Strep A is a bacterial infection that can infect both children and adults. Worldwide, 750 million people are affected by Strep A, which leads to over 500,000 deaths each year. The infection is caused by the bacterium Streptococcus pyogenes and is transmitted through contact with contaminated surfaces or through the air. For example, individuals infected with Strep A can get others sick by coughing or sneezing. Symptoms include fever, sore throat, swollen lymph nodes, red rash, blisters, inflammation of tonsils and others. Many patients experience strep throat, which strictly includes fever, sore throat, and swollen lymph nodes.
Fortunately, Strep A can be treated using antibiotics and most patients are feeling better within a week. However, aggressive cases may lead to hospitalization and could be fatal. In rare cases, Strep A can induce rheumatic fever, which causes inflammation throughout the body and damages the heart, joints, and brain. Other fatal side effects caused by Step A include glomerulonephritis or kidney inflammation and necrotizing fasciitis, which destroys skin and muscle tissue. While most cases can be resolved easily, those with compromised immune systems should take extra precautions. Physicians list ways to prevent contracting Strep A and spreading it, including frequently washing hands, avoid touching your face, covering your mouth when coughing, stay home and rest if you feel symptomatic, and getting vaccinated against the flu.
Due to the high prevalence of Step A, physicians and scientists are working to develop an effective Strep A vaccine. Interestingly, a Strep A vaccine is one initiative the World Health Organization (WHO) is working toward, as a coordinated response to rheumatic fever and heart disease. Fortunately, scientists are making progress on a vaccine, accelerating efforts to overcome a common infection.
A recent paper in Nature Communications, by Dr. Andrew C. Steer and others, demonstrated that a diverse antibody response to specific infectious proteins are necessary for an effective vaccine treatment. Steer is a Director of Infection, Immunity, and Global Health at the Murdoch Children’s Research Institute in Melbourne, Australia. His research focuses on pediatric infectious diseases and tropical diseases, including scabies, Strep A, and rheumatic heart disease.
Steer and his group employed the world’s only human model for Strep A to uncover how specific antibodies respond to symptoms of Step A. The human model includes infecting healthy adults with bacterium in a controlled environment and then inject the vaccine to see how well the participant responds. This is a new and safe way to test vaccines and every individual voluntarily consents to participate in this work.
Researchers used this model to test 25 healthy adults that were exposed to low concentrations of Strep A. In this context, the exposed individuals already had antibodies against strep A. As a result, many of the participants were protected from being re-infected with the bacterium. Researchers were able to measure antibody concentrations in these participants and learn how humans respond to infection. Previously, there were major gaps in understanding how our immune systems generate a response to the bacterium. This work improves our understanding of which antibodies are critical to generate beneficial Strep A clinical outcomes. Importantly, this work can help enhance bacterial vaccines and reduce aggressive cases of Step A.
Paper, Nature Communications, Andrew C. Steer, Murdoch Children’s Research Institute, human model
