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Vaccinations Against Bird Flu Should Happen Now, Say Experts

The report says that if pre-priming with an H5N1 vaccine becomes an acceptable strategy, thought should be given to including this in the regular seasonal flu vaccines.

The experts say that although it is still unclear if a bird flu pandemic will emerge, because of the potential high death rate and huge economic cost "we simply cannot afford to ignore it as a major global threat." They point out that estimates of global deaths from bird flu have suggested that up to 350 million people could die.

The candidate vaccine contains the bird flu strain H5N1 and an adjuvant called MF59.

He added: "If governments are thinking about stockpiling vaccine, you could actually be stockpiling it in people's arms."



http://www.medicalnewstoday.com/articles/128049.php

Vaccinations Against Bird Flu Should Happen Now, Say Experts

People should be vaccinated now against bird flu rather than waiting for a global pandemic to erupt, an international panel of experts - including a leading British influenza specialist - say in a new report. 1

The influenza researchers say the World Health Organisation (WHO) and national governments should give "urgent consideration" to the idea of priming people in advance of bird flu with a preparatory vaccination.

The idea is to give people a vaccination now against bird flu to build up the immune system, while there is still plenty of time to organise the programme, then give them a booster shot when the pandemic is imminent. The primed people could be protected in a week as opposed to six weeks. 2

The experts, including Professor Karl Nicholson, from Leicester University, state: "We think that WHO and governments should give urgent consideration to the potential risks and benefits of priming people who would be at greatest risk of infection if a pandemic of H5N1 influenza were to emerge (frontline laboratory and health-care workers), with the view to cautiously introducing a programme of immunisation."

In a report in the latest edition of the journal Lancet Infectious Diseases the researchers point out that a conventional vaccination policy against bird flu requires two doses of H5N1 vaccine before people are protected "which may be logistically difficult to organise".

They say there may be no warning before a pandemic suddenly appears, as the early danger signs may be missed.

"However, pre-pandemic priming has the potential to evoke a more rapid antibody (defence cell) response that might ameliorate the disease, cutting hospital admissions, deaths, and onward transmission of the virus," say the doctors.

The report says that if pre-priming with an H5N1 vaccine becomes an acceptable strategy, thought should be given to including this in the regular seasonal flu vaccines.

The experts say that although it is still unclear if a bird flu pandemic will emerge, because of the potential high death rate and huge economic cost "we simply cannot afford to ignore it as a major global threat." They point out that estimates of global deaths from bird flu have suggested that up to 350 million people could die.

The report concludes: "The maximum benefit from using a pre-pandemic vaccine may be gained from priming populations before there is evidence of a novel virus emerging and spreading, when systematic supply, distribution and vaccination strategies can be put in place."

Just a few weeks ago a team of researchers from Leicester University, including Professor Nicholson, together with vaccination experts from the Health Protection Agency, gave details of a British study showing that pre-priming people could give protection against bird flu within a week. 2

That study, released in a letter to the New England Journal of Medicine, looked at an experimental pre-pandemic vaccine being developed by Novartis Vaccines.

The candidate vaccine contains the bird flu strain H5N1 and an adjuvant called MF59. (An adjuvant is a substance used to improve the response of the immune system to a vaccine.)

The study looked at how quickly people mounted a protective immune response against H5N1 if they had already been pre-vaccinated with a different kind of flu vaccine, using a strain known as H5N3 together with MF59.

The pre-vaccinated people received their first vaccination between 1999 and 2001 as part of earlier studies.

Two groups, involving around 60 British patients, were involved in the study - one set who had been pre-vaccinated and another set that had not.

By day seven 80% of the primed group showed a protective response after one shot of the adjuvanted vaccine compared to 20% in the un-primed group.

Study investigator Dr Iain Stephenson, from University Hospitals Leicester, said: "With the pre-priming approach you could choose certain groups in advance, for instance health care workers, and almost vaccinate at leisure. Then you would only a need a week to provide protection."

The New England Journal of Medicine study was welcomed by other flu experts.

Dr John Wood, from the National Institute for Biological Standards and Control, a government funded body which helps in the production and testing of vaccines for emerging flu strains, told the BBC: "The fact that they seem to have this protection after eight years is really interesting."

He added: "If governments are thinking about stockpiling vaccine, you could actually be stockpiling it in people's arms."

An influenza pandemic occurs when a new influenza strain emerges (one to which humans have no immunity), mutates and spreads globally as a virus. Although it is not possible to predict the actual pandemic influenza strain, global health authorities have identified H5N1 avian influenza as a strain with the greatest pandemic potential in humans. 3

H5N1 is currently circulating in birds and has caused serious illness in more than 380 people worldwide with a mortality rate, among people known to have been infected, of greater than 60 percent. 4.

The purpose of pre-pandemic vaccination is to prime the immune system to better defend against infections from an H5N1 influenza virus and is intended for use before the World Health Organization (WHO) declares an influenza pandemic.

MF59 is used in a vaccine against seasonal flu specially designed for older people who have weaker immune systems so do not respond so well to traditional vaccines, although this particular vaccine is not currently available in the UK. More than 40 million doses have been distributed worldwide since 1997. 5

References

1 Jennings LC et al. Stockpiling prepandemic influenza vaccines: a new cornerstone of pandemic preparedness plans. Lancet Infectious Diseases 2008; 8: 650-658

2. Stephenson I et al. Antigenically distinct MF59-adjuvanted vaccine to boost immunity to H5N1. New England Journal of Medicine 2008; October 9: 1631-1633

3. World Health Organization Avian influenza H5N1 infection in humans, WHO Web site: http://www.who.int/csr/don/2004_01_22/en/index.html, accessed August 22, 2008

4. World Health Organization Cumulative Number of Confirmed Human Cases of Avian Influenza, WHO Web site, accessed August 19, 2008

5. Company data on file.

Source

Zarina Baloch
Public Relations Department
Novartis Vaccines and Diagnostics UK
Frimley Business Park
Frimley, Camberley, Surrey GU16 7SR
United Kingdom
http://www.novartis.com

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