The National Institutes of Health has begun testing the H7N9 avian flu vaccine. This strain of the flu first emerged in China last year, with 135 confirmed human cases and 44 deaths. No H7N9 infections have been reported outside of China, and the virus hasn’t demonstrated sustained person-to-person transmission, but it could mutate at any time and pose a public health threat. The trials are sponsored by the National Institute of Allergy and Infectious Diseases (NIAID).
The H7N9 virus mostly occurred among people who live with live chickens. It’s difficult to tell which birds carry the virus, since it doesn’t cause serious illness in poultry. When people started getting sick in China, officials culled more than 111,000 birds nationwide and banned live poultry trading.
The two clinical trials will evaluate the vaccine made from inactivated H7N9 virus isolated in Shanghai, China. Some of the vaccines will be tested with adjuvants, or substances added to vaccines to increase the body’s immune response, and some will be tested without. Other H7 influenza viruses suggest that two doses of the vaccine without adjuvants may not produce an adequate immune response. But if a pandemic occurs, adjuvants can be used as part of a “dose-sparing” strategy, allowing more production and more people being vaccinated.
The first trials will have about 700 participants; the second, about 1,000. The studies are expected to conclude in December 2014. Throughout the trials, a panel of independent experts will closely monitor safety data at regular intervals. For more information, visit NIAID’s Influenza Web Portal.
