The development of upgraded vaccines against all three types of polio by US and UK teams is a significant step towards eradicating the disease. These vaccines contain weakened live polio viruses that have been genetically redesigned to remain in their weakened state. Polio cases have decreased by over 99% since the late 1980s, thanks to vaccination efforts.
However, the challenge lies in ensuring that every child receives these improved vaccines to effectively stop the spread of the disease. Polio can lead to paralysis when it reaches the nervous system. The wild poliovirus is now limited to small areas in Afghanistan and Pakistan, with oral vaccines playing a crucial role in eradication efforts.
One issue with oral vaccines is their genetic instability. A single mutation can reverse the weakened state, allowing the virus to leave the child’s stomach, invade the nervous system, and cause paralysis. Moreover, if these mutated viruses are excreted in the child’s feces, they can infect unvaccinated individuals and trigger outbreaks.
In recent years, cases of “vaccine-derived polio” have outnumbered those of the wild poliovirus. A polio strain detected in London’s sewers was linked to the oral vaccine. This highlights the need for continued research and efforts to improve vaccine stability and ensure widespread vaccination coverage to eliminate polio globally.