Since the beginning of the year 2017, Chinese health authorities repeatedly warn that H7N9 avian flu propagation is accelerating in the country. The new epidemic wave has begun in October 2016. It has reached half of the country and started to spread across borders. Even if the outbreak still remains "controllable", the spread of the virus in birds is "unusually" fast and new cases rate in humans is the higher since the strain H7N9 has emerged in 2013.
Since the first avian flu confirmed cases in humans in 2013 in mainland China, around 1,500 people have been infected, with almost 600 fatal cases. The current outbreak is the 5th epidemic wave since 2013. It is different from the previous waves because the number of human infections increase abruptly: over 600 cases since October 2016, 121 deaths during the first 3 months of 2017. According to the FAO, 28 provinces and municipalities are affected. In Hong Kong, 5 imported cases have been detected since the begining of the 5th wave. The virus circulates quickly in animals, and is more easily transmitted from birds to humans compared to earlier epidemics. In most cases, symptoms are severe, and 40% of cases have been fatal. No human vaccine is currently available, and most humans are "immunologically naïve" to this novel virus strain.
In this context, colleagues at the Institut Pasteur of Shanghai-Chinese Academy of Sciences have developed a vaccine candidate by cloning the H7N9 haemagglutinin (HA) gene into an adenoviral vector in collaboration with researchers at Soochow and Fudan universities. This vaccine candidate induces a potent immune responses in mice and effectively protects animals from lethal H7N9 viral challenge, involving both HA-specific humoral immunity and cellular immunity.
The publication: Both haemagglutinin-specific antibody and T cell responses induced by a chimpanzee adenoviral vaccine confer protection against influenza H7N9 viral challenge, Scientific Reports 7, Article number: 1854 (2017) doi:10.1038/s41598-017-02019-1
Wang X, Fu W, Yuan S, Yang X, Song Y, Liu L, Chi Y, Cheng T, Xing M, Zhang Y, Zhang C, Yang Y, Zhu C, Zhang X, Xiong S, Xu J, Zhou D.