Researchers have found a way to tweak vaccines so that they could be stored at room temperature, making them significantly cheaper to produce and distribute.
Scientists have developed a new method that they believe could cut the cost of making and transporting vaccines by “by about 80pc”. Researchers in Mexico said their technique can also be used to produce vaccines that can be stored at room temperature and have a longer shelf life.
At present, all vaccines follow a cold chain procedure that requires refrigeration at all times, from the manufacturing stage to the point of administration. This, the researchers said, can be a costly process and pose a problem for low-income countries and remote areas with no electricity.
Even with temperature-controlled storage, most vaccines have a short shelf life, often as little as a few months. In addition, many vaccines rely on substances called adjuvants to boost the desired immune response, which may cause allergies and other unwanted side effects.
The scientists say their findings, published in the journal BMC Biotechnology, opens up the possibility of developing vaccines that generate a sufficient immune response without the need for an adjuvant or refrigeration.
Luis Vaca, of the National Autonomous University of Mexico and one of the study authors, said: “The vaccines that are currently available require constant cold storage, meaning they rely on a temperature-controlled supply chain, which constitutes over 80pc of their cost.
“We have developed a novel technology to produce vaccines which require no refrigeration and have a shelf life of many years.”
Learning from insects
Vaca, along with a team of researchers, followed a strategy that insect viruses use, which allows them to survive outside of their host for extended periods of time. These viruses have been found to utilise a protein known as polyhedrin, or PH(1-110), which shields them from the environment by forming tiny protective crystals.
To investigate the possible usefulness of PH(1-110) as a vaccine carrier, the researchers combined it with another protein called the green fluorescent protein (GFP), which is known to generate a weak immune response, and created PH(1-110)GFP crystals.
Tests on mice showed a “strong immune response” when injected with the PH(1-110)GFP crystals. This response, according to the researchers, was similar to one observed in mice injected with GFP and an adjuvant.
The antibodies produced by the vaccines remained in the blood of the mice after 24 weeks, indicating the production of a lasting immune response, the researchers said. To test the longevity of the PH(1-110)GFP crystals, the authors stored the substance at room temperature in dry powder form.
When injected in mice 12 months later, the vaccines generated antibodies. Vaca said: “As PH(1-110) could be paired with any protein, our technology opens up the possibility of reducing the cost of conservation and distribution of vaccines by about 80pc – the cost of the temperature-controlled supply chain.”
Commenting on the research, Jimmy Whitworth, a professor of international public health at London School of Hygiene & Tropical Medicine, who was not involved in the study, said that there are some “encouraging aspects” to the research, although the findings are mainly preliminary.
He added: “The vaccine induced robust immune responses in mice that persisted for six months.
“So, all in all, promising – and definitely worth following up to demonstrate its stability at relevant temperatures, that it works with a variety of vaccine constructs, and that it induces immune responses in humans.”
– PA Media