In accordance with World Health Organization recommendations, applicants for ROC (Taiwan) visas must submit proof of having been administered the oral polio vaccine (OPV) or the inactivated polio vaccine (IPV) from four weeks to one year before applying if they have resided in or visited countries or regions at high risk for polio transmission—namely, Afghanistan, Pakistan, Mozambique, the Democratic Republic of the Congo, French Guiana, and Guinea—for four weeks or longer within the past year.