Environmental Factor, November 2011, National Institute of Environmental Health Sciences
NICEATM convenes international workshop on rabies vaccine testing
Stokes introduced breakout group co-moderators as they reported on findings of breakout session 1: Antibody Quantification (Serologic) Methods for Rabies Vaccine Potency Testing: Validation Status, Data Gaps, and Implementation Strategies. (Photo courtesy of NICEATM)
Lukas Bruckner, D.V.M., Institute of Virology and Immunoprophylaxis (IVI), Switzerland, led discussions on breakout session 2: In Vitro Antigen Quantification Methods for Rabies Vaccine Potency Testing: Validation Status, Data Gaps, and Implementation Strategies. (Photo courtesy of NICEATM)
NIEHS scientists Rear Adm. William Stokes, D.V.M., and Warren Casey, Ph.D., joined other scientists from around the world Oct. 11-13 at the “International Workshop on Alternative Methods for Human and Veterinary Rabies Vaccine Testing: State of the Science and Planning the Way Forward.” More than 70 scientists from 14 different countries, representing government, industry, and academia, attended the workshop.
Workshop participants reviewed new testing methods that may provide improved accuracy and efficiency, and developed recommendations to validate and implement their use. The new methods are also expected to further reduce, refine, by lessening or eliminating pain and distress, and eventually replace the use of animals for potency testing of human and veterinary rabies vaccines.
Combating a major public health problem
Rabies is a deadly disease that kills more than 70,000 people worldwide each year, and rabies vaccines are the most important resources available for prevention of rabies infections. In the U.S. and other developed countries, widespread use of veterinary rabies vaccines protects pets and wildlife from disease. This practice significantly reduces the risk to humans in these countries from exposure to infected wildlife and domestic animals. For those estimated 15 million people each year exposed to the rabies virus, post-exposure human rabies vaccination prevents disease and saves lives.
The current methods used to evaluate the effectiveness of each production lot of veterinary and human rabies vaccine involves vaccinating animals and then challenging them with the live rabies virus. This approach requires large numbers of laboratory animals and causes significant animal pain and distress. A workshop(hhttps://ntp.niehs.nih.gov/pubhealth/evalatm/3rs-meetings/past-meetings/vaccine-wksp-2010/index.html) organized last year by the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM)(https://ntp.niehs.nih.gov/pubhealth/evalatm/index.html) and the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM)(https://ntp.niehs.nih.gov/pubhealth/evalatm/iccvam/index.html) identified rabies vaccines as one of the highest priorities for research, development, and validation of alternative test methods for potency and safety testing.
New approaches for testing vaccines
“Promising new approaches to rabies vaccine testing are now available that are more humane and use fewer or no animals. The technology exists to put those approaches into practice now or in the near future,” explained Stokes, who is director of NICEATM. “These approaches are more humane, faster, cheaper, and more accurate. They're also safer for laboratory workers, as they don't require handling of live rabies virus.”
The goals of last month's workshop were to review the current state of the science of these methods, and to define efforts necessary to achieve global acceptance and implementation. The workshop was organized by NICEATM and ICCVAM, in partnership with the European Centre for the Validation of Alternative Methods, the Japanese Center for the Validation of Alternative Methods, and Health Canada. The workshop was hosted by the U.S. Department of Agriculture (USDA) Center for Veterinary Biologics at the recently established National Centers for Animal Health in Ames, Iowa. Having the workshop at this state-of-the-art research facility encouraged participation by scientists from USDA and the numerous vaccine manufacturers in the Midwest. The workshop was co-sponsored by the International Alliance for Biological Standardization.
Workshop participants reviewed a recent international study on a method that measures protective antibodies from vaccinated animals, to assess rabies vaccine potency. This method eliminates the need for challenge testing with live virus, thereby avoiding severe pain and distress to the test animals and providing for improved worker safety. An action plan was formulated to achieve global implementation of this alternative method. Workshop participants also reviewed the state of the science for methods that measure the specific protective protein in vaccines, as a way to evaluate potency without animal testing. Finally, workshop participants recommended steps that can be taken immediately to relieve animal pain and distress, including routine use of anesthetics and analgesics, and ways to reduce the number of animals required in the current potency test.
Presentations and a summary of recommendations from the workshop are available on the NICEATM-ICCVAM website(https://ntp.niehs.nih.gov/pubhealth/evalatm/3rs-meetings/past-meetings/rabies-wksp-2011/index.html). A workshop report will be published early next year in the journal Biologicals.
Biologics Working Group
NICEATM and the ICCVAM interagency Biologics Working Group (BWG) were primarily responsible for organizing the workshop. The BWG is co-chaired by Jodie Kulpa-Eddy, D.V.M., of the USDA, and Richard McFarland, M.D., Ph.D., of the U.S. Food and Drug Administration (FDA). Kulpa-Eddy is also currently chair of ICCVAM and the USDA's principal ICCVAM representative. In addition to the FDA and USDA, the BWG includes scientists from the Centers for Disease Control and Prevention, U.S Department of Defense, U.S. Department of the Interior, NIEHS, and the National Institute of Allergy and Infectious Diseases. Stokes and Casey are the NIEHS representatives on the BWG.