Primary prevention

Vaccines are available for mumps, measles, rubella, varicella zoster virus, and poliovirus (universal immunization); rabies; Japanese encephalitis (in the appropriate geographic and clinical setting); tuberculosis (Bacille Calmette-Guerin); and various bacteria (Pneumococcus and Meningococcus).

Tick-borne encephalitis

Four inactivated vaccines for tick-borne encephalitis (TBE) have been tested in clinical trials and shown to be safe and effective: FSME-Immun® (TicoVac®) and Encepur® are licensed in many European countries, and TBE-Moscow® and EnceVir® are licensed in Russia and some neighboring countries.[40] Where the disease is highly endemic, the World Health Organization recommends that vaccination be offered to all age groups, including children.[41]​​

The Food and Drug Administration approved TicoVac® in August 2021 to prevent TBE in people ages 1 year and older.[42]​ The Advisory Committee on Immunization Practices (ACIP) recommends TBE vaccination in people who are moving or traveling to an endemic area, and are likely have a high level of exposure to ticks. Vaccination may be considered when the risk of exposure is lower, based on individual factors including medical history and risk tolerance.[43]

Japanese encephalitis

Four types of vaccines for Japanese encephalitis (JE) exist. Most vaccines are cell-culture based. In the US only one vaccine is available, the Vero cell-derived, inactivated, and alum-adjuvanted Japanese encephalitis vaccine based on SA-14-14-2 strain (JE-VC).[44]​ This is also available in Australia and various European countries. Two different Vero cell-derived inactivated vaccines are available in Japan. Both of these are based on the Beijing-1 strain. A live attenuated vaccine also based on the SA 14-14-2 strain is commonly used in China and other East Asian and Southeast Asian countries. Lastly, a live, attenuated, Japanese encephalitis-yellow fever chimeric vaccine is now available in Australia and Thailand. Different vaccines have different recommended schedules based on seroconversion rates and individual studies for specific vaccines. For some of the newer vaccines, booster schedules may not have been determined yet.

Most travelers to JE-endemic countries are at very low risk of the disease, but some will be at increased risk depending on factors such as longer periods of travel, transmission season, and spending time in rural areas.[44] Vaccination is recommended for travelers to JE-endemic countries who plan to spend one month or longer in an endemic area or are frequent travelers to the areas. Vaccination should also be considered for travelers to an endemic area during the transmission season with a shorter than one-month stay if they plan to visit nonurban areas and their activities may increase the risk of disease transmission (e.g., spending substantial time outdoors, especially during the night, or staying in accommodation lacking screens, bed nets, or air-conditioning) or if they visit an area with an ongoing outbreak. Vaccination should also be considered for travelers to endemic areas who are uncertain of specific duration of travel, destinations, or activities.[44]

Vaccination of people living in endemic areas is also recommended.

Meningococcal vaccination

Many developed countries offer routine childhood vaccination for the prevention of meningococcal disease. For full details of US immunization schedules, including indications for booster doses, the ACIP guidelines should be consulted.

CDC: immunization schedules Opens in new window

Pneumococcal vaccination

Rates of pneumococcal meningitis have decreased among children and adults since the pneumococcal conjugate vaccine (PCV7, subsequently PCV13) vaccine was introduced. Although the overall effect of the vaccine is substantial, increases in meningitis caused by nonvaccine serotypes, including strains nonsusceptible to antibiotics, remain a concern.[45][46]

Influenza vaccination

Annual seasonal influenza vaccination can also be recommended to reduce potential extrapulmonary complications including encephalitis.

Secondary prevention

Certain measures are available for the prevention of a limited number of agents (viral and bacterial) that can cause encephalitis.

  • Specific drugs: isoniazid for purified protein derivative positivity in tuberculosis and for post-exposure prophylaxis.

  • Education and avoidance of risk-taking behavior (unprotected sexual acts): prevention of HIV, syphilis.

  • Environmental control (sanitation, vector control and avoidance): Nipah and Hendra virus, all the arboviruses, enteroviruses, typhoid.

  • Isolation should be considered for patients who are severely immunosuppressed and those with rabies encephalitis, exanthematous encephalitis, or contagious viral hemorrhagic fever.[99]

  • As West Nile virus encephalitis has been reported to occur after blood transfusion and solid organ transplantation, sensitive screening laboratory tests are in development, which may guide future preventive measures.[154][155]

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