Researchers at University of South Carolina (USC) have developed a polio vaccine that doesn’t need refrigeration. This development could go a long way in helping mankind finally eradicate the disease, as one of the reasons it continues to persist today is because many high-risk areas don’t have steady access to electricity or cold storage facilities.
Researchers initially used liquid chromatography and high-throughput screening to analyze the vaccine’s ingredients. Once this step of the process was complete, the vaccine was freeze-dried into a powder, kept at room temperature for four weeks and then rehydrated. When it was tested in mice subsequently, it offered full protection against the virus.
“Stabilization is not rocket science, so most academics don’t pay much attention to this field,” said the study’s first author, Woo-Jin Shin. “However, no matter how wonderful a drug or vaccine is, if it isn’t stable enough to be transported, it doesn’t do anyone much good.”
Researchers have previously created freeze-dried, temperature-stable vaccines for measles, typhoid and meningococcal disease.
Pakistan is one of the three remaining countries in the world where polio is still categorized as an endemic viral infection. The other two are Afghanistan and Nigeria.
Though Pakistan has made significant progress against the virus, progress continues to be hindered due to a variety of factors, including lack of cold storage facilities and mobile cold storage facilities.
Speaking to MIT Technology Review, a UNICEF media officer explained, “currently vaccines have to be flown to Islamabad directly from manufacturing plants, and then placed in cold storage before being dispatched to warehouses in districts all over the country in specialized cold storage vehicles. From here, the vaccination teams have to go door-to-door, delivering vaccines using coolers with ice cubes.”
“Maintaining this ‘cold chain’ in the summers is exceedingly difficult,” he added, “temperatures in parts of Punjab, Sindh and Balochistan can reach 50 degrees celsius, while the vaccine must be kept between zero and eight degrees celsius.”
The more remote the location, the more difficult it is to maintain the cold chain, as this increases the likelihood of mobile cold storage systems failing. Batches would be particularly vulnerable in the final stages of the drive when vaccinations are being delivered door-to-door. Administration of spoiled or expired vaccines could not only fail to protect against the virus, it can be dangerous in and of itself. According to reports in the media at least three children died in Peshawar in April this year, while four others were hospitalized because of expired polio vaccines.