Japanese encephalitis vaccine out of stock: advice for travellers and health professionals

Important advice on Japanese encephalitis vaccine shortage for health professionals

• This updates the news item of 10 January 2024

Japanese encephalitis is a vaccine-preventable viral disease spread to humans from animals and birds via the bite of an infected Culex spp. mosquito, which mostly feed between dusk and dawn. These mosquitoes are mainly found in rural areas but are also found in urban locations.

The risk of Japanese encephalitis for most travellers to Asia is very low, especially for short-term travellers visiting urban areas, estimated to be less than one case per million travellers [1].

Most cases of Japanese encephalitis are asymptomatic (without symptoms) or present with non-specific flu-like symptoms; rarely more serious symptoms can occur [2].

The risk of acquiring Japanese encephalitis can be reduced by insect bite avoidance methods. Following careful risk assessment, Japanese encephalitis vaccine may be recommended to certain groups of travellers.

Japanese encephalitis vaccine is currently out of stock, although some clinics may have vaccine available.

Advice for travellers

Before you travel

If you are planning to visit countries where Japanese encephalitis vaccination is recommended for some travellers, get travel health advice from your GP, practice nurse or a travel clinic, ideally at least four to six weeks before you travel. You can find information about disease risks on our Country Information pages.

It is possible that Japanese encephalitis vaccine may not be available from some travel health providers due to a vaccine supply issue, If you are at risk from Japanese encephalitis infection, you should still seek advice about possible alternative sources of vaccine and about other important prevention measures.

While you are away

The mosquito that spreads Japanese encephalitis mainly bites from dusk to dawn. Reduce your risk by wearing long sleeves/ trousers, applying insect repellent regularly and follow insect and tick bite avoidance advice.

Advice for health professionals

Where Japanese encephalitis vaccine is in short supply or out of stock, health professionals may need to:

• prioritise vaccine doses and schedules for those at highest risk, such as travellers who intend to live or travel for long periods of time in Japanese encephalitis risk areas or during outbreaks and those doing activities where there is significant rural, outdoor or night time exposure e.g. fieldwork, camping or cycling [3].
• delay vaccination for a few days until vaccine is back in stock (there is no need to restart the course). Information on interrupted vaccination schedules is available.
• consider if the traveller can start or complete their course when abroad. The ISTM Global Travel Clinic Directory provides details of clinics at travel destinations, if courses need to be started or completed abroad.

Information about vaccine supplies should be sought from Valneva.