CDC Confirms Four New Cases of Oseltamivir (Tamiflu)-Resistant H1N1
Tests performed by the Centers for Disease Control and Prevention (CDC) at the request of infectious disease experts at Duke University Medical Center have confirmed this week that isolates from four patients with H1N1 influenza at Duke University Hospital over the past six weeks were found to be resistant to oseltamivir (Tamiflu).
Two oseltamivir-resistant H1N1 isolates were reported in western North Carolina earlier this summer.
A team of experts from CDC, State of North Carolina Public Health Department, Durham County Health Department, and the Duke Division of Infectious Diseases are now working collaboratively to better understand the nature of these cases.
All four isolates, or samples, were obtained from four patients in an isolated unit of one floor at Duke University Hospital. All four patients were very ill with underlying severely compromised immune systems and multiple other complex medical conditions.
"We’re partnering with all of the involved agencies to examine these cases," said Daniel Sexton, MD, professor of medicine and director of the Duke Infection Control Outreach Network (DICON).
"Our extensive investigation thus far has revealed that appropriate infection control procedures have been diligently practiced on this isolated unit, and throughout the hospital, and we have experienced no illness among employees taking care of these patients in the affected unit over this period of time."
According to CDC, patients with oseltamivir-resistant H1N1 have had similar, no more severe, illness than patients with oseltamivir-susceptible virus.
Furthermore, CDC reports that all confirmed cases of oseltamivir-resistant virus to date have been susceptible to zanamivir (Relenza), a second antiviral medication that is indicated for the treatment of H1N1. At this time, CDC does not recommend any changes in antiviral guidance.
There is no evidence these few cases represent a hospital-wide concern. Furthermore, the number of hospitalizations at Duke for H1N1 influenza has declined in recent weeks, consistent with new information released today by the North Carolina State Department of Health that documents overall declines statewide in hospitalizations, emergency room visits, and other such measures.
"I commend our team of infectious disease experts who have, since the emergence of H1N1 earlier this year, conducted incredibly thorough, detailed, and thoughtful surveillance in search of anything that might represent unique or new presentations of H1N1," said Kevin Sowers, RN, MSN, chief executive officer for Duke University Hospital.
Duke has a longstanding reputation for excellence in infectious disease surveillance and management as evidenced by the important role played by DICON throughout North Carolina. Also, over the past several months, Duke has initiated several innovative and important research projects to better understand H1N1.
Despite the declining prevalence of H1N1 in our region, Duke Medicine remains committed to strict infection control practices, and will ensure their consistency with CDC and State Health Department recommendations.
Aggressive H1N1 vaccination efforts directed to the hospital’s high-risk patient populations and patient care employees will continue as we receive vaccine supply.