What Are the Differences Between the Attenuated and Inactivated Japanese Encephalitis Vaccines?

The attenuated Japanese encephalitis (JE) vaccine is a live vaccine. Its main advantages include a reduced number of doses—only two doses are required—and a relatively small dose volume, yet it provides relatively long-lasting immunity. However, this vaccine has certain drawbacks: there is a risk of reversion to virulence, and it is comparatively more difficult to store. In contrast, the inactivated JE vaccine is a killed vaccine. Its advantages include no risk of reversion to virulence, relatively high safety, and easier storage. However, it requires four doses, each administered in a larger volume, and confers protection for only 3–5 years, necessitating repeated vaccinations.