Invasive GAS disease occurs when the bacterium gets into parts of the body where it is not usually found, such as the blood, muscle, or lungs or the birth canal after childbirth. These infections are called invasive GAS. Two of the most severe, but rare, forms of invasive GAS disease are necrotising fasciitis and Streptococcal Toxic Shock Syndrome.
Most people who come into contact with GAS remain well and symptom-free, or develop mild throat or skin infections. These infections can be easily treated by your GP. Healthy people can get invasive GAS disease from a relative or a member of their household but it is very rare. Certain groups of people might be more at risk of contracting a more serious infection, for example, people who have recently given birth, or had surgery.