Group A Strep infections are caused by bacteria: group A streptococcus (GAS). There are two types of Group A Strep infections: invasive and non-invasive.

• Non-invasive GAS infections are usually mild, and limited to localised areas, such as strep throat or impetigo (which presents as a skin rash). 
• Invasive infections are more serious. In such situations, the bacteria may invade the underlying tissue or get into the bloodstream. This also depends on the age and vulnerable health status of the infected person. Invasive Group A Strep disease can lead to puerperal fever (postpartum infection), septicaemia (blood poisoning), meningitis or necrotising fasciitis.

What are the symptoms of Group A Strep infections?

Most Group A Strep infections are relatively mild illnesses. The symptoms are usually mild and do not last long. Symptoms may vary depending on the type of infection. Most Group A Strep infections are accompanied by fever. The incubation period (the time between exposure and the first symptoms of illness) depends on the type of infection. Scarlet fever has an incubation period of 2 to 7 days, while strep throat is 2 to 4 days.

Invasive Group A Strep infections are often more serious. A person with an invasive GAS infection will usually need to be admitted to hospital. Various severe symptoms may occur:

• Skin infection. Underlying tissues such as muscles or bones may sometimes also be affected, possibly even leading to serious damage to skin and muscle (necrotising fasciitis).
• Deeper infections, such as meningitis, pleuritis, or infections that affect the joints or lungs.
• Puerperal fever (postpartum infection). This is an infection of the uterus after childbirth, sometimes accompanied by sepsis.
• Septicaemia (blood poisoning) leading to low blood pressure and elevated heart rate (septic shock), which may cause organ failure if it persists for too long. Symptoms often include high fever, chills, muscle pain, drowsiness and confusion.

How does a Group A Strep infection happen?

Many people carry the bacteria in the nose and throat or on the skin without any symptoms of disease. Group A streptococci can be transmitted via tiny droplets that are expelled while coughing, sneezing and talking. If other people inhale the droplets, they could become infected. A person carrying the bacteria can also infect others by touching things. Hand contact can transfer the bacteria to toys, utensils, dishes and food.

A person is contagious while carrying the bacteria or until the infection is cured. Once a person has received treatment with antibiotics, they are still contagious for 24 hours after the first dose of medicine.

How common are Group A Strep infections in the Netherlands?

Group A Strep infections are very common in the Netherlands. There are seasonal variations in the types of disease caused by the infections. Strep throat mainly occurs in winter, while skin infections like impetigo are more common in summer.

Some severe infections are subject to a mandatory notification. That means doctors and laboratories must report the infection to the Municipal Public Health Services (GGDs). This involves puerperal fever (postpartum infection), streptococcal toxic shock syndrome or severe subcutaneous infections (necrotising fasciitis).

Since spring 2022, reports of invasive Group A Strep infections have been increasing, after low numbers in 2020 and 2021. The increase has mainly been observed among children aged 0-5 years.