Exploring a paralytic poliomyelitis case in an unvaccinated person

By Bhavana KunkalikarAug 19 2022Reviewed by Aimee Molineux

In a recent study published in the Morbidity and Mortality Weekly Report, researchers investigated the public health response to a paralytic poliomyelitis case in an unvaccinated person.

On 18 July 2022, the New York State Department of Health (NYSDOH) reported the identification of poliovirus type 2 in stool samples collected from an unvaccinated immunocompetent young individual residing in Rockland county, New York, who displayed acute flaccid weakness. The patient reported symptoms of fever, gastrointestinal issues, neck stiffness, and limb weakness. The patient was subsequently admitted to a hospital with possible acute flaccid myelitis (AFM). However, laboratory results detected vaccine-derived poliovirus type 2 (VDPV2) in the stool samples collected 11 and 12 days after symptom onset. To date, Sabin-like type 2 polioviruses were detected in the patient’s resident county up to 25 days before and 41 days after the date of symptom onset in the patient.   

Case findings

In June 2022, a young individual who was unvaccinated against polio presented a five-day history of fever, back and abdominal pain, neck stiffness, constipation, and two days of weakness in bilateral lower extremities. The patient visited an emergency department and was admitted to the hospital with suspected AFM. The patient was subsequently shifted to a rehabilitation facility approximately 16 days after the initial onset of symptoms with ongoing flaccid weakness in the lower extremities.

Nasopharyngeal or oropharyngeal swabs and cerebrospinal fluid samples collected from the patient tested reverse transcription–polymerase chain reaction (RT-PCR) negative for human parechovirus, enteroviruses, as well as common respiratory pathogens, and encephalitis viruses. Additionally, sequencing and RT-PCR of the stool samples performed by the NYSDOH laboratory detected poliovirus type 2. Specimens tested at the Centers for Disease Control and Prevention (CDC) further confirmed the presence of poliovirus type 2. Further sequencing also identified the virus as VDVP2, which differed from the Sabin 2 vaccine strain, which suggested that viral transmission had occurred for up to one year; however, the location of the transmission is not known.

Public health response

NYSDOH, CDC, and local health authorities investigated and responded to the notification of the VDVP2-positive specimen on 18 July 2022. An NYSDOH advisory was issued on 22 July 2022 to increase awareness of healthcare providers and to improve the detection of potentially infected individuals. Wastewater from Rockland and other New York counties was tested to assess vaccination coverage in the patient’s local community. The authorities also supplied inactivated polio vaccine (IPV) to the appropriate immunization providers and launched vaccination clinics across Rockland county.

Enhanced surveillance was conducted for persons under investigation (PUIs) who met the clinical criteria and resided in or traveled to certain counties, neighborhoods in New York, or other countries since 1 May 2022. By 10 August 2022, three additional individuals were categorized as PUIs. However, specimens provided by the PUIs yielded poliovirus negative results.

Furthermore, by 10 August 2022, 260 wastewater samples were collected from treatment plants in Orange and Rockland counties and tested for poliovirus. Out of these, 8% tested RT-PCR positive for poliovirus, including 13 and eight samples from Rockland and Orange counties, respectively. Notably, 20 wastewater samples obtained from May to July were linked genetically to the virus from the patient’s stool specimen. Moreover, one additional sample was detected in April from Orange county that had poliovirus type 2.

The authorities also launched additional public and clinic health surveillance activities to detect the presence of symptomatic nonparalytic infection or more severe symptoms along with asymptomatic infections in counties having poliovirus-positive wastewater findings. The Rockland County Department of Health also launched a countywide vaccination program on 22 July 2022.

The present study highlighted the risk involved in contracting paralytic disease among unvaccinated individuals. The researchers believe that citizens should stay updated with the recommended IPV vaccination schedule to combat the virus.