The poliovirus was supposed to be gone by now—by 2000, in fact—assigned to the dustbin of history, like smallpox, the only human pathogen ever eradicated. But the poliovirus did not cooperate, for reasons both social and scientific. Since 1988, global polio cases have dropped more than 99%, but the virus is hanging on in some of the most troubled corners of the world, like Nigeria and Pakistan, where poverty and violence make it hard to vaccinate all the kids. Now, a new study in Science and a related report published online on 11 July in The Lancet suggest that an old vaccine, used in a new way, may help break the impasse. Jonas Salk's inactivated polio vaccine (IPV) has been widely used in wealthy countries, but it was sidelined in the global polio eradication initiative because of its cost and the challenge of delivering an injectable vaccine. The new studies show that, in children who have already received multiple doses of the oral polio vaccine (OPV), adding a shot of IPV is better at boosting immunity than another dose of OPV alone. And that suggests an expanded role for IPV in the global polio program, not just in routine immunization but in mass vaccination campaigns to accelerate eradication of the virus. IPV is still expensive and difficult to use, and OPV remains the vaccine of choice in the eradication program. But in some of the most challenging settings, where the virus in entrenched and conflict limits access to children, the new work suggests that using IPV and OPV together may be just what is needed to finish the job.