History of vaccination

hosts originated with Calmette and Guérin, who passaged bovine tuberculosis bacteria 230 times in artificial media to obtain an attenuated strain to protect against human tuberculosis (11). Later in the 20th century, Sellards and Laigret (12) and, more success-fully, Theiler and Smith (13) attenuated yel-low fever virus by serial passage in ... ................
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