Researchers at Ecole Polytechnique Federale de Lausanne‘s Supramolecular Nanomaterials and Interfaces Laboratory claim they have developed methods for 3 vaccine additives to help store vaccines at room temperature. The team’s work was published in Nature Communications. 

The need to keep vaccines within a temperature range of 2-8°C contributes to low immunization-coverage rates, because shipping vaccines in an unbroken temperature-controlled supply chain is a logistical and costly endeavor in remote areas. But this team of researchers say they have devised a way to use small quantities of nanoparticles, FDA-approved polymer, or higher amounts of sucrose to stabilize the medicines at room temperature for long periods of time.

Viral-vector vaccines, the most common kind, normally last for a few days at room temperature before the viral components of the vaccine loses its structural integrity. “These components fluctuate by their very nature,” head of SUNMIL Francesco Stellacci said in prepared remarks. “They are combined in a stable form, and the low temperature maintains that balance. But the thermally induced fluctuations eventually lead to a loss of integrity of the viral vector.”

The team found that negatively charged nanoparticles could apply osmotic pressure on the inactivated viruses, countering the outward osmotic pressure built up within the virus from its genetic material. The counter-osmotic pressure keeps the virus intact.

The 2nd additive, polymers, were added to the virus’s capsid. The capsid, which envelops the inactivated virus, stiffens and slows the virus’s oscillations.

Finally, the team added sucrose to the vaccine, making the environment more viscous and slowing down fluctuations. “It’s a little like adding honey, where all motion is slowed down,” Stellacci said.

The researchers tested their methods on a vaccine in development for a tropical virus known as Chikungunya. Using their techniques, they were able to stabilize the vaccine for 10 days and then successfully inoculate mice with it. “The next step will be to run more extensive tests on specific vaccines, possibly combining the three different approaches,” Stellacci said.