Polio

People who have had polio should still be vaccinated as there are three main strains.

transmission: droplets, contact with faeces, contaminated food or drink.

administration: intramuscular injection, usually with diphtheria and tetanus.

schedule: part of childhood vaccination schedule; booster if last dose was >10 years ago.

Hepatitis A

transmission: via faeces, poor sanitation, contaminated food or drink.

vaccine: alone or with hepatitis B or typhoid fever.

administration: usually intramuscular injection (deltoid muscle).

schedule: one dose may cover the trip, although a booster ideally 6-12 months later (but up to 3 years later) may provide protection for well beyond the next 10 years.

Hepatitis B

transmission: via blood and body fluids.

vaccine: alone or with hepatitis A.

administration: usually intramuscular injection (deltoid muscle).

schedule: three injections over 4-6 months (can be done more rapidly in exceptional circumstances), and a 5-year booster for those at continuing risk.

Japanese encephalitis

transmission: mosquito bites; pigs and wading birds are the most common reservoirs.

administration: usually intramuscular injection (deltoid muscle).

schedule: two injections 28 days apart, although this can be shortened to one week; a booster 12-24 months after the primary immunisation can give protection of >6 years.1

Tick-borne encephalitis (TBE)

transmission: bite from ticks, generally living in undergrowth; very rarely from consuming unpasteurised milk or dairy products from infected animals (typically goats).

vaccine: doses available for adults and for children (1-15 years).

administration: usually intramuscular injection (deltoid muscle).

schedule: three doses - the second dose 1-3 months after the initial dose (which may be sufficient for the ongoing tick season), and the third dose at 5-12 months. A booster dose three years after the third dose can extend protection for 3-5 years.

precautions: TBE vaccine does not protect against other tick-borne infections such as the bacterial Borrelia infection (Lyme disease).

Rabies

transmission: usually a bite or scratch of an infected animal (especially dogs or monkeys), although it can develop from being licked.

administration: intramuscular injection.

precautions: should not be given to patients with bleeding disorders or who are on anticoagulants, unless potential benefits clearly outweigh the risks.

schedule: three doses over a month on days 0, 7 and 28 (will not achieve immune status if third dose given before day 21). It can also be given post-exposure with immunoglobulin: for people with adequate prophylaxis but exposed to a rabid animal, doses should be given on days 0 and 3 of exposure.

booster: a single dose one year after initial prophylactic course, and further boosters 3-5 yearly.

Yellow Fever

transmission: mosquito bite (usually active in daylight hours, rural and urban areas).

administration: subcutaneous injection (although intramuscular injection may be required to comply with the country's yellow fever certification requirements).

precautions: severe adverse events occur at a rate of about 0.3 to 0.8 cases per 100,000 doses and there is a higher risk of complications in people over 60 years.19

schedule: single dose - this may protect for >10 years, but a country may require a new Yellow Fever Certificate requiring re-vaccination.