For many Americans, especially young adults, poliovirus not only has no relevance to their lives, they may not even be sure what it is or how it affects the body.
But make no mistake, polio—an incurable, extremely contagious, and life-altering disease—is a daily reality for some citizens in three countries: Afghanistan, Pakistan, and Nigeria. In these places, this killer virus still holds sway, even though poliovirus has long been absent from most countries in the world.
Globally, there were 223 cases of polio infection reported to the World Health Organization (WHO) in 2012. When we think of how many people are in the world, this number seems almost insignificant, right? Want to eradicate polio? No problem! With a little money and a few volunteers, we can have that off the to-do list by Christmas, right?
Not so fast. What makes the poliovirus “a virus to watch” is precisely because there are so few cases left. In spite of this tiny number of cases, for years, we have not been able to eradicate it. And because we live in an interconnected global society, we still need to be wise about vaccine-preventable diseases, even those not typically found in our hometown. Measles, a disease eliminated from the United States in 2000, still pops up (222 times in 2011) because it’s “imported” from other countries.
We need to pay attention to poliovirus because it is at the center of grim international news: Efforts to finally get rid of the disease in some of the countries where it continues to exist are putting health workers at risk of death.
There are three types of poliovirus (called p1, p2, and p3). Unfortunately, having immunity to one does nothing to protect you from the other two. The virus is spread through fecal-oral transmission, and sometimes, oral-oral transmission. It typically lives in the pharynx (throat) and the GI tract. A person infected with poliovirus can be contagious for up to ten days before experiencing symptoms, and can shed the virus through feces for up to six weeks after symptoms. For a virus this infectious, that’s no good. What is good, however, is that humans (and no animals) are believed to be the only long-term hosts for polio. If we can stop transmission in people, we should be able to eradicate polio once and for all.
Most people infected with poliovirus won’t experience any signs. However, about four to eight percent will have mild symptoms: fever, stiffness in neck and back, flu-like symptoms, and nausea. These symptoms often simply disappear—no big deal. Less than one percent of those infected are not so lucky; these people experience permanent paralysis in their limbs. A small percentage of the paralyzed die because paralysis reaches the respiratory muscles and they cannot breathe (cue memories of the iron lung—an icon of the polio era—a coffin-like structure that uses changes in air pressure to help paralyzed people breathe).
As we’ve said, there’s no cure for polio, only a vaccine. In 1955, Jonas Salk announced the world’s first polio vaccine. Salk’s vaccine was an injectable, killed poliovirus. A few years later, Albert Sabin introduced an oral vaccine, made from an attenuated (a live but weakened, or less virulent) virus. (You can find immunization schedules for both children and adults at the Centers for Disease Control.)
Ironically, it’s not only the infected who suffer: Today, those working to prevent polio infection are targeted. In Nigeria’s Kano state at least nine health workers were gunned down in early February 2013 because they were working on an immunization drive. In December 2012, five Pakistani women and two men were killed in multiple shootings in Karachi because they were working on polio immunization.
Some suggest that this violence is a backlash against previous failed vaccination campaigns. Murder as retaliation for failed vaccines? Extreme, to be sure. But, as always, there is more to consider. Trust is a necessary component to all successful public health campaigns. If people don’t trust public health officials, they may reject the health intervention, which, depending on the intervention, could have disastrous impacts on the health of the community.
In 1996, drug company Pfizer eroded Nigeria’s trust in U.S. vaccines by conducting a vaccine trial that may not have met ethical standards. As a result, children died. Pfizer was sued, and in 2011, it compensated the parents of the deceased children. Granted, vaccine uptake rates in some areas of Nigeria were already low, and there has been a long-standing distrust of widespread vaccination campaigns in the country, in part because of a mistaken belief that they are connected to population and fertility regulation.
However, Pfizer’s actions left an indelible impact on the country. In 2003, political and religious leaders of northern Nigerian states called on parents to boycott polio immunizations because of the possibility that these vaccines could be contaminated with harmful substances (anti-fertility drugs, HIV, etc.). As a result of the nearly year-long boycott, 1,500 children were left paralyzed by a poliovirus genetically linked to Nigeria.
In 2011, it was revealed that the CIA used a hepatitis B vaccination campaign in Pakistan to collect DNA from suspected Bin Laden family members. As a result, the Taliban spread word that U.S. vaccination campaigns were not to be trusted. In July 2011, Pakistani media reported that over 16,000 children were denied vaccinations by parents distrustful of the campaigns.
On the heels of the world’s first successful eradication campaign—of smallpox, in 1980— the 1988 World Health Assembly called for the global eradication of polio. Thus, the Global Polio Eradication Initiative (GPEI) was formed. Since the GPEI’s foundation, polio cases have dropped 99 percent. According to the WHO, more than ten million people were spared paralysis; the WHO also estimates that 1.5 million childhood deaths have been prevented by the campaign.
In January 2013, India celebrated two years since a child was paralyzed by polio in India and one year since a polio case had been detected. However, the importance of prevention efforts and vaccination cannot be emphasized enough. But until the three countries where polio still resides are free of the virus, we must continue to be vigilant, or as CDC Director Dr. Tom Frieden stated in December 2011, “a resurgence of polio could paralyze more than 200,000 children worldwide every year.”
What would it take to finally rid the world of polio?
--By Anna Tomasulo