Computer Model Maps Efficient Inoculation Of Hospital Staff In Pandemic Outbreak

The study by the Division of Outcomes and Effectiveness Research of the Department of Public Health at Weill Cornell Medical College is published in the May issue of the journal Infection Control and Hospital Epidemiology and reports the results of computer simulations comparing several inoculation strategies.

"During an infectious outbreak, it's vitally important that hospitals remain fully functioning. This study suggests that assigning each staff member a time for inoculation is the most effective method to ensure that our caregivers stay healthy and patients continue to receive optimal care," says Dr. Nathaniel Hupert, senior author of the study. He is assistant attending physician at NewYork-Presbyterian/Weill Cornell and assistant professor of public health and medicine at Weill Cornell Medical College.

Using discrete-event simulation -- a standard technique in operations research -- researchers compared two staff-management strategies with specific rules for dispensation and an unmanaged scenario in which staff would line-up for inoculation all at once or at the time of their choosing. In the scenarios, dispensing stations were located by existing hospital pharmacy outposts. Each station was run by three nurses and other support staff, administering medicine to 200 employees during an eight-hour shift, figuring an average dispensing time of five minutes each.

The method found to be the best, called the "ticket strategy" and inspired by the practice of customers taking numbers at a delicatessen, assigned staff members a specific time of day to receive prophylaxis based on a number such as the last digits of their identification badge. Assuming that 75 percent of staff followed the rules, the expected time in line would be only slightly more than two minutes. Waits were still much less than those of the unmanaged scenario, even if levels of compliance were as low as 25 percent

Another method, called the "flag strategy," allowed employees to get their inoculation at the time of their choosing -- but only when the line had fewer than a set number of people. With a queue maximum of five, this method resulted in a wait of more than four and a half minutes; with a queue maximum of three, it resulted in a wait of nearly three minutes. One major disadvantage was the many return trips necessitated when the line maximum was met.

Both staff-managed scenarios were a great improvement over an unmanaged 'free-for-all' scenario that in computer simulations resulted in wait-times as long as an hour -- time spent away from patient care. "Just having everyone line up at the start or end of the day would require a lot of nurses to give vaccinations, and nurses will be in short supply if or when an actual pandemic hits," explains Dr. Hupert.

Large hospitals, especially, face the challenge of inoculating tens of thousands of employees within one or two days amid stressful conditions and potentially extreme and unpredictable demands regarding patient-care, the paper said.

"While individual hospitals have initiated varying degrees of preparedness planning, there are currently no guidelines or best-practice examples for this aspect of hospital protection in recently released national health emergency plans. We hope that this study will represent the start of a coordinated effort to aid decision-making by public health officials and emergency management planners," says Dr. Wei Xiong, first author and instructor of public health at Weill Cornell Medical College.

The paper was an interdisciplinary collaboration between the Weill Cornell Department of Public Health, NewYork-Presbyterian Hospital management -- including Dr. Jaclyn Van Lieu Vorenkamp, director of occupational health -- and the Cornell University School of Operations Research and Information Engineering.

Additional co-authors included Drs. Eliot J. Lazar and Nicholas V. Cagliuso of NewYork-Presbyterian/Weill Cornell, Eric Hollingsworth of Weill Cornell Medical College and Dr. Jack Muckstadt of Cornell University's School of Operations Research and Industrial Engineering.

The study was funded, in part, by the U.S. Department of Health and Human Services (HHS), Agency for Healthcare Research and Quality (AHRQ) and Centers for Disease Control and Prevention (CDC) Division of Strategic National Stockpile.