Super-engineered vaccines could end polio

Posted on the 11th July 2023

Scientists from the USA and UK have created ‘super-engineered’ vaccines that could spell the end of polio.

The oral vaccines contain weakened live polio viruses and work by locking them into a weakened state, preventing them from mutating into a dangerous form that can cause outbreaks and paralysis.

Polio can spread into the nervous system, causing paralysis. Cases have fallen by more than 99 per cent since the late 1980s and about 20 million people who would have been paralyzed can walk thanks to vaccines.

However, there are still issues with the supply of the vaccines to some of the areas in need of them most.

The original or "wild" poliovirus is now contained to small pockets of Afghanistan and Pakistan and the oral vaccines play a pivotal role in the attempt to rid the world of polio.

Concerns have been raised over the genetic stability of some of the oral vaccines as it takes only one mutation to turn the safe polio vaccine back into a virus that can move out of a child's stomach, invade their nervous system and cause paralysis.

Additionally, should those viruses spread from an immunized child - through their contaminated faeces - there is a risk of infecting the unvaccinated and triggering an outbreak.

There are now more cases of "vaccine-derived polio" than of the wild poliovirus and the polio detected in London's sewers last year was connected to the oral vaccine.

The researchers have now genetically altered the weakened virus even further to make it much harder for it to start causing paralysis again.

In March 2021, the World Health Organization made the researchers' vaccine against type 2 polio available for emergency use. Since then, it has been used more than 650 million times.

Now, in the journal Nature, the researchers have detailed the creation of stable vaccines against polio types one and three.

The first-stage human trials of the upgraded vaccines have already been conducted and researchers say the data, which is still being analysed, is "very promising.”

The trio represents the first new polio vaccines in 50 years.