Vaccines 2025

Poliomyelitis (polio), caused by the poliovirus, remains a key target for global eradication as part of international initiatives led by the World Health Organization (WHO), UNICEF, and the Global Polio Eradication Initiative (GPEI). As of 2025, only two endemic regions remain where local transmission of wild poliovirus type 1 (WPV1) is still reported: Pakistan and Afghanistan.
Vaccination programs in these countries primarily rely on the oral live-attenuated poliovirus vaccine (OPV). However, the attenuated virus in the vaccine can undergo genetic changes and regain virulence, potentially causing disease - a phenomenon known as circulating Vaccine-Derived Poliovirus (cVDPV).
Recently, a high and concerning rate of polio vaccine refusal has been reported in Karachi, the largest city in Pakistan. This phenomenon is driven by political tensions, religious beliefs, concerns about side effects, and disinformation campaigns propagated by local groups. Such resistance directly compromises the ability of vaccination teams to achieve sufficient immunization coverage.
The implications of this trend could be severe. In addition to the risk of continued transmission of wild poliovirus (WPV), the use of a live vaccine in a population with low immunization coverage may prove disastrous, as it increases the likelihood of vaccine virus reversion to virulence. A notable example of the consequences of poor professional decisions is the spread of vaccine-derived poliovirus that led to widespread outbreaks in Africa in 2024.