In a preclinical study, an experimental vaccine designed by Inovio Pharmaceuticals ($INO) to combat the virulent, newly emerging H7N9 avian influenza caused cellular immune responses that could not only reduce the severity of the infection in a person who catches the virus but also limit the spread of the deadly flu strain in a pandemic setting.
In a preclinical study of its influenza DNA vaccine against the H7N9 flu virus, which originated in China early this year, 100% of the vaccinated animals were protected against sickness and death when they were given a lethal dose of H7N9 virus, according to a company news release. In addition, 100% of the vaccinated animals stayed healthy without any weight loss, a key indicator of health. The positive data comes on the heels of a June report by the company that its flu vaccine achieved immune response levels exceeding what are considered protective levels in other common influenza subtypes in a mouse study.
As of July 4, the World Health Organization (WHO) has been informed of a total of 133 laboratory-confirmed cases, including 43 deaths. So far, there is no evidence of sustained human-to-human transmission, but until the source of infection can be identified, WHO said in a recent H7N9 update that there will likely be more cases of human infection with the virus.
To create a vaccine that has broad protective properties against various H7N9 strains, Inovio researchers used a synthetic consensus design approach to construct a universal DNA vaccine that targets the HA influenza antigen based on sequences collected from several patients infected with H7N9. Mice were given the vaccine twice three weeks apart and were then exposed to a lethal dose of the A/Anhui/1/13 strain of H7N9 virus 4 weeks after the second vaccination. All vaccinated animals survived without weight loss, while unvaccinated mice demonstrated up to 30% weight loss and died within 8 days.
The company claims the study is the first to demonstrate that an H7N9 flu vaccine can protect against this newly emergent influenza subtype. Detailed study results will be presented at the TEPIK/APACI International Influenza Symposium in Seoul, South Korea, on July 12.
- here's the press release