Researchers find pre-pandemic vaccine can protect people
If a flu pandemic breaks out, it could take manufacturers up to six months to produce an effective vaccine. This could have devastating effects on the population since the first wave of pandemic flu may be over before people are vaccinated, researchers warn. Writing in the journal Proceedings of the National Academy of Sciences (PNAS), European scientists set out an effective pre-pandemic vaccine approach. 'This study is the first to show an effective pre-pandemic vaccine approach,' explains co-author Dr Iain Stephenson from the Leicester Royal Infirmary and the University of Leicester in the UK. '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.' A consultant in infectious diseases, Dr Stephenson notes that in the event of a pandemic flu outbreak, people will need to be vaccinated to safeguard their well-being. What also adds to the stress of such an outbreak is that not only will the production time to get effective vaccines to doctors' offices slow down the process, but also that the majority of people require two vaccine doses to ensure protection. 'To reduce any delay, we could consider stockpiling vaccine or immunising people with vaccine prepared in advance - a so-called "pre-pandemic vaccine" - to protect them before a future pandemic,' Dr Stephenson suggests. The problem, however, is that it is not clear to the experts which strain of influenza will trigger the pandemic. Dr Stephenson and his team focused their efforts on the avian influenza H5N1 strain of the disease, which has spread rapidly around the world and killed a number of people. 'There are several strains of H5N1 virus, so we can't be sure of which virus strain to make pre-pandemic vaccine from,' the researcher notes. 'Therefore, a "pre-pandemic" vaccine needs to give cross-protection to as many H5 strains as possible.' In order to test how effective a pre-pandemic vaccination would be, the researchers administered a dose of 1H5N1 vaccine to people who had never been vaccinated as well as to subjects who had been immunised at least six years earlier with the H5N3 vaccine (the subjects were recruited either at the University of Leicester or the University Hospitals of Leicester). Preliminary findings show that immune responses were induced following the booster vaccination. 'We found that those people who received H5 vaccine between 1999 and 2001 responded very well to a single dose of a newer H5 vaccine,' Dr Stephenson explained. '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.' According to Dr Stephenson, the findings add weight to the premise that people who have not been previously vaccinated with the H5 vaccine need two doses of vaccine, and get 'good antibody responses up to six weeks after the first dose'. Also participating in the study were Novartis Vaccines (Germany), the University of Siena (Italy), the Health Protection Agency (UK) and the Centers for Disease Control and Prevention (US). Whether these findings are relevant for the latest swine flu outbreak remains to be seen. The Emergency Committee of the World Health Organization (WHO) has raised its pandemic alert level of swine flu from phase 3 to phase 4, but has not declared a global emergency. In a statement to the press, the WHO notes the change to a higher phase of pandemic alert indicates that the likelihood of a pandemic has increased, but not that a pandemic is inevitable. The EU's Health Ministers will convene later this week (30 April) in an extraordinary meeting to evaluate the possible threat posed by the swine flu outbreak, as well as to coordinate efforts of the Member States. The European Commission's Directorate General for Health and Consumer Protection (DG SANCO) has said the Member States must notify them of measures they propose to take, measures and guidance issued, and any confirmed cases. DG SANCO will maintain permanent contact with the Member States, the WHO, the ECDC (European Centre for Disease Prevention and Control), as well as with the United States and Mexico through the Global Health Security Initiative which targets the prevention and detection of and response to biological threats. DG SANCO has pointed out that it will implement at EU level the global approach recommended by the WHO Emergency Committee.
Countries
Germany, Italy, United Kingdom, United States