What is the latest recommended time to administer the Japanese encephalitis live attenuated vaccine?

The attenuated live Japanese encephalitis (JE) vaccine effectively stimulates the body to produce antibodies, offering excellent immunogenicity and long-lasting protection. So, what is the latest recommended age for administering the JE attenuated live vaccine?

What Is the Latest Recommended Age for Administering the JE Attenuated Live Vaccine?

The JE attenuated live vaccine is included in China’s national immunization program. Its primary purpose is early prevention of Japanese encephalitis—a viral infection-induced encephalitis. This vaccine effectively stimulates antibody production, confers robust immunity, and provides prolonged protection. Typically, two doses are required, with an interval of one year between doses recommended to minimize potential adverse effects in children. The vaccine is generally administered to infants aged eight months or older—commonly around one year of age.

As a live attenuated vaccine, the JE vaccine induces protective antibodies following administration. Upon subsequent exposure to the JE virus, vaccinated individuals are protected from infection and subsequent development of Japanese encephalitis, provided the standard immunization schedule is followed. After vaccination, infants may experience mild side effects such as fever, which typically resolve spontaneously within two days. The standard dose is 0.5 mL: the first dose is administered at eight months of age, and the second dose at two years of age. While administration after age two is permissible, delays beyond the recommended schedule should be avoided.

However, eligible children should receive the vaccine according to local epidemiological conditions or as mandated by local government health authorities. Wishing you good health and happiness!