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By Gary Evans, Medical Writer
While there are reports of various Zika vaccine trials proceeding, one the most promising methods to quickly and accurately measure vaccine efficacy has come to a full stop.
“Human challenge trials,” or “controlled human infection models,” involve exposing research subjects to a pathogen, typically in some attenuated state under rigorous controls and oversight, to test a vaccine candidate. With regard to Zika virus, a bioethics committee convened by the National Institute of Allergy and Infectious Diseases (NIAID) has concluded at present the risks of this approach outweigh the benefits. Among other reasons, the panel cited the risk to research subjects, possible transmission to others, and the availability of safer vaccine trial approaches.
Though a way forward is described in the panel’s recent report to NIAID, for now a red flag has been raised and human infection trials for Zika vaccines are being reconsidered. A researcher who helped develop a controlled human infection model for dengue virus — which is closely related to Zika — questioned the panel’s decision, saying it thwarts the fastest method to develop safe, effective vaccines.
“There are significant questions with Zika that a controlled human infection model could really answer,” says Anna P. Durbin, MD, a professor and researcher in the Johns Hopkins University Vaccine Initiative. “I am not sure the committee had adequate information in making their recommendation. I think they overstepped. There is a pathway forward in the recommendations, but unfortunately it is a very narrow pathway and it does limit the value of the controlled human infection model.”
For more on this story see the May 2017 issue of IRB Advisor
Gary Evans has written about infectious diseases, occupational health, medical ethics and a variety of other healthcare issues for more than 25 years. His writing has been honored with five awards for interpretative and analytical reporting by the National Press Club in Washington, DC.