There are two kinds of vaccines against polio. One, given via injection, uses an inactivated virus and is known as IPV. The other is an oral vaccine, using a weakened but not fully inactivated strain, and is known as OPV. OPV, the original polio vaccine you might remember getting if you’re of a certain age, was widely used in America for decades. It is cheap, easy for anyone to administer, and provides strong protection against the virus. However, since it was not inactivated, it could cause paralytic polio in some recipients and was not safe to administer to the immune-compromised nor their close contacts. Due to these problems, America, like most Western nations, transitioned to the safer, inactivated IPV vaccine injection decades ago.

As our overworked fact-checkers are learning to their unease, it turns out there’s another big problem with the OPV vaccine: vaccine-derived polioviruses. When immunodeficient people are exposed to the weakened OPV version of the disease, the virus can stay in their gut for years, slowly mutating into new strands, which can then emerge and spread to infect others.

The good news? If your children have been vaccinated against polio with IPV, they are safe from any scary polio symptoms even when the oral-vaccine-derived variants show up in your town. A frightening reemergence of polio is unlikely in America as long as traditional childhood vaccination rates hold steady. On the other hand, considering that we are facing a catastrophic loss of trust in the public health community due to a long train of abuses, such as the scary push to inflict unnecessary experimental vaccines on children, we may not be able to count on those traditional vaccination rates holding up for long.