Polio vaccine poliomyelitis per million doses given. This compares with 5,000 cases per million who are paralysed following a polio infection. Both are generally safe to give during pregnancy and in those who have HIV/AIDS but are otherwise well. The first polio vaccine was the inactivated polio vaccine. It was developed by Jonas Salk and came into use in 1955. The oral polio vaccine was developed by Albert Sabin and came into commercial use in 1961. They are on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in
David Bruce (microbiologist) discouraged the experiments being carried by Zammit, and doubted his ability as a microbiologist. Eventually, when he learned of the positive results linking the fever with unpasteurized goat milk, Bruce tried to discredit the role of Zammit and take credit to himself. To a certain extent he succeeded, as it was renamed after him as brucellosis, however information about the role of Zammit has eventually surfaced. When he was transferred to South Africa, Bruce was sent to Zululand in 1894 to investigate the outbreak of cattle disease which the native called "nagana". In 1903, he identified the causative protozoan, and