Researchers on Monday announced promising results for a tuberculosis vaccine that can be freeze-dried and safely stored at higher temperatures for months, hailing a major breakthrough in the fight against one of humanity’s biggest killers and a major step towards overcoming one of the big barriers to vaccine distribution in poorer parts of the world.
Key Facts
The temperature-stable vaccine was tested in 45 healthy adults, half of whom were given a different vaccine formula that isn’t stable at higher temperatures and developed by scientists at the Access to Advanced Health Institute (AAHI) in Seattle (formerly the Infectious Disease Research Institute).
The freeze-dried formula, which was stable at temperatures of almost 100F (37C) for three months, was mixed with water just before injection. Volunteers were monitored for six months after receiving two shots given 56 days apart.
The new shot was safe, well-tolerated and successfully elicited measurable cellular and antibody responses, according to trial results published in Nature Communications.
The temperature-stable vaccine also generated higher antibody levels in the blood—a sign, but not proof, of protection—compared to the non-stable shot, the researchers found, noting that the finding is not enough to determine which provides the most protection against TB.
Though further research is needed to test the vaccine, the researchers said the findings are “proof-of-concept” that a vaccine can be freeze-dried and made temperature-stable without dampening safety or its ability to provoke an immune response.
The shot could one day provide an alternative to BCG, the only vaccine licensed against tuberculosis, which is freeze-dried, temperature sensitive, “readily destroyed by sunlight.” It must be reconstituted with a specific liquid that cannot be frozen, conditions that prove challenging to maintain in many, often poorer, parts of the world.
Big Number
1.6 million people. That’s how many died from TB in 2021, according to the World Health Organization. TB has been the leading infectious killer for years after HIV/AIDS, though Covid-19 has overtaken it in recent years. The disease sickened an estimated 10.6 million people in 2021.
Key Background
Tuberculosis is a bacterial infection that often attacks the lungs. It is spread from person to person through the air, such as when someone with TB coughs or sneezes. It has been documented in humans for thousands of years—albeit under different names, including consumption, phthisis and the White Plague—and is one of humanity’s leading killers. It is curable and preventable, though emerging antibiotic resistance could jeopardise this. Vaccination and public health efforts in wealthy countries mean the disease now overwhelmingly affects poorer nations. Health organisations like the WHO and the Bill and Melinda Gates Foundation have made tackling TB a key priority. Only one vaccine is used to protect against TB—the Bacille Calmette-Guérin, or BCG, vaccine—and it has been in use for more than 100 years.
AAHI chief executive Corey Casper said challenges in keeping shots cold worldwide have stymied efforts to distribute vaccines equally. The development is “a major achievement towards our mission of bringing vaccines to people who most need them, regardless of geography,” Casper added.
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What We Don’t Know
The study, supported by the National Institutes of Health, came from a Phase 1 clinical trial. Phase 1 trials are among the most preliminary clinical trials used to evaluate new vaccines and medicines, they typically involve only a small number of people and only test for safety, not efficacy. More comprehensive trials will follow to test how effective the shot is in practice and see whether any other concerns emerge in practice among a larger group of people. Such trials can take years and the majority of drugs tested do not make it to market.
What To Watch For
Further studies are going to be needed to make sure the temperature-stable shot can be effectively and affordably scaled up to make it a viable competitor to other shots on the market, the researchers said. The temperature-stable vaccine will cost approximately $0.15 more per dose than its unstable equivalent, the researchers estimate. However, the higher cost could be overcome by savings and reduced wastage from its less-stringent storage requirements, and they added the technique underpinning its production is already used for many other vaccines already on the market.
This story was first published on forbes.com
