New model could help test vaccines against the deadly Strep A bacteria Researchers have successfully developed a new Strep A human challenge model, paving the way to test vaccines against the common deadly bacteria that causes sore throats, scarlet fever and skin sores. The collaborative research effort, led by the Murdoch Children's Research Institute (MCRI) and published in The Lancet Microbe, found the model, which deliberately infected healthy adult volunteers with the bacteria in a controlled environment, was safe and would now be used to trial Strep A candidate vaccines. Strep A infections affect about 750 million people and kill more than 500,000 globally every year - more than influenza, typhoid or whooping cough. Strep A can also cause severe life-threatening infections like toxic shock syndrome and flesh eating disease and post-infectious illnesses such as acute rheumatic fever, rheumatic heart disease and kidney disease.