‘Eleventh Hour’ exaggeration on smallpox

“Eleventh Hour”

“Containment” episode CBS, Nov. 6

The premise: Dr. Jacob Hood (Rufus Sewell) is a biophysicist and a science advisor to the U.S. government who investigates crises. An old friend, Dr. Calvert Rigdon (Oded Fehr), virologist and director of the Pennsylvania Health Department, asks Hood to come to a demolition site to help investigate an infectious outbreak.

Twenty-one construction workers are being isolated by men in contamination suits because some have fallen deathly ill with a severe respiratory infection, fever and fatigue, some with a blistery rash. One man escapes but coughs up blood and collapses, then is recaptured.

The group is moved to Rigdon’s lab, a Level 3 Biosafety research facility. Hood suspects a smallpox outbreak and thinks he has tracked it to a group of extremely ill Guatemalans who have entered the country. But when Rigdon looks at the Guatemalans’ viral isolate under the electron microscope, he discovers that their virus is round in shape, characteristic of the chickenpox virus, rather than square as expected with severe smallpox (variola major).

Hood eventually confirms smallpox in the construction workers. He discovers that Rigdon has been hiding samples of variola major in a storage area for the purpose of producing a better vaccine -- but the boxes were moved, samples were stolen, and one was opened, leading to the outbreak.

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The medical questions: Is a smallpox outbreak described accurately? The virus seems to be spreading almost instantaneously, but how long does it really take smallpox to spread? Would people potentially exposed to smallpox be moved to a Level 3 Biosafety facility? Are there still specimens of variola major in the world that could be mishandled and cause a new outbreak? Is it square-shaped as opposed to round?

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The reality: Outbreaks of severe smallpox, or variola major, have not been seen in the world since 1977 (in Somalia) and in the U.S. since 1949 (the virus still exists in some high-security labs). “The show’s clinical description is not entirely accurate for smallpox,” says Dr. Joel Ernst, chief of infectious diseases at the New York University Langone Medical Center. “Smallpox is characterized by fever and rash -- respiratory symptoms are not prominent.” Dr. Shawn Skerrett, infectious disease specialist and associate professor of pulmonary medicine at the University of Washington, adds that “casual contact is usually not sufficient for infection. Smallpox is not nearly as infectious as chickenpox.”

The show seems to exaggerate the rapidity with which smallpox spreads. “The incubation period would typically be eight to 12 days,” says David Daigle, senior spokesman for the federal Centers for Disease Control and Prevention in Atlanta. However, he adds, if a person were exposed to a lot of the virus at once -- say, from a concentrated sample in a test tube -- they might get sick sooner.

Containment may be achieved by keeping those who have been exposed to the virus from spreading it by sneezing, coughing or touching others, Skerrett says. A 2004 British mathematical modeling study showed that isolating 90% of symptomatic cases is sufficient to bring a contagion under control; effective tracing of people who’ve come into contact with those people brings the number closer to 100%. Daigle adds that the show is accurate when it details giving the smallpox vaccine to those who have been exposed: Using the vaccine in this way may prevent infection or diminish symptoms.

A Biosafety 3 lab is a facility equipped with special engineering and design features aimed at containing dangerous pathogens. Research on the smallpox virus is done in an even more stringent, Biosafety 4 lab. But these units are designed for laboratory procedures, not patient care. Moving people who may have been exposed to smallpox to a Biosafety facility is not necessary to achieve containment, says the CDC’s Daigle. Instead, adequate isolation could be achieved in an appropriately equipped treatment facility or hospital, with healthcare personnel who have been vaccinated against smallpox.

Finally, the show is accurate when it comes to the shape of the viruses. The chickenpox virus is round, and variola major is boxy -- or as Daigle terms it, “brick-shaped.”

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In The Unreal World, he explains the medical facts behind the media fiction. marc@doctorsiegel.com.