Group A streptococci (GAS), also referred to as ‘strep A’, is a common bacterium. Some of us carry strep in our throats and on our skin and it doesn’t always result in illness. However, GAS does cause infections, some mild and some more serious.
Milder infections caused by GAS include scarlet fever, strep throat, impetigo and tonsilitis. While these can be unpleasant, they can be treated with antibiotics.
This blog post explains more about GAS and the infections it can cause, as well as how it is spread and what to look out for when you or your child is unwell.
How is GAS spread?
It is spread by close contact with an infected person and can be passed on through coughs and sneezes, or from a wound.
Some people can have the bacteria present in their body without ever feeling unwell or showing any symptoms of infections and while they can pass it on, the risk of spread is much greater when a person is unwell.
How can I stop infection from spreading?
By washing your hands properly with soap and warm water, using a tissue to catch coughs and sneezes, airing your home well, and keeping away from others when feeling unwell, you will be able to reduce the risk of picking up, or spreading, infections.
Which infections does GAS cause?
GAS causes infections in the skin, soft tissue and respiratory tract. It’s responsible for tonsillitis, pharyngitis, scarlet fever, impetigo and cellulitis among other infections. People of all ages can catch these infections although children are more susceptible to scarlet fever, impetigo and strep throat.
While infections like these can be unpleasant, they rarely become serious. When treated with antibiotics, an unwell person with a mild illness like tonsilitis stops being contagious around 24 hours after starting their medication.
In rare cases, GAS can cause more serious infections. When this happens, it is known as ‘invasive group A strep’ or iGAS. Visit the NHS website for signs and symptoms that a young child needs urgent medical care – this will help you decide whether you should ring 111 or go to A&E.
What is invasive group A strep (iGAS)?
These infections happen when the bacteria invade deeper tissue in the body, either through sores or open wounds or the lungs. While iGAS infections are still uncommon, we’ve seen an increase in cases over recent years.
Which infections does invasive group A strep cause?
Invasive infection can take several forms including joint infections, pneumonia, severe soft-tissue infection such as necrotising fasciitis, bloodstream infection and meningitis. Streptococcal Toxic Shock Syndrome can occur when individuals have these severe infections, a life-threatening condition leading to organ failure. These are some of the most severe but rare forms of invasive group A strep.
Are children with chickenpox more vulnerable to iGAS?
Children who have had chickenpox very recently are more likely to develop serious forms of group A strep infection, although this remains very uncommon. The chickenpox rash can make it easier for group A strep to get into the body, which can lead to invasive infection. If a child has chickenpox – or has had it in the last 2 weeks – parents should remain vigilant for symptoms such as a persistent high fever, cellulitis (skin infection) and arthritis (joint pain and swelling). If you are concerned for any reason, please seek medical assistance immediately.
What is UKHSA’s role in managing iGAS?
We identify and manage outbreaks, provide resources to support local health protection systems to respond to cases, develop guidance for healthcare professionals, provide advice to specific settings, create public information resources, and monitor data and surveillance. You can see weekly laboratory notifications and monthly rates of iGAS cases on our Data Dashboard.
