Vigilance and vaccination are key tools as new evidence of polio comes to light. The recent detection of the vaccine-derived poliovirus type 2 case in New York, USA, and isolates in several environmental samples collected in London, are stark reminders that as long as polio exists anywhere, it is a threat everywhere. It also highlights the importance of vaccination as the only form of protection against polio and other vaccine-preventable diseases and the work that needs to be done in our communities to encourage the uptake of vaccines.