THE PLAGUE is best known for wiping out as much as a third of Europe’s population during the Black Death pandemic of the 14th century, but it’s not entirely a thing of the past. It’s enough of a present-day threat—either as a potential bioterrorism weapon or because some strains are now antibiotic-resistant—that some scientists are trying to develop a vaccine.
Dr. Ashok Chopra and a team of researchers at the University of Texas Medical Branch at Galveston recently published a study in the journal Nature of the three newest vaccine candidates. “So far, it looks very promising, at least in the two animal models we have tested,” says Chopra, a professor of microbiology and immunology. He began studying the bacterium that causes the plague, Yersinia pestis, around 2002.
His move into plague research followed the anthrax attacks of 2001, when letters containing anthrax were mailed to media outlets and congressional offices. Congress required the departments of Health and Human Services and Agriculture to regulate certain biological agents and toxins that could pose a severe threat to public health. The bacteria responsible for the plague made the top section of the list—Tier 1, the microbes most likely to be used as bioterrorism agents, alongside anthrax, Ebola and smallpox.
But 2001 wasn’t the first time the plague was considered a potential bioterr weapon, says Dr