The multibillion-dollar global effort to eradicate polio hasn’t just stalled, it’s moving backward. Cases are on the rise and expected to climb even further in the coming months. The pandemic is part of the problem. In March, WHO ordered a pause to all polio eradication campaigns to make sure vaccinators going door to door weren’t unwittingly contributing to the spread of COVID-19. “As a result, 30 to 40 countries have not conducted mass immunization campaigns,” says Michael Zaffran, head of the Global Polio Eradication Initiative at the World Health Organization. “During that period, up to 80 million children have been left unprotected against polio.” The fear is that with so many children now susceptible to polio, outbreaks could erupt.