The unsung virtue of thermostability

The current vaccination campaign against SARS-CoV-2 has many challenging aspects, one of which is maintaining the cold chain for the distribution, delivery, and storage of available vaccines and guaranteeing that their full titre is retained for administration. Although outstanding technology for vaccine development has enabled products to be put on the market in 1 year, it is difficult to understand why approximately the same length of time is taken to roll out their administration, thus jeopardising the effect of the campaign. Additionally, if a substantial proportion of vaccines lose their potency or safety, or both, because of problems during transportation and storage, they will be less efficacious, and an increase in the overall costs of deploying the campaign will be inevitable. The reason for having to implement the cold chain is that thermostable vaccines do not exist (ie, heat-stable and freeze-stable, so as to be stored at a temperature of >8°C, which is a preferred vaccine characteristic recommended by WHO).¹ No COVID-19 vaccine exists in a format that could be delivered to homes by mail and, ideally, self-administered.

In actuality, high-income countries were not really interested in and committed to developing thermostable vaccines, because this feature was never expected to become a major hurdle in the limited scope of scientists. There was a failure to identify any foreseeable circumstances under which high-income countries would not have enough refrigerating capacity to manage any widespread vaccination campaign. For this reason, developing thermostable vaccines was never a priority or a core requirement for high-income countries. In fact, the real demand and insufficient push for thermostable vaccines, both in veterinary and in human medicine, comes from low-income and middle-income countries and, although supported by international organisations, it was never prioritised to become an essential characteristic sought by vaccine developers, industries, and funding entities.

Perhaps investing in global needs, which include the needs of the poorest people, would have benefited the whole of humanity in tackling the COVID-19 pandemic. Now is the time to reprioritise the urgent improvements in vaccine development that are essential to fully make use of the power of immunisation campaigns even under diverse epidemiological, geographical, and logistical circumstances.

We declare no competing interests.