Invasive strep A: bad in affluent countries, far worse in low-income nations

The deaths of nearly 30 children under the age of 15 years from invasive strep A infections in the United Kingdom between September 2022 and January 2023, together with a rise in new invasive strep A infections in that country, made headlines around the world. In Kenya, about 100 children aged 5 and younger died from invasive strep A infections over the same period — which did not make headlines.

Group A Streptococcus bacteria, also known as strep A, are responsible for mild infections such as sore throat, impetigo, and scarlet fever. They also cause more serious invasive diseases like bloodstream infections, toxic shock syndrome, and necrotizing fasciitis, the so-called flesh-eating disease. Infection with strep A bacteria can also trigger lifelong autoimmune diseases like rheumatic heart disease.

Globally, there are an estimated 1.8 million new strep A infections each year, responsible for more than 500,000 deaths. Most of these deaths occur in individuals with severe strep A disease, which is most common in children and older adults.

In Europe, the rapid increase in cases over a short time may be due to increased transmissibility and a lack of immunity and exposure to strep A during prolonged pandemic lockdowns followed by the resumption of social mixing. It is also possible that the bacteria may have acquired new genes, or that resistance to antibiotics is increasing.

The situation in low-income countries, which bear the brunt of strep A infection, presents tremendous challenges. One is the difficulty of getting an accurate diagnosis, given the absence of laboratory facilities, especially in remote or rural settings. Without a diagnosis, it’s difficult to begin timely treatment. Compounding matters is that strep A is not a notifiable disease in many low- and middle-income countries, meaning they collect little systematic data on it.

Rheumatic heart disease represents the highest burden of disease related to strep A. It is characterized by irreversible damage to the heart’s valves, heart failure, complications during pregnancy, and other difficult-to-manage conditions that often lead to premature death. Rheumatic heart disease is far more common in low-resourced countries and among indigenous people living in high-income settings. In these environments, strategies to improve the early diagnosis and treatment of strep A infections to interrupt its downstream consequences are urgently needed.

The severe impact of strep A diseases in low-income settings, including chronic illness and death, stands in contrast to the dearth of funding for operational research to address this gap and inform disease-control programs.

Programs such as the AFRO Strep Study, a registry of strep A infections across Africa, and the Missing Piece Surveillance Study, which focuses on Aboriginal people in Australia who have the highest rates of rheumatic heart disease in the world, are underway to provide data needed to identify effective prevention and treatment strategies as well as track antibiotic resistance and the evolution of various strains of strep A. Data from these initiatives will also ensure that the development of novel vaccines incorporate epidemiologic and strain-level data from low-resourced settings, which would have an important bearing on vaccine efficacy in populations where an anti-strep A vaccine is most needed.

The death of any child, or the onset of a lifelong disease, due to a strep A infection is tragic. The burden of these diseases in low-income countries has long been overlooked. It’s time for them to get the attention they need.

Dylan D. Barth is a research associate and epidemiologist at the Telethon Kids Institute and postdoctoral research fellow at the University of Western Australia in Perth. Mark E. Engel is a professor of Medicine, health researcher and epidemiologist at the University of Cape Town, South Africa. The opinions expressed here are those of the authors and do not necessarily represent the views of their affiliated institutions.

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