Ebola: What the Next Week Will Tell Us About America's Risk

A Centers for Disease Control and Prevention training session for health care workers treating Ebola victims in Anniston, Alabama, on Oct 15 Photograph by Erik S. Lesser/EPA

In response to the second Dallas hospital worker diagnosed with Ebola, the Centers for Disease Control has already moved to change its guidelines on how health-care workers protect themselves. What happens in the next seven days will tell us a lot about the potential risk to the medical professionals facing any future Ebola cases in the U.S.

CDC officials believe workers at Texas Health Presbyterian Dallas faced the greatest danger of infection after the Liberian man who eventually died at the hospital, Thomas Eric Duncan, was first admitted on Sept. 28 but before lab tests confirmed an Ebola diagnosis three days later. “Our investigations increasingly suggest that the first several days before the patient was diagnosed appear to be the highest-risk period,” CDC Director Tom Frieden said Wednesday in a media briefing. The two nurses who became infected had “extensive contact” with the patient during that three-day period, while he was vomiting and had diarrhea.

Duncan was isolated at that time, and the hospital says nurses followed CDC guidelines. But the recommendations were changing, and the union representing nurses has said protocols were missing or inadequate. “When the CDC issued updates, as they did with leg covers, we followed their guidelines,” the hospital said in an e-mail today. The hospital didn’t initially have Tyvek isolation suits, and some in the first batch that arrived were too big for the nurses. “It is possible that nurses used tape to cinch the suits for a better fit,” according to the hospital’s statement.

There’s a lot we don’t know, but this much is clear: In the first days that Duncan was hospitalized, hospital workers had never before seen Ebola. That alone raises the risk that they were inadvertently exposed to a virus that, by all accounts, requires meticulous procedures to prevent seriously ill patients from infecting caregivers.

It takes as long as 21 days between when someone is infected with Ebola and when they develop symptoms. If other workers contracted the virus from Duncan between Sept. 28 and Sept. 30, the window in which they’d get sick closes around Oct. 21. The CDC is “planning for other eventualities in case we get additional cases in the coming days,” Frieden said.

The agency is monitoring about 50 hospital workers who entered Duncan’s room during his treatment. That includes the the entire time he was hospitalized, not just the first three days before Ebola was confirmed. Duncan had contact with another 48 people before he was admitted. None has so far shown signs of illness, according to the CDC. The 21-day incubation period will close for them this weekend. Other people who had direct contact with the stricken health-care workers are also being monitored.

Other workers may have been infected while caring for Duncan between his diagnosis Sept. 30 and his death eight days later. Although stricter safety protocols were in place at the hospital by then, critics are questioning whether those were adequate and followed properly. Whether anyone was exposed to Duncan’s body or contaminated linens during removal and cleaning is another question. The CDC hasn’t focused on this as a risk. Then again, until this week, the agency hadn’t considered Duncan’s caregivers to be in danger, either.

There’s also the possibility that more people who contracted the virus in West Africa, where the epidemic remains uncontrolled, will develop symptoms in the U.S. This could include doctors and aid workers as well as other travelers. By now the CDC and U.S. hospitals are on heightened alert, and Frieden has promised to send a CDC response team to any U.S. hospital where Ebola is diagnosed to ensure workers’ safety.

Given the lack of preparation in the days before Duncan’s diagnosis in Dallas, that appears to be one of the highest-risk periods for spreading the virus in the U.S. The public should know how many people were infected in that window by this time next week.

    Before it's here, it's on the Bloomberg Terminal.