This viral disease is typically transmitted by the bite of a tick or, in rarer cases, by drinking unpasteurisd milk. The infection may be asymptomatic, or it may cause fever, which evolves, in a second stage, into the typical symptoms of meningitis or meningoencephalitis that may be accompanied by episodes of paralysis.

The disease is endemic in most European (including Italy) and Asian countries. Transmission occurs mainly in wooded or rural areas, and the incidence of the disease is highest in spring-summer, when people are more likely to spend time outdoors. There is no curative treatment, so vaccination is the best tool to protect yourself.

The vaccine consists of 3 doses. The second dose is given 1 to 3 months after the first, the third 5 to 12 months after the second. For subjects between 1 and 60 years of age, the first booster is given 3 years after the first administration and every 5 years thereafter. For individuals over 60 years of age, the booster is administered every 3 years.

Inactivated virus vaccine, adsorbed. It exists in adult (0.5ml) and pediatric (0.25ml) formulations. It is administered intramuscularly and field studies have shown its efficacy to be close to 99%.