Polio outbreak warrants bolstered vaccination efforts

Photo courtesy of Margaret Suckley via Wikimedia Commons.

The word “polio” evokes certain imagery in the minds of the average American, such as black-and-white photographs of children in iron lungs or on crutches, or perhaps even President Franklin Delano Roosevelt, who was infected by polio and paralyzed from the waist down. Since the late 1800s, the disease has occupied a special spot in the consciousness of Americans, one that has largely faded into a shadow of the past in recent years, thanks to widespread efforts to eradicate the disease using vaccination. 

However, on July 21, 2022, the Rockland County, New York, Department of Health announced that a case of the virus was detected in a resident of the county. The man was unvaccinated and said to have caught the disease from a person who had been vaccinated with the oral version of the polio vaccine—one that is often administered in countries outside of the United States. 

In the 1900s, polio occupied a large space in the national dialogue, in part because of the horrifying effects it could unleash on people, especially children. According to the CDC, the majority of people infected with the virus remain asymptomatic and largely unaffected by the disease, and about a quarter of people infected develop symptoms including sore throat, fever, tiredness, nausea, headache and stomach pain. However, a small percentage of people infected develop serious symptoms, including meningitis (infection of the spinal cord or brain), and paralysis. According to the World Health Organization, about one in 200 infections lead to irreversible paralysis. In extreme cases, about five to ten percent of those who are paralyzed due to polio, die because the muscles used for breathing become incapacitated and can no longer function. This recent resurgence of polio, coupled with declining vaccination rates must not be ignored. Doing so would be a public health failure, and special attention must be given to increasing public health messaging and vaccination efforts. 

As fear-inducing as this disease used to be, it barely registers in the minds of most young people today. This is because of widespread vaccination efforts around the world which have come very close to completely eradicating the disease. There are two kinds of polio vaccines, the inactivated poliovirus vaccine (IPV) and the oral poliovirus vaccine (OPV). The IPV is the vaccination of choice in the United States amid low polio risk and the focus is on prevention of severe disease. According to a study published in the Journal of Infectious Diseases, the OPV is still used in countries where the disease is endemic, including many countries in Africa, Asia and South America, where the health infrastructure may not be well enough equipped to handle routine IPV vaccination. According to Nature, the IPV is more expensive, harder to transport and requires specialized training. Administering the OPV lacks these challenges, and is as easy as a few drops into the mouth of children in rural, hard-to-access communities. Additionally, the OPV provides a more robust immune response through the digestive tract, which is similar to the path that the virus takes in the wild. This is an important part of stopping local transmission of the disease in times of outbreaks, and a study published in Developmental Biology shows evidence that immunity can be passed along to other unvaccinated individuals in the area through contact with fecal matter. 

Although the OPV is largely safe and effective, and has been instrumental in the massive reduction in illness and disease from the virus worldwide, there is a small risk that this vaccine, which is derived from weakened but live samples of the virus, can revert to the actual disease, and in some rare cases (two-four cases per million births), cause paralysis. As with all vaccines, there are small risks associated with taking the vaccine, but the benefits overwhelmingly outweigh the potential risks. 

In the United States, where the IPV has largely remained the preferred method of vaccination, the risk of disease is very small, with three doses of the vaccine providing 99 percent immunity, cited the CDC. This robust immunity, however, falls apart when people refuse to receive vaccinations, as seen in the latest case of the man in Rockland County. 

In order for polio to remain in the shadows of history, Yale medicine states that community vaccination rates must reach about 80 percent to induce effective herd immunity, which protects those who are immunocompromised and unable to receive vaccines for medical reasons. According to the New York State Department of Health, the polio vaccination rate in Rockland County is 60.34 percent, well below this target, which indicates that the protection in place to prevent community spread is insufficient.

Recent data from wastewater samples collected by the Department of Health in Rockland County and Orange County (polio vaccination rate: 58.68 percent), New York, have indeed shown that polio is circulating undetected amongst the population, which is extremely worrying. If the virus circulates enough, it may eventually reach populations who are most susceptible to serious effects, such as infants and young children, who may not have received all of their polio vaccinations. The easiest and least expensive way to prevent such a disaster is for people to get vaccinated and keep up to date on the boosters needed to induce robust immunity against polio.

This phenomenon is not unique to the U.S., either. Although there have been no reported cases of polio in the United Kingdom, according to Science, similar wastewater sampling has also shown community transmission of the disease. Therefore it is no surprise that the U.K. has extremely low polio vaccination rates. According to the Guardian, 11 percent of local communities have vaccination rates surpassing 90 percent, and some have less than 50 percent in teenage communities, which may indicate a larger trend of declining vaccination rates. 

Polio wreaked havoc on the U.S. in the 20th century, but the miraculous development of two highly effective vaccines has all but stopped the disease in its tracks, with the disease remaining endemic in only two countries, Afghanistan and Pakistan, according to the Global Polio Eradication Initiative. However, recent data suggests that the disease may be rearing its ugly head once more. The only way to prevent its transmission and to prevent vulnerable communities is by vaccination, which must be made a priority in the long list of public health goals intended to prevent unnecessary disease, suffering and death amongst innocent people. 

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