Confirmed case of polio in the United States signals need to increase vaccination rates

In the Midwest United States (US) in the early 1950s, two of my uncles contracted poliomyelitis ("polio"). One recovered uneventfully; the other required months of respiratory support with an iron lung. Thanks to vaccination against poliovirus, those of us born in the US since 1955 mostly have known only of polio through family stories like these. News of a confirmed polio case in New York (NY) state earlier this summer, however, has brought polio back into our awareness. 

According to the US Centers for Disease Control and Prevention (CDC), most cases of poliovirus infection are asymptomatic. Approximately 25% of infected persons will experience flu-like symptoms, 1-5% will have meningitis, and between between 1 out of 200 persons to 1 out of 2000 persons will experience paralysis of limbs and, potentially, the muscles that control breathing. The CDC notes that only persons with paralytic disease, by definition, have poliomyelitis (or "polio"). Poliovirus "lives in an infected person's throat and intestines," and infected persons can shed the virus for weeks. The New York State Department of Health launched a poliovirus wastewater surveillance program after this individual's diagnosis was confirmed, which has since detected poliovirus in 4 counties in and around where the diagnosed individual lives. 

In the US, only inactivated polio vaccine (IPV) is administered, but many other countries rely on oral polio vaccine (OPV). OPV is attentuated but live, and unvaccinated persons can contract this attenuated virus:

VDPVs [vaccine-derived poliovirus] can emerge when live, attenuated OPV is administered in a community with low vaccination coverage. Replication of OPV in a person who was recently vaccinated can result in viral reversion to neurovirulence, which can cause paralytic poliomyelitis in unvaccinated persons who are exposed to the vaccine-derived virus.

The individual in NY state with polio had "[v]accine-derived poliovirus type 2 (VDPV2) ...detected in stool specimens obtained on days 11 and 12 after initial symptom onset." Since OPVs haven't been administered in the US since 2000, this individual would presumably have caught poliovirus from an individual vaccinated outside of the US; "[e]pidemiologic investigation [has] revealed that the patient attended a large gathering 8 days before symptom onset and had not traveled internationally during the presumed exposure period." 

The wastewater reports indicate that VDVP2 has spread through this four-county area in the southeast corner of the state. Vaccination levels in the diagnosed individual's county are relatively low, with "3-dose polio vaccination coverage among infants and children aged <24 months living in Rockland County [at] 67.0% in July 2020 [which] declined to 60.3% by August 2022, with zip code–specific coverage as low as 37.3%." The NY State Department of Health has been working with local physicians and health care systems to increase IPV vaccination.

The COVID-19 pandemic has resulted in delayed and missed preventive care for countless persons, including a marked decrease in routine vaccination administrations. The reemergence of polio in NY state should prompt all of us to reassess our patients' vaccination status and engage in targeted, deliberate efforts to increase vaccinations. Office reminder and recall interventions can increase vaccination rates, as can physician face-to-face counseling with parents. This 2016 AFP article on "Strategies for Addressing and Overcoming Vaccine Hesitancy" has many useful tips, and a new online guide developed by Canadian researchers to address COVID-19 vaccine hesitancy, which was recently described in the Annals of Family Medicine, also contains useful strategies.