Given that polio had been completely eradicated on this region of the world, how could a ten-month-old baby in Gaza contract it?
The poliovirus sequences detected in Gaza in July 2024 suggest that these viruses could also be related to a strain circulating in Egypt, a virus possibly introduced into Gaza as early as September 2023.
This might be on account of the character of the oral poliovirus vaccine (OPV), which accommodates a weakened live poliovirus that could be shed by vaccinated individuals. This suggests that the virus can have been introduced by someone traveling to the region.
The war in Gaza has also provided a really perfect environment for the virus to thrive and spread, on account of unsanitary conditions with little access to scrub water and sanitation.
Can a virus “survive” (remain viable) for long periods of time with no human host?
Yes, poliovirus is an incredibly stable virus that may remain infectious outside the human body for long periods of time, depending on environmental conditions. For example, polioviruses are able to surviving in groundwater for several weeks.
Can you explain what “wild-type” poliovirus is, versus “variants” obtained from the vaccine?
Wild-type poliovirus is a virus that naturally circulates within the environment, while the vaccine strain is said to the weakened virus in OPV, which is able to causing paralysis in very rare cases. is
Is the wild type still endemic anywhere on the planet?
Due to the success of the Global Polio Eradication Initiative led by the World Health Organization in 1988, type 2 and sort 3 polioviruses have been eradicated. Only type 1 poliovirus is currently circulating in Afghanistan and Pakistan where it exists. 27 cases have been recorded so far in 2024..
EPA/Qudratullah Rizwan
Why are most polio vaccine cases different?
Due to the success of the Global Polio Eradication Initiative, nearly all of cases of paralytic polio at the moment are vaccine-preventable. OPV has been instrumental within the near eradication of untamed poliovirus worldwide. However, in areas where vaccination rates are low and lots of individuals are at risk of infection, a weakened virus can replicate. Unfortunately, each round of replication increases the virus's ability to revert to a form that causes disease and paralysis.
Why was the old oral polio vaccine discontinued in 2016?
After the eradication of type 2 poliovirus in 1999, only cases of type 2 paralytic polio received the vaccine. Therefore, to forestall these cases, it was decided to change from the unique trivalent OPV, which accommodates all three serotypes of poliovirus, to a bivalent OPV vaccine, which accommodates only type 1 and sort 3 poliovirus. There were tensions. An additional type 2-specific monovalent vaccine is obtainable with any vaccine-derived type 2 should the situation arise.
Was it a mistake, as some experts have suggested?
Although this decision was made in good faith, hindsight suggests that the extent of vaccine-derived type 2 poliovirus was underestimated. The Global Polio Eradication Initiative has prepared a report on the choice and the draft report, which is open for public comment, calls the switch to bivalent OPV a “Incompetent Failure”.
What style of poliovirus vaccine is getting used in the present campaign in Gaza?
More than 1.6 million doses of Novel Oral Poliovirus Vaccine Type 2 (nOPV2) – a brand new poliovirus vaccine – will likely be delivered to the Gaza Strip to supply two doses to greater than 640,000 children under the age of ten.
Will it have the identical risks because the old polio virus vaccine? That is, could it enter the wastewater and cause more polio cases?
No, nOPV2 is a next-generation version of the normal type 2 monovalent oral polio vaccine used to answer outbreaks of vaccine-derived type 2 poliovirus. The essential difference is that the brand new vaccine accommodates a weakened virus that has been genetically modified to make it more stable and fewer prone to revert to a more virulent form that may cause paralysis, thus Increases the possibilities of effectively stopping outbreaks.
What other diseases are prone to spread in Gaza given the disruption of the vaccination campaign?
Other vaccine-preventable diseases comparable to measles, pneumonia and diarrheal diseases, comparable to rotavirus, all have the potential to emerge. Each with its own risks and complications, so it's really vital that as many vaccines as possible are delivered to Gaza.