The World Health Assembly decided to eradicate polio worldwide by the year 2000, but the polio emergency declared by New York on Friday has raised questions about whether it was truly eradicated.
New York Gov. Kathy Hochul declared a state of emergency amid evidence that the virus is spreading in communities, as polio was detected in sewage samples from four counties near the city.
The statement came more than a month after an unvaccinated adult contracted polio in Rockland County, north of New York City, and suffered paralysis. It is the first known polio infection in the US in nearly a decade.
Polio is a disease caused by a virus that lives in the human throat and intestinal tract. It is spread from person to person by exposure to infected human feces. The virus often spreads unnoticed because 70% of infected people have no visible symptoms.
One in 100 people infected becomes permanently paralyzed. Among people who experience paralysis, the death rate ranges from 2 to 10 percent. The virus mainly affects children aged three and under, and there is no known cure.
Polio was largely eradicated by vaccination
The first major documented polio outbreak in the US occurred in Rutland County, Vermont in 1894, when 18 deaths and 132 cases of permanent paralysis were reported. However, it was not until 1905 that polio was discovered to be contagious.
In 1916, U.S. health officials announced a polio outbreak centered in Brooklyn, New York, that killed more than 6,000 people and crippled thousands more. In 1952, polio cases rose to a record high, and the worst outbreak focused public awareness on the need for a vaccine.
Polio was largely eradicated in the United States by a vaccine that became available in 1955. The doses provide nearly 100 percent immunity.
Since the World Health Assembly decided to eradicate polio globally, substantial progress has been reported from six World Health Organization (WHO) regions. The number of cases of paralytic polio decreased by 99% from 34,617 in 1988 to 496 in 2001.
There are three strains of wild polio, two of which have been officially certified as globally eradicated. But wild poliomyelitis type 1 still affects some countries. In 2021, 649 cases of paralytic polio were reported worldwide.
According to WHO officials, the best way to prevent polio is to get vaccinated. There are two types of vaccines: an inactivated polio vaccine (IPV) given as an injection in the leg or arm, and an oral polio vaccine (OPV).
Although the vaccine is very effective in preventing the disease, it does not block the transmission of the virus. In rare cases, the virus used in OPV can mutate, become virulent, and spread to others, which is called vaccine-derived poliomyelitis.
However, the WHO said children are at far greater risk of polio than any side effects of the vaccine. It only takes one case to put the public at risk, with people who have never had a polio vaccine most vulnerable to infection.
The polio vaccination rate is alarmingly low in some New York counties, with the rate at 60% in Rockland, 58% in Orange, 62% in Sullivan, and 79% in Nassau, the districts where polio detected, according to New York officials. .
According to health officials, hundreds of people across the state may have contracted the virus and not know it. Friday’s emergency declaration aims to increase vaccination rates from the current state average of 79 percent to more than 90 percent.