What time period was the polio vaccine licensed?

The Ancient period predates germ theory, virology, and vaccine science by thousands of years - poliovirus was not even identified until the 20th century.

The Salk inactivated polio vaccine was licensed in 1955, placing it firmly in the Modern era of medicine. Developed by Jonas Salk, its licensure marked a turning point in public health and led to the near-eradication of poliomyelitis worldwide.

The Medieval period (approximately 5th to 15th centuries) also predates the scientific methodology and biological understanding required to develop and license viral vaccines.