A team of virologists from the University of California presented promising Phase 1 clinical results for a new stable oral polio vaccine. No such vaccine has been considered for 50 years.
Eradicated at 99% by immunization, polio, an infectious disease that can cause paralysis, persists in some countries, particularly in Ghana and Cameroon. To address this, clinical trials are being conducted under the direction of virologist Raul Andino of the University of California, San Francisco.
The aim is to develop a vaccine that is administered orally and is “stable”, i.e. not capable of developing the ability to cause disease in humans. In a study conducted in 2017, the same researchers showed that in order to go from being a harmless vaccine to a threat, the virus responds to three different phases of evolution.
Poliomyelitis is mainly transmitted via the fecal-oral route, i.e. a person becomes infected when they put something contaminated in their mouth (finger, object, food). When a person becomes infected, the virus multiplies in the intestines.
Phase 2 of trials are currently underway
The study published this week in Cell Host and Microbe presents the results of a double-blind phase 1 clinical trial conducted on 15 adult volunteers at the University of Antwerp, Belgium. The study is based on a genetic method developed on the basis of years of research into the biology of polioviruses. The idea was to transform the vaccine in such a way that it cannot go through the three steps that make it so virulent.
The study showed that the new polio vaccine was both more stable and more effective than the 50-year-old Sabin vaccine from which it was derived. In particular, the new vaccine enabled participants to produce multiple antibodies against the polio virus, and despite the excretion of virus particles from the feces, these particles were not able to infect the mouse or cause paralysis.
“Phase 2 is currently underway and the World Health Organization is planning Phase 3 trials in the hope of accelerating the development of the vaccine as an emergency measure to stop these vaccine related polio outbreaks,” said Raul Andino, who led the work.