New research from the University of Leicester and University Hospitals of Leicester NHS Trust warns of a six-month time lag before effective vaccines can be manufactured in the event of a pandemic flu outbreak.
By that time, the first wave of pandemic flu may be over before people are vaccinated, says Dr Iain Stephenson, Consultant in Infectious Diseases at the Leicester Royal Infirmary and a Clinical Senior Lecturer at the University of Leicester.
In his paper published in PNAS - Proceedings of the National Academy of Sciences of the USA- Dr Stephenson makes the first case for a pre-pandemic vaccine to mitigate the worst effects of pandemic flu.
He said: "This study is the first to show an effective pre-pandemic vaccine approach. This means that we could vaccinate people potentially many years before a pandemic, to generate memory cells that are long lasting and can be rapidly boosted by a single dose of vaccine when needed."
Dr Stephenson, of the Department of Infection, Immunity and Inflammation at the University of Leicester, said: "If an influenza pandemic occurs, vaccination will to be the main way to protect the population. The major current threat seems to be from avian influenza H5N1 (bird flu) which has spread rapidly around the world and causes human infections and deaths.
"Unfortunately, if a pandemic occurs, it will take up to six months to manufacture effective vaccine, so the first waves of the pandemic may be over before people are vaccinated. Furthermore, most people need two doses of H5 pandemic vaccine to get protection- so this adds a further delay.
"To reduce any delay, we could consider stockpiling vaccine or immunizing people with vaccine prepared in advance -(a so called 'pre-pandemic vaccine' - to protect them before a future pandemic.
"However, we don't know which strain of influenza will cause the pandemic. There are several strains of H5N1 virus, so we can't be sure of which virus strain to make pre-pandemic vaccine from. Therefore a 'pre-pandemic' vaccine needs to give cross protection to as many H5 strains as possible."