Research, published by 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, said Dr Iain Stephenson, consultant in infectious diseases at the Leicester Royal Infirmary and senior lecturer at the University of Leicester. He added that most people need two doses of H5 pandemic vaccine to obtain protection, which adds further delay. Dr Stephenson made the first case for a pre-pandemic vaccine to mitigate the worst effects of pandemic flu. He said: “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. If an influenza pandemic occurs, vaccination will to be the main way to protect the population. “However, we do not 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 prepandemic vaccine from. Therefore a ‘prepandemic’ vaccine needs to give cross protection to as many H5 strains as possible.” Dr Stephenson and his team found that people who received H5 vaccine between 1999 and 2001 responded very well to a single dose of a newer H5 vaccine. They had memory cells that gave a rapid protective response within seven days of the repeat vaccine. Also the response was very broad and able to protect against all known strains of H5N1 virus. “In contrast, those people who had not been previously vaccinated with H5 vaccine, behaved as we had expected. They required two doses of vaccine and obtained good an tibody responses up to six weeks after the first dose.”
