Lay summary
In countries with long-standing high immunisation coverage such as New Zealand, waning immunity is a potential threat to the elimination of measles, with increasing cases of measles infection in young adults despite two doses of measles (Me), mumps (Mu) and rubella (Ru) (MMR) vaccine, with potential transmission to others. Health science students in Dunedin and Auckland are required to have tests for Me, Mu and Ru antibody (Ab) and receive a third MMR dose if any negative results, but we don't know how much Ab is needed for protection or if extra MMR doses help. This project will (1) use gold standard Ab measurements to (2) measure responses to aerosolised MMR inhaled into the lungs as a proxy for protection against real measles infection, and (3) in students with low Ab despite two previous MMR doses, compare responses to MMR given using an aerosol device vs injection into the dermis (intradermal) vs current routine subcutaneous injection.