Why H7N9 (Shanghai 2013) is the new stealth virus and what we can do about it.
PROVIDENCE, R.I., April 13, 2013 /PRNewswire/ — Full Story – http://bit.ly/H7N9EpiVax
The H7N9 emerging from China is a stealth virus. State of the art bioinforamatics tools have enabled EpiVax to predict that it will be hard to make vaccines and diagnostics for the new H7N9 flu virus (also called H7N9A/Shanghai/1/2013). H7N9 has fewer T cell epitopes than most previously circulating strains of flu, meaning that it may be able to fly under the immune system’s radar. Making a rapid diagnostic test may also be difficult. A quick test for H7N9 is not yet widely available. Individuals, who are infected, but not yet symptomatic, can get on a plane and go to New York, Tokyo, or London, without being detected. Thus, EpiVax believes that H7N9 “stealth virus” has serious potential for rapid expansion on a global scale.
What is the basis for this opinion? The “FastVax” team at EpiVax examined the H7N9 flu sequence and found an unusually LOW number of T cell epitopes in the outer proteins of the virus, “HA” and “NA”. Low T cell epitope content means infected individuals will have a difficult time making antibodies to H7N9. And quick blood tests like ELISAs will be very challenging to develop. While PCR is available, lacking an ELISA, will make it difficult to test the large numbers of exposed individuals, such as the 760 individuals that have already been exposed.
The analysis done by the EpiVax team is consistent with reports that previous H7 vaccines for similar viruses had low immunogenicity; H3N2 is also shown to be low immunogenicity by EpiVax and outbreaks of H3N2 among vaccinated individuals support the prediction.
There is an alternative approach to making an H7N9 vaccine. That approach is to make an epitope based vaccine – one version, named FastVax, has already been designed by EpiVax. Collaborators will begin to produce the vaccine next week.
Now is the time to ‘think outside the box” and try out alternative approaches to making influenza vaccines. EpiVax has one potential solution, and the FastVax team at EpiVax is also offering to analyze any other candidate vaccine for immunogenicity and cross-conservation with emerging H7N9 influenza sequences.
Full story with references/publications – http://bit.ly/H7N9EpiVax
Anne S. De Groot MD
SOURCE EpiVax, Inc.