New influenza vaccine research at the University of Leicester
New research published yesterday (Monday April 27) 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 an influenza pandemic. 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.
Pandemic preparedness plans show that vaccination is critical for controlling pandemics. Some authorities have invested in vaccine stockpiles, but these resources are small in comparison to global demand. The use of stockpiled vaccine is challenged by the need for two doses and secondary manufacturing constraints. MF59, a proprietary adjuvant, was licensed in seasonal influenza vaccines in 1997, and more than 30 million doses have been administered safely so far. These new findings suggest that consideration could be given to advance priming to induce memory responses that enable cross-reactive antibodies to be generated rapidly after infection with the pandemic virus or by a single low-dose vaccination when required at the onset of future pandemic.
Fast rise of broadly cross-reactive antibodies after boosting long-lived human memory B cells primed by an MF59 adjuvanted prepandemic vaccine. PNAS USA April 27, 2009
Proactive priming before the next pandemic could induce immune memory responses to novel influenza antigens. In an open-label study, we analyzed B cell memory and antibody responses of 54 adults who received 2 7.5-μg doses of MF59-adjuvanted A/Vietnam/1194/2004 clade 1 (H5N1) vaccine. Twenty-four subjects had been previously primed with MF59-adjuvanted or plain clade 0-like A/duck/Singapore/1997 (H5N3) vaccine during 1999–2001. The prevaccination frequency of circulating memory B cells reactive to A/Vietnam/1194/2004 was low in both primed and unprimed individuals. However, at day 21 after boosting, MF59-adjuvanted primed subjects displayed a higher frequency of H5N1-specific memory B cells than plain-primed or unprimed subjects. The immune memory was rapidly mobilized by a single vaccine administration and resulted in high titers of neutralizing antibodies to antigenically diverse clade 0, 1, and 2 H5N1 viruses already at day 7. In general, postvaccination antibody titers were significantly higher in primed subjects than in unprimed subjects. Subjects primed with MF59-adjuvanted vaccine responded significantly better than those primed with plain vaccine, most notably in early induction and duration of cross-reacting antibody responses. After 6 months, high titers of cross-reactive antibody remained detectable among MF59-primed subjects. We conclude that distant priming with clade 0-like H5N3 induces a pool of cross-reactive memory B cells that can be boosted rapidly years afterward by a mismatched MF59-adjuvanted vaccine to generate high titers of cross-reactive neutralizing antibodies rapidly. These results suggest that pre-pandemic vaccination strategies should be considered.
Related:
- 10 things you should know about H1N1 (swineflu)
- 10 more things you should know about H1N1 (swineflu)
Tags: Add new tag, Biology, Health, Influenza, Medicine, Microbiology, Science, University of Leicester, Vaccines, Virology
