Polio vaccine can successfully prevent the deadly paralyzing illness caused in children. The vaccine presently available is in liquid form and is also thermolabile.
This means that when exposed to higher than recommended temperature at any point in its transit the vaccine loses its efficacy despite being cooled again.
Researchers have come up with a freeze-dried form of this vaccine that can be stored as dried powder at room temperatures.
Human poliovirus computer model. Poliovirus infects children and causes poliomyelitis, a disease which in severe cases damages the nervous system, leading to paralysis or death. Image Credit: vitstudio / Shutterstock
This could help eradicate the disease say the researchers. The results of their study on the new version of the vaccine titled, “Development of Thermostable Lyophilized Sabin Inactivated Poliovirus Vaccine,” was published in the latest issue of the journal mBio.
Polio virus is highly contagious and spreads among children of densely populated and remote locations where the presently used vaccine is unable to reach. This includes regions in Nigeria and Pakistan that could benefit from the vaccine and help them eradicate the infection that may lead to life-long paralysis and even death.
The oral vaccine that is used in present uses weakened form of the live polio virus. This weakened virus can help the children who are vaccinated to develop an immunity against the infection. There is another form of the vaccine – the injectable polio vaccine – IPV. This contains dead strains of the virus and this can be stored at temperatures below about 4C (39.2F).
This new vaccine is the freeze-dried form of the IPV. This new version of IPV can be stored at higher temperatures of up to 40C for four weeks. The vaccine can then be reconstituted for use. The drug retains its potency.
Woo-Jin Shin, a co-author of the report from the Southern University of California said in a statement, “We freeze-dried inactivated polio vaccine and during the freeze-drying we added some ingredients that make it more stable.”
The team of researchers worked from Southern University of California along with support from a company called Integrity Bio Inc. They created this new formulation using magnesium sulphate, amino acid histidine, and the sugar mannitol that stabilized the preparation.
The vaccine was stored at different temperatures. It was then reconstituted and administered in mice. It was seen that the vaccine was still potent after four weeks of exposure to elevated temperatures the researchers wrote. This would mean the charitable foundations working in remote locations where it is difficult to maintain cold transit, could help the populations better write the researchers.
“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,” said Dr. Shin. Polio virus can be transmitted from person to person mediated by direct contact, food and contaminated water. The infection itself may be mild or non-symptomatic but in around 0.5 percent it may cause paralytic disease that may cause a lifelong disability write the researchers.