New research examines preparedness for smallpox attack

A new study suggests that comprehensive health system planning can stymie the effects of a deliberate release of smallpox in a city, a nightmare scenario for public health officials.

The research, which was published today in the online journal PLOS One, said that if a health system response is not planned, rapid, and coordinated, it would require 100 percent of hospital beds with an epidemic lasting up to 300 days. However, if 95 percent of patients are isolated as soon as they become symptomatic, outbreak control could be achieved within 100 days.

The study was conducted by the Kirby Institute at the University of New South Wales (UNSW) in Sydney, Australia and is the first globally to monitor health-system requirements for a smallpox deliberate release.

“While infectious disease outbreaks are inherently unpredictable, there are many factors we can control and mitigate, to ensure epidemics are stopped rapidly,” said Raina MacIntyre, head of the Biosecurity Program at the Kirby Institute at UNSW. “It is essential to plan for health system surge capacity, both human resources and physical space requirements, in order to minimize the impact of potential bioterrorism attacks.”

The study pinpoints specific bottlenecks which can result in severe epidemic. These include physical space and staffing to isolate cases of smallpox, staff to track and vaccinate their contacts, resources to protect healthcare workers, and the ability to act quickly. Smallpox was eradicated in 1980 but has become a renewed security concern since a close relative of smallpox was created in a lab in 2017.

The researchers modeled a smallpox outbreak scenario in Sydney, which has a robust health system in place. The authors estimate a workforce of more than 100,000 clinical health care workers and almost 15,000 hospital beds in the city. However, the study found that with each day of delay in a coordinated response, the ability to isolate infected patients and to track and vaccinate their contacts becomes more difficult and can significantly influence the size of the epidemic.

While a small attack could require 4 percent of all hospital beds (more than the requirements for seasonal flu) for smallpox patients, a large attack would require more hospital beds than are available, within just 40 days, with corresponding surge requirements for clinical health care workers. Surge will also be required for the public health workforce and nurse immunizers to track and vaccinate contacts of infectious cases, which is essential for stopping ongoing transmission.

The research was funded through the NHMRC Centre for Research Excellence for Integrated Systems for Epidemic Responses.