Examples of live attenuated vaccines

A live attenuated vaccine contains a living virus or bacterium that has been weakened so it can stimulate immune memory without causing the usual illness in most people. Because the immune response can resemble a natural infection, protection may be strong and long-lasting. These vaccines are different from inactivated vaccines, which contain germs that cannot reproduce.

Examples include measles, mumps and rubella vaccination, chickenpox vaccination, and yellow fever vaccination. The right choice depends on age, health, previous doses and travel plans.

Tell the vaccinator about pregnancy, medicines that suppress immunity, serious allergies and any previous vaccine reaction. Keep your vaccination record available so the schedule can be checked. Mild soreness, tiredness or a low fever can occur after some vaccines; follow the aftercare advice given at the appointment.

Seek urgent medical help for trouble breathing, swelling of the face or throat, collapse, or a rapidly spreading severe reaction after vaccination. Contact a clinician promptly for a persistent high fever, unusual weakness or symptoms that concern you. A clinician can also advise whether a live vaccine should be delayed or avoided because of a health condition.

Ask which vaccine is recommended, whether you need a further dose, how pregnancy or immune problems affect the decision, and which symptoms should prompt a call.