Officials in New York are sounding the alarm about an outbreak of polio which has paralyzed one person. Since most cases are asymptomatic and paralysis only occurs in about 1 of 200 people, health experts warn this means hundreds are infected.
The US was declared polio-free in 1979 following extensive vaccination efforts. However, the disease has been reappearing and organizations like the Pan American Health Organization are warning that we could face a dangerous re-emergence. This marks the first case of the disease in the US in over a decade.
Current Situation
The accepted vaccination rate to prevent re-emergence of polio is 95%. In New York, the vaccination rate for polio is 79%. In Rockland County, where the paralysis case was reported, the vaccination rate is only 61%. The patient paralyzed was unvaccinated, and even without herd immunity vaccination still protects individuals against infection and paralysis.
Wastewater testing has also discovered the virus in other New York localities and Governor Kathy Hochul declared a disaster to bolster vaccination resources. The declaration allows midwives, pharmacists, and emergency medical service workers to give the vaccine.
Around The World
Recently, the virus has also been discovered in Jerusalem and London. These are the first instances of vaccine-derived polio documented in wealthy countries where the disease was previously eradicated. Even though polio infections have been reduced by 99.9% since 1988, until there is full eradication the world is still at risk.
When a person gets vaccinated using the oral polio vaccine, the weakened virus triggers an immune response. In very rare instances, about 2-4 per 2 million doses, the live virus used in the vaccine can cause an infection. And in even rarer circumstances, the virus can then mutate to spread to other un-vaccinated people.
Because of this risk, countries that do not have active polio have largely switched to the inactive vaccine which does not carry any live virus. However, the oral vaccine is easier to administer and more effective at stopping outbreaks and so is still used in areas with active cases and access issues.
Vaccination for Eradication
At this point only Afghanistan and Pakistan have ongoing wild polio infections, and vaccine derived polio accounts for most infections worldwide. Because of this, some advocate for retiring the oral vaccine. Others argue that because of its effectiveness, use of the oral vaccine should be discontinued only once an area has eradicated the disease. Since vaccine derived polio is only a risk to those who have not been vaccinated the recent outbreaks should highlight the importance of continuing to work toward global eradication by protecting against polio. As long as the virus circulates anywhere, everywhere is at risk, and must continue vaccination efforts.