The future of the flu vaccine?

Flu vaccines today have two major problems: they need to be administered every year, and are only effective against a small subset of flu strains.  Basically, the vaccine makers make an educated guess about which will be the most prominent strains in a given year, and then manufacture the vaccine based on that prediction.  Since different strains become prevalent in different years, this means that each new vaccine must be given when it’s developed each year. 

Damian Ekiert and Ian Wilson, along with Robert Friesen and Jaap Goudsmit from Crucell (a Dutch biopharmaceutical company), recently published a paper in Science Express that details their efforts to prevent and treat influenza infection using antibodies, which would avoid the problems of traditional flu vaccines. 

The project was started several years ago, when Goudsmit and other researchers at Crucell discovered an antibody that bound to a functionally important structure on the flu virus which exists in many different strains.  The antibody, CR6261, worked to both prevent and treat infections by about 50% of influenza viruses, including H1 viruses.  Crucell is about to begin early clinical trials of CR6261, according to the Scripps Research Institute.

To complement this, Crucell’s team began to search for another similar antibody that would be effective against other flu viruses, including H3 and H7 subtypes.  They discovered CR8020, an antibody which binds close to the viral membrane.  CR8020 appears to work by preventing the conformational changes that occur when a flu virus is taken up by a host cell, thereby blocking the release of the virus DNA into the host. 

As Ekiert et al. note in the publication, influenza A viruses responsible for human pandemics have come from very different strains.  In accordance with this, a near-universal therapy for influenza should protect against all these strains, if possible.  Though it is unknown how the antibodies will fare in clinical trials, a mixture of antibodies such as CR6261 and CD8020 is a potentially promising treatment for people who have contracted the flu.  Despite the challenges in developing the antibody mixture into a vaccine, there is now more hope that a “universal” vaccine can be developed.

Science Express paper: http://www.sciencemag.org/content/early/2011/07/06/science.1204839

Infection Control Today article: http://www.infectioncontroltoday.com/news/2011/07/discovery-of-natural-antibody-brings-universal-flu-vaccine-a-step-closer.aspx