Taking part in the study will take up some of your time, such as speaking with the study staff, coming to the laboratory and completing body composition measurements, although we will provide you with a detailed assessment of your progress over the course of the study. Some mild bruising/soreness may occur from taking blood; this will be kept to a minimum as we will only use trained personnel. The walking test may cause some feelings of fatigue. Like any vaccination, there are some possible side effects, the most common of these include soreness, redness, warmth, swelling and hardening at the injection site, and fever (<38.8:C). These reactions occur in less than 1 in 10 vaccines administered. It is possible that, in some very rare cases, a severe allergic reaction may occur; however, this is extremely rare. Additionally, this is a standard, commonly used vaccination which will be carried out by a trained nurse.