Powdered polio vaccine brings hope to Nigeria and Pakistan | Society

A polio vaccine that can be stored as a dried powder at room temperature could offer a new way to help eradicate the disease, according to researchers.

While existing vaccines have led to polio being eliminated in many countries around the world, including the UK, the highly contagious virus still circulates in the populations of countries including Nigeria and Pakistan, where it can cause paralysis or even death.

However, oral vaccines use a weakened live virus that can, occasionally, transform into a version of the virus that can cause paralysis. As a result, there is a push to introduce another type of vaccine called inactivated poliovirus vaccine (IPV), which involves an injection containing dead strains of the virus.

While this has already happened in many countries, one big barrier to widespread use is the sensitivity of IPV to temperatures above and below about 4C (39.2F).

Now researchers say they have managed to develop a way of freeze-drying IPV, such that it can be stored at elevated temperatures of up to 40C for four weeks and then dissolved for use – without losing its potency.

“We freeze-dried inactivated polio vaccine and during the freeze-drying we added some ingredients that make it more stable,” said Woo-Jin Shin, a co-author of the report from the Southern University of California.

Writing in the journal mBio, Shin and colleagues from the Southern University of California and a company called Integrity Bio Inc describe how the formulation includes among its ingredients magnesium sulphate, the amino acid histidine, and the sugar alcohol mannitol.

The researchers then stored the dried vaccine at different temperatures and looked at how levels of particular antigens changed over time, as well as testing the vaccine on small groups of mice, with both types of experiments suggesting little change in potency of the vaccine when stored for four weeks, even at elevated temperatures.

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Shin said he hoped the approach would be picked up for use by charitable foundations.



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