Why was smallpox eradicated?

The eradication of smallpox is primarily attributed to widespread vaccination efforts. In the late 20th century, a global campaign led by the World Health Organization effectively utilized the vaccine, which not only protected individuals but also broke the chain of transmission in the population. The strategy involved a focused approach of vaccinating not just those infected but also surrounding communities, thereby creating herd immunity.

As vaccination rates increased, the number of cases decreased significantly, leading to the absence of the disease in entire regions. This concerted effort to vaccinate against smallpox resulted in the disease being declared eradicated in 1980. The robust and systematic vaccination campaigns were instrumental in ensuring that smallpox could not re-establish itself in the population, making it a unique success story in public health history.

While concepts such as natural immunity, limited population impact, and the absence of known carriers can influence the dynamics of disease spread, they do not explain the specific and direct cause of smallpox eradication as effectively as widespread vaccination does.