Passive immunization for influenza through antibody therapies, a review of the pipeline, challenges and potential applications

The Global Action Plan for influenza vaccines (GAP) aims to increase the production capacity of vaccines so that in the event of a pandemic there is an adequate supply to meet global needs. However, it has been estimated that even in the best case scenario there would be a considerable delay of at least five to six months for the first supplies of vaccine to become available after the isolation of the strain and availability of the candidate vaccine virus to vaccine manufacturers. By this time, the virus is likely to have already infected millions of people worldwide, causing significant mortality, morbidity and economic loss. Passive immunization through broadly neutralizing antibodies which bind to multiple, structurally diverse strains of influenza could be a promising solution to address the immediate health threat of an influenza pandemic while vaccines are being developed. These products may also have a role in seasonal influenza as an alternative to other options such as antivirals for the treatment of severe acute respiratory illness due to influenza. This article provides an overview of the current clinical pipeline of anti-influenza antibodies and discusses potential uses and the challenges to product development.