July 26, 2006

scientists react to flu vaccine announcement

Scientists react to an announcement from GlaxoSmithKline (GSK) on the production of a new vaccine against H5N1 Influenza

Read the press release from GSK on their website

Dr Paul Digard, a virologist at the University of Cambridge, said:

“Preparing a vaccine against H5N1 influenza presents two big problems; firstly how to prepare sufficient vaccine in time, and secondly exactly which virus strain to produce a vaccine against.

“The results from GlaxoSmithKline are good news in that they seem to go some way to addressing the time problem – a smaller amount of vaccine needed per dose (3.8 µg compared with 15 µg for normal seasonal flu vaccine) meaning a shorter time required to produce many doses. However this problem may not be completely solved because the process of producing flu vaccine requires growth of the virus in eggs and unfortunately some strains of H5N1 do not grow well in eggs.

“Furthermore, it is impossible to predict the exact nature of the pandemic strain of the virus before it emerges and therefore we cannot solve the important second problem and thus cannot develop the correct vaccine in advance. Nevertheless, identifying an adjuvant/vaccine formulation that works for a related virus in advance is excellent news as at the very least it will significantly speed up production of whatever pandemic vaccine might be needed.”

Dr Azra Ghani, Reader in infectious disease modelling, London School of Hygiene and Tropical Medicine, said:

“This advance in H5N1 vaccine development is important from a public health perspective. Although there are a number of loops that need to be jumped before it is available for widespread use, it would be particularly helpful for such a vaccine to become available in the areas currently experiencing H5N1 so that, for example, if a case occurs in a village, other family members and villagers that have been in contact with the case could be vaccinated. However, a critical factor is the time taken for the vaccine to become effective in the individual – for a vaccine to be effective in the current outbreak setting it needs to be both deployed rapidly, highly effective and result in rapid protection in the individual.

“Clearly for pandemic influenza there may be differences in the virus so it is not possible to predict whether a vaccine against the current strain of H5N1 would be effective for a pandemic strain. However, vaccination is clearly an important strategy in slowing the spread of a pandemic and so it is important that vaccine development continues to be a high priority.”

Dr Colin Butter, an Immunologist at the Institute for Animal Health, said:

“Vaccines may use two arms of the immune system to help prevent infection with avian influenza virus. One of these arms is unlikely to be stimulated by the inactivated virus used in the GSK vaccine. Whether the remaining arm (the one used by conventional seasonal ‘flu jabs) will be sufficient to protect against a pandemic virus will depend on how closely such a virus resembles H5N1 and how good the vaccine is at getting the immune system to “see” a virus that is somewhat different. The results of cross-protection studies will indicate whether the vaccine is likely to be of value against an as yet unknown target.”

Dr Ronald R Cutler, Principal Lecturer in Infectious Diseases and Pathology at the University of East London, said:

“It is good news that this vaccine can produce a significant response from a relatively small dose. One of the main problems with previous H5N1 vaccines is that they required a large dose and the success rate was not good. The main problem with creating previous vaccines would therefore be the limits on manufacturing enough to treat sufficient numbers of the population. This new vaccine could be produced in greater volume. Although this vaccine may not be the one actually needed to treat the next avian flu pandemic, as the virus is continually changing, the benefit is that we now may have the technology to respond to a human pandemic H5N1 using inactivated virus and a novel adjuvant. There is however still a need to improve the production technology and reduce the time it takes to produce a new vaccine from a newly detected pandemic strain as there may still be a lag period of 3 – 6 months between first isolation of a pandemic strain and significant production of vaccine. The new GSK vaccine may produce some or significant protection against a new human H5N1 pandemic strain, we still do not know the answer to this question. Further trials in endemic areas would be needed to establish this.”

Nigel Horrox, president of the British Veterinary Poultry Association, said:

“This is a significant development in flu vaccines for human use and should, in time, provide us with another means of countering avian flu in man. In the event of an avian flu outbreak we look forward to this and similar products being made available to those working in close contact with affected poultry in the field.”

Ian M Jones, Professor of Virology at the University of Reading, said:

“It’s essentially a “bangs per buck” argument. Glaxo have used a standard H5 vaccine but formulated it with their propriety adjuvant to effectively lower the dose at which a protective response is seen. That means the vaccine is an affordable option ahead of a pandemic emerging.

“The H5 component of the Glaxo vaccine is a standard killed preparation much as is used in seasonal vaccines. It’s not cutting edge technology but it offers advantages when compared to the more novel DNA or VLP based vaccines suggested by competitors in that regulatory approval ought to be quick.

“Adjuvants are the other big story in vaccine development. They stimulate the immune system so it is more receptive to the materials used. Glaxo’s adjuvant was shown to be effective during the development of their HPV vaccine Cervarix and the current data shows the same is true for influenza. Effectively lowering the dose of the vaccine is an important parameter for use in the real world where both costs and manufacturing capability may be limiting.”

Peter Dunnill, Chairman of The Advanced Centre for Biochemical Engineering, UCL, said:

“1. The advance with a more modern adjuvant is important.

2. It would still only allow coverage of 5% of the global population if all the worlds viral influenza vaccine capacity was used.

3. Each production cycle in hens eggs takes about 6 months whereas a pandemic form could arrive in weeks by so called ‘jet spread’.

4. Only the USA is investing in major new and modern cell based culture for influenza vaccine. The US government is investing $1 billion alongside $1 billion from companies to cover its 300 million population. It will take 4-5 years to come on stream and produce vaccine in 3-4 month cycles. For the rest of the world to achieve this would cost $43 billion. That is unlikely to happen.

5. There are now non-viral vaccines which could be made in existing pharmaceutical plants e.g. a hemagglutinin protein vaccine or a DNA vaccine. The hemagglutinin protein vaccine has completed clinical trials. It may also be possible to convert some avian influenza vaccine facilities to human and statins may address the so called cytokine storm of the immune system which probably kills many patients.”