When the World Health Organization confirmed in June 2025 that the spread of the poliovirus remained a Public Health Emergency of International Concern, it identified several countries where visitors are at risk of contracting this severe disease.
As of August 27, 2025, new data from the Global Polio Eradication Initiative (GPEI) reveal an unexpected surge in polio cases in the Republic of Yemen, situated in southern Arabia.
According to the GPEI, 25 circulating vaccine-derived poliovirus type 2 (CVDPV2) cases were reported this week. This updated data brings the number of cases in Yemen for 2024 to 187 and 29 for 2025.
‘The recent increase in reported cases and environmental sample isolates from 2024 and 2025 is not particularly linked to an increase in poliovirus transmission, but rather to retrospective testing,’ wrote the GPEI.
CVDPV2 is a strain of poliovirus that can emerge in under-vaccinated populations when the oral polio vaccine (OPV) strains genetically revert to a form that can cause paralysis.
To address the shortcomings of this vaccine, the nOPV2 vaccine has been deployed over 1 billion times in various countries.
In the United States, the inactivated polio vaccine (IPV) was developed in 1955 and has been offered since 2000. IPVs produce antibodies in the blood that target all three types of poliovirus, thereby preventing the virus from spreading.
As of September 2, 2025, the U.S. CDC recommends IPV booster doses for specific travelers visiting areas where poliovirus has been detected, such as Israel and Germany.
IPVs are currently offered at travel clinics and pharmacies in the U.S.