Portal:Viruses/Selected miscellany/15

A global drive to eradicate poliovirus started in 1988, when there were an estimated 350,000 cases of wild poliovirus infection globally. Two diseases, both caused by viruses, have been eradicated, smallpox in 1980 and rinderpest in 2011. Poliovirus only infects humans. It persists in the environment for a few weeks at room temperature and a few months at 0–8 °C. The oral polio vaccine is inexpensive, highly effective and is predicted to generate lifelong immunity. Reversion of live vaccine strains to virulence has resulted in occasional cases of vaccine-associated polio paralysis.

Two of the three strains of wild-type poliovirus have been eradicated. Annual reported cases of wild poliovirus infection fell to a low of 22 in 2017, but had risen to 176 in 2019. As of 2020, the wild virus remains endemic only in Afghanistan and Pakistan, but vaccine-derived poliovirus is circulating in several countries. A lack of basic health infrastructure and civil war remain significant obstacles to eradication. Some local communities have opposed immunisation campaigns, and vaccination workers have been murdered in Pakistan and Nigeria.