ED suffered most from H1N1 spread

High rates of infection from exposures

As the novel H1N1 influenza began to spread last year, emergency department workers were at greater risk of infection than workers in other departments, according to a study at New York Presbyterian Hospital in New York City.

That finding may not seem surprising. But it highlights the differences in exposure risk within a hospital and the need for greater awareness and compliance with protective measures and policies, says co-author Robert Bristow, MD, FACP, director of Emergency Preparedness at Columbia Medical Center and medical director of Emergency Management at New York Presbyterian Hospital.

In fact, a delay in establishing clear protocols for personal protective equipment and management of suspected cases increased the risk of exposure in the emergency department, Bristow says. As the novel H1N1 emerged, there was some conflicting guidance from the Centers for Disease Control and Prevention and the state and city health departments.

"We actually had patients presenting before we developed a policy and educated the staff," he says. New York Presbyterian has since developed algorithms for patients presenting with acute febrile respiratory illness and exposed health care workers.

An analysis of absenteeism records for April through June 2009 found 123 confirmed cases of novel H1N1 influenza among about 6,000 employees at two medical centers, a pediatric hospital, a community hospital and a behavioral health facility. About 49% of those cases were among individuals in the adult and pediatric emergency departments, the pediatrics department and the intensive care unit, although those units only represented 19% of the total population of health care workers.1

Physicians had the highest infection rate, at 6.7%. In the emergency department, the onset of their illness coincided with patients coming from the community. "They got sick sooner [than health care workers elsewhere in the hospital] and their peak of infection correlated more with the peak of infection in the community," says co-author Cynthia Santos, an emergency preparedness research fellow at Weill Cornell Medical School.

In the three-month period, 30% of the health care workers in the pediatrics department became infected with H1N1, as did 24% of the adult emergency department.

For other departments, the pattern of illness indicated a possible nosocomial spread – infected employees spreading influenza to co-workers, she says. Interestingly, social workers had the lowest infection rate of the employee groups analyzed in the study but the highest increase in sick hours. They may have failed to have the H1N1 testing or may have stayed home for other reasons, says Santos. "They might have taken sick leave to take care of loved ones or because they were afraid of becoming sick themselves," she says.

The study helps identify which health care workers should receive priority vaccination if vaccine is in short supply, says Bristow. And it underscores the need for education about infection prevention, he says.

"We've taken the lessons we've learned and made policies and procedures that allow us to mitigate and to prevent the higher rates in the [at-risk departments]," he says.

Now, in huddles before, during or after shifts, health care workers are reminded of the importance of infection control protocols. Hospital epidemiologists occasionally observe in the emergency department to monitor compliance.

Adherence to sick leave policies is also important, says Bristow. As the pandemic peaked, ill health care workers often returned to work too early, potentially exposing co-workers or patients, says Bristow. The hospital then adopted a policy requiring employees to report to Workforce Health & Safety before returning to their units, he says.


1. Santos CD, Bristow RB, Vorenkamp JV. Which health care workers were most affected during the spring 2009 H1N1 pandemic? Disaster Med Public Health Preparedness 2010; 4:1-8.