A new pandemic flu vaccine is effective in protecting 80% of people who receive it, says its maker, GlaxoSmithkline. A new additive was used to boost the vaccine’s effectiveness, this means only a small dose is needed. Sanofi-Aventis, another company that is getting a pandemic flu vaccine ready, had previously reported that theirs was only effective for 50% of people who got the shot.

Glaxo is among some thirty companies worldwide which are developing a new vaccine aimed at protecting humans from bird flu. Glaxo is testing two vaccines, one with a standard additive and another with a new additive.

The aim of the new additive is to get a stronger immune response from a low dose H5N1 vaccine. In other words, the additive, or adjuvant, makes the vaccine more powerful.

If a lower dose is needed, more people can be given the shot.

80% of the volunteers received 3.8ug of antigen and demonstrated a strong seroprotective immune response – well in excess of target criteria set by regulatory agencies for influenza vaccine registrations. GSK says no other H5N1 vaccine has shown such high efficacy results.

JP Garnier, GSK’s CEO, said “These excellent clinical trial results represent a significant breakthrough in the development of our pandemic flu vaccine. This is the first time such a low dose of H5N1 antigen has been able to stimulate this level of strong immune response. There is still a lot more work to be done with this programme, but this validation of our approach provides us with the confidence to continue developing the vaccine, including assessment of its ability to offer cross-protection to variants of the H5N1 strain. All being well, we expect to make regulatory filings for the vaccine in the coming months.”

The trial, which took place in Belgium, involved 400 healthy adults aged 18-60. The vaccine was produced from an inactivated H5N1 virus and a new adjuvant. Each participant was vaccinated twice during the trial. Four levels of antigen were tested – 3.8ug was the lowest dose tested.

Written by: Christian Nordqvist
Editor: Medical News Today