New York state, London, and greater Jerusalem may have been the starting point for this year's outbreak of the disease. A child in Afghanistan or Pakistan was given two drops of the oral vaccine in December of 2021. The vaccine virus was found in an undervaccinated Orthodox Jewish community in London after the family traveled to the United Kingdom. Along the way, it began to change, changing into a vaccine that can paralyze in rare cases.
Nicholas Grassly, an Epidemiologist at Imperial College London and member of the U.K. National Authority for the Containment of Polioviruses, said that the virus jumped to Israel and an Orthodox Jewish community in Rockland County. The epidemiological timeline and viral sequence detected in sewage were used to reconstruct theplausible scenario. In Rockland County, an unvaccinated man in the Orthodox community sought care for weakness in his legs in June.
Unvaccinated and undervaccinated people are at risk in wealthy economies. New York Governor Kathy Hochul declared a state of emergency in an attempt to contain the outbreak.
Grassly and other experts stress that there is no chance of a big outbreak of the disease in rich countries. There is a chance that we will end up reporting a couple of cases in London. Mark Pallansch believes that the same is true for New York state. Both are more concerned about the outbreak in low-income countries, which has already paralyzed almost 300 children this year, mostly in Yemen and Africa, and about a resurgence of the wild vaccine in Africa.
It is cheap, easy to use and confers robust gut immunity that help stop the spread of the disease. The vaccine virus can be spread from person to person, just like the wild virus, if the immunization rate is low. There are only a few nucleotide changes in the VP1 region that are needed to turn a harmless Sabin virus into a vaccine-derived version of the disease. Wealthy countries use the vaccine because it requires an injection. The vaccine can't be turned back on.
One of the threepoliviruses, type 2, is the cause of most VDPV outbreaks. The component of the vaccine that protects against type 2 has been removed from general use due to the fact that type 2 has been eradicated. Both Afghanistan and Pakistan used type 2 OPV.
The viruses that arrived in New York, London and Israel were only a small part of the journey. Grassly says that a gradual evolution to a VDPV can be seen in the sequence analysis of virus samples collected from wastewater in London. The New York state health authorities found traces of a type 2 Sabin-like virus in the wastewater as early as April. There were 10 changes in the VP1 region of the virus that paralyzed the young man. Some of the viruses found in New York are full-blown VDPVs.
In the U.S. and the UK, vaccine rates are high but low. In Rockland County, where anti-vaccine sentiment is high, less than half of children under the age of 2 have received the full three doses of vaccine. Coverage is only 37% in one zip code. The United States almost lost its Measles-free status due to a huge outbreak of the disease in Rockland. Pallansch says the June case istragic but preventable.
The state has launched a campaign to make sure children are up to date on their immunizations. The U.K. and U.S. experts think that IPV can probably stop the outbreak. Andrew Pollard is the director of the Oxford Vaccine Group and chair of the U.K.Joint Committee on Vaccination and Immunisation. There is a chance that it will work. It's over.
The most resistant communities have had limited success with the vaccine. In pockets where vaccine coverage is low, the virus may burn itself out because the susceptible population won't be large enough to sustain spread.
In wealthy countries, the kind of Sanitation issues that we see in poor countries don't exist. The disease thrives in places with little or no access to clean water and proper sanitary practices. Respiratory is the primary route of transmission in high income countries.
Contingency planning is underway in both the U.S. and the U.K. to evaluate a new vaccine designed to be just as effective at stopping an outbreak as O. In low-income countries, the vaccine is being used to fight the spread of the disease. To use nOPV2 in the U.S. and U.K., they would have to go through a lot of hoops. Janell Routh is leading the investigation into the New York case.
There are other threats to the eradication effort. Pakistan has already reported 17 cases this year which is up from one in all of the previous year. After being confined for years to Afghanistan and Pakistan, the wild virus jumped to Africa in 2021, where it hasn't been seen in five years. Six children have been paralyzed in two African countries. There is a high chance of further spread. There is an outbreak of vaccine-derived strains in the country.
New York state and London are dealing with the effects of the disease, while the global priority is to stop it at the source. He says that they are doing everything right at the moment.
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