"[T]his month the World Health Organization (WHO) in Geneva, Switzerland, proposed a shift in [polio] vaccination strategy from oral vaccines to injected ones that may have to be administered in clinics," Nature reports, adding, "The change is needed to mop up the last remaining pockets of polio, but experts say that it poses challenges in [rural areas], which have poor access to health care." The oral polio vaccine, developed by Albert Sabin and in widespread use through the Global Polio Eradication Initiative (GPEI), contains three inactivated strains of polio, and while the vaccine is cheap and easy to administer, the inactivated virus can revert to disease-causing forms, the journal notes.