This Virus Has Resurfaced!

On July 18, a case of polio was discovered in Rockland County, New York, the first case in the United States in nearly a decade. A statement from the New York State Department of Health said the case was of an adult who developed bilateral lower extremity paralysis rapidly after two days of low fever, neck stiffness, back pain? and abdominal pain, and who had not been vaccinated against polio and had no recent history of travel abroad. Immediately afterwards, poliovirus was detected in sewage in several counties in upstate New York. In this day and age of infectious disease, this was a real shock.

Poliovirus is transmitted primarily from person to person or through contaminated water. Infection with poliovirus results in flu-like symptoms in about 25% of patients, meningitis in 1-5%, and paralysis in 0.05-0.5% due to viral infection of the spinal cord. Although the vast majority of people who become infected have no symptoms, they can still transmit the virus. Studies have found that if one case of paralysis due to polio infection is found, it is likely that there are at least 100 people in the community with asymptomatic poliovirus infection. This is what worries the CDC, and this one case of polio reported in New York may be just the tip of the iceberg.

Although polio is an incurable disease, infection can be prevented by vaccination, and in 1979, polio was declared eradicated in the United States, meaning that the virus is no longer routinely transmitted in the country. According to the Centers for Disease Control and Prevention's childhood vaccination data, approximately 92.7% of 2-year-old children are vaccinated against polio. And the percentage of children under two years of age in Rockland County, N.Y., who received three doses of polio vaccine dropped from 67.0% in July 2020 to 60.3% in August 2022 (and in some regions, only 37.3% ). This case of polio was seen in that area where vaccination rates are low.

Oral polio vaccine (OPV) and inactivated polio vaccine (IPV) are the two primary polio vaccine kinds used globally.

The inactivated IPV vaccine was developed by Jonas Edward Salk in 1952 and is biologically inactive because the poliovirus is killed, but can still trigger an immune response in the recipient; the live attenuated OPV vaccine was developed by Albert Sabin, and uses a biologically active attenuated strain of the poliovirus.

In contrast to IPV vaccine, OPV is preferred by less developed third-world countries due to the ease of administration (oral) and the cheap production cost, as well as having a good immune effect (live vaccine virus multiplies in the human body to stimulate the body to develop immunity).

The development of medically acquired poliovirus is a possibility, nonetheless, given that OPV is a live virus. It is possible that the attenuated virus contained in the oral OPV vaccine may revert to a pathogenic virus called vaccine-derived poliovirus (VDPV), which means that an estimated average of 1 in 750,000 vaccine recipients develops vaccine-associated paralytic poliomyelitis (VAPP). There is presently no attenuated OPV vaccine available in the United States; only the IPV vaccination is.

This time it was the vaccine-derived poliovirus type 2 that was found in New York.

The New York City Health Department is asking all unvaccinated or partially vaccinated people to get immunized right now in order to stop the spread of the poliovirus.