries have signed up.
Refrigeration is better than freezing, but for remote locations, room temperature is best, and researchers are working on thermostable COVID-19 vaccines that won't need refrigeration. Techniques that remove the need for a vaccine cold chain have been used for many decades with success. Freeze-dried vaccines are one such example. The first thermostable vaccine was developed for smallpox in 1955 and is credited in part with the ultimate elimination of the disease.
Today, researchers continue to look for innovative ways to stabilize viral vaccines: from air-drying with low-cost sugar films to freeze-drying with different stabilizing agents. Some researchers are also working on stable liquid formulations, in particular live attenuated flu viruses, that avoid the costly process of freeze-drying, which is not always easy for low- and middle-income countries to do. All these approaches could be applicable to live virus vaccines that use an attenuated virus, just like the flu vaccine, as well as both of the coronavirus vaccines under development by
Hope for COVID-19 vaccines?
So far, this is mostly basic research, but progress in this area would greatly help meet global health needs.
To date, the most promising efforts toward temperature-stable COVID-19 vaccines come from groups in
Given the limitations of the cold chain, there are public health, moral and ethical obligations that require investment in vaccines that can be delivered using non-cold-chain approaches. For people in many places, that is the only way they will ever get a vaccine.
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