What is a Vaccine?

A vaccine is a kind of medicine that improves your body's immunity against a particular disease. A vaccine is usually not the 'real' disease - it's a dead, dummy form of the real thing. The vaccine fools your immune system into making protection against the real disease, should you ever encounter it while abroad. This means your immune system will be able to fight off the real disease when you're abroad without your ever knowing you had encountered it.

Most vaccine types come in the form of a small injection into the upper arm (the top of the upper arm where the most muscle is found). The injection shouldn't hurt, as long as it's done really gently, using the smallest possible needle and while the arm is relaxed.

Nowadays, combination vaccine shots are available where it's possible to receive one shot that will cover several diseases at the same time (see table below).

Some vaccine types involve one shot only (see table below) and work within 2 weeks. Vaccine types that involve 2 or more shots take a bit longer to work - typically 4 to 6 weeks.

Several vaccine types (three or four) can be given at the same time.

Will a vaccine produce side-effects? Maybe, but probably not. The most common side-effects occur a day or two later and include: heavy arm, some tenderness at the site of injection, mild flu-like symptoms.