Final answer:
Smallpox is the only virus globally eradicated, thanks to a massive vaccination campaign led by the World Health Organization; the last case was in 1977. Today, polio is nearly eradicated, with continued efforts to eliminate it fully.
Step-by-step explanation:
The only virus that has been globally eradicated is smallpox.
This eradication was made possible through an extensive and determined global vaccination effort led by the World Health Organization. The campaign saw great success because smallpox, caused by the Variola viruses, could only be spread among humans, making it feasible to interrupt its transmission entirely. By carrying out vaccinations on a massive scale, smallpox was officially declared eradicated in 1980, with the last case diagnosed in 1977. This achievement stands as a significant milestone in medical history and a testament to the effectiveness of vaccinations.
There are ongoing efforts to eradicate other viral diseases, such as polio. While the global incidence of polio has drastically decreased thanks to vaccines like the Sabin vaccine, the disease is not yet completely eliminated worldwide. Nevertheless, its incidence is now rare in many countries, and polio remains endemic in only a few regions. With continued immunization campaigns, there is hope that polio will join smallpox in being the next globally eradicated disease.