What happens during the Japanese encephalitis vaccine
The Japanese encephalitis vaccine is a so-called dead vaccine: it contains inactivated pathogens from the Japanese encephalitis strain SA14-14-2. It has been licensed in Germany since March 31, 2009.
The inactivated viruses cannot make people ill, but they can still stimulate the body to produce specific antibodies. If a “real” infection with Japanese encephalitis viruses occurs later, the body is armed – it can fight the pathogen quickly and specifically.
When does vaccination make sense?
Japanese encephalitis is the most common viral brain infection in the Asian region. It is transmitted by mosquitoes mostly in the vicinity of farms. To date, there is no specific treatment for the often fatal disease. About one third of survivors retain neurological sequelae (paralysis, delusions).
Experts therefore recommend Japanese encephalitis vaccination mainly in the following cases:
- During longer-term stays in an endemic area of the disease (South, Southeast, and East Asia), e.g., in the context of family visits or long-term trips
- In case of repeated short-term travels to an endemic area
- When traveling with increased risk of infection with Japanese encephalitis (e.g., when staying overnight in rural regions of endemic areas) – especially during the main transmission season (i.e., the rainy season and beyond) and regardless of the duration of travel
In addition, anyone planning a trip to an endemic area during the main transmission period should always talk to a doctor beforehand about the possibility of Japanese encephalitis vaccination. In individual cases, the vaccination can also be useful in other cases than those mentioned above. This is especially true for people with an increased risk of contracting Japanese encephalitis. Such an increased risk exists, for example, in:
- Carriers of a cochlear implant (in general: in case of disturbed blood-brain barrier)
- High blood pressure (hypertension)
- Diabetes (diabetes mellitus)
- Immune deficiency
- Chronic kidney disease
- Increased outdoor exposure in the endemic area
In addition, Japanese encephalitis vaccination may be useful for people who have occupational contact with the pathogen (e.g., employees in medical laboratories). If a long-distance traveler desires comprehensive protection, doctors usually also perform Japanese encephalitis vaccination – provided there are no contraindications (acute infection, allergy).
How the Japanese encephalitis vaccine is administered
Currently, a vaccine is available in Germany for the prevention of Japanese encephalitis. It can be administered to children from two months of age, adolescents and adults. Children up to the age of three receive only half the usual vaccine dose.
- In the “normal” (conventional) vaccination schedule, these two vaccine shots are given 28 days apart.
- In the rapid vaccination regimen, the second vaccine dose is given as early as seven days after the first. Follow-up over 12 months has shown that the body produces as many antibodies against the Japanese encephalitis virus as with the normal vaccination schedule. However, the rapid vaccination schedule is only available to adults between the ages of 18 and 65.
Regardless of whether the normal or rapid vaccination schedule is used, the second dose of vaccine should be given at least one week before possible contact with Japanese encephalitis virus. This is because the body needs some time for antibody production.
How long does the effect of the vaccination last?
Japanese encephalitis vaccination: Do side effects occur?
In adults, the most common side effects of Japanese encephalitis vaccination are headache, muscle pain, fatigue, and pain and tenderness at the injection site. This may also become red, itchy, and slightly swollen.
Children most commonly respond to vaccination with fever, diarrhea, flu-like symptoms, irritability, and pain, redness, and tenderness at the injection site.
Other recommendations for Japanese encephalitis vaccination.
Japanese encephalitis vaccination is not recommended for anyone with a known allergy to any of the ingredients or to the manufacturing impurities in the vaccine (such as protamine sulfate, formaldehyde).
Anyone who is hypersensitive or allergic to the first dose of vaccine should not receive the second dose.
There are insufficient data on the use of Japanese encephalitis vaccine in pregnant and lactating women. Vaccination during pregnancy and breastfeeding should therefore be avoided.
Where can I get vaccinated?
Before major trips, such as to Asia, it is best to seek advice from a travel medicine specialist. He or she can inform you about the risk of contracting Japanese encephalitis (and other health hazards) at your destination and, if necessary, give you useful vaccinations such as the Japanese encephalitis vaccine.
He will also inform you of other protective measures you should take to heart for the sake of your health during your trip. In the case of Japanese encephalitis, these include, above all, measures to prevent mosquito bites – the viral pathogens of the disease are transmitted by certain mosquitoes.
Japanese encephalitis vaccination: How much does the vaccination cost?
Sometimes the Japanese encephalitis vaccination is given for occupational reasons, for example because someone’s job requires them to travel to Asia or work in a medical laboratory where Japanese encephalitis viruses are handled. In such cases, the employer usually pays for the Japanese encephalitis vaccination.
