Flu, not an innocent illness...
Flu is an acute infection of the bronchial tubes and is caused by the flu virus. Flu is extremely contagious and makes you feel really ill. In addition, flu can have extremely serious consequences: on average 1,500 people die of flu in Belgium annually. There were even as many as 4,500 flu victims during the winter period of 1989 and 1990. According to the World Health Organization, on average 10 to 20% of the world's population is infected by flu every year. This leads to 3 to 5 million hospitalizations and 250 000 to 500 000 deaths a year.
What makes the influenza virus so special?
The outer coating of the influenza virus changes gradually, making the virus invisible to the antibodies that were built up during an earlier infection or vaccination; after all, these antibodies are aimed at the changeable proteins of the outer coating. Since no one as yet has antibodies, the slightly altered virus can easily set off a new epidemic. Thus far no vaccine has been developed against influenza that lasts for a lifetime, in contrast to diseases as polio, hepatitis B or measles.
Flu, prevention is better...
Vaccination offers the most efficient protection to flu. The present flu vaccines are a mixture of three vaccines, each offering protection to a certain virus strain. Vaccination reduces death and the amount of hospitalizations as a result of flu considerably. The government strongly advises flu vaccination for those over 60 years old, diabetes patients, people with diminished resistance or chronic kidney, heart and lung disorders. However, everyone can consider vaccination: it will give you 80% less chance of getting the flu next winter.
No more annual renewal thanks to new research?
VIB and the British company Acambis are collaborating on the development of a universal flu vaccine that offers protection to all flu variants. Moreover, the vaccine would not require annual adaptations to the virus changes. This is because the candidate vaccine uses the M2e-domain. This domain is strongly conserved, and nearly identical in all human virus strains, also those that caused the pandemics in the previous century. As a consequence, people can be vaccinated long before a new pandemic breaks out.
This innovative vaccine is currently in a preclinical phase. It is not longer produced by the growth of viruses, but the active component is produced in bacteria. Therefore the production process will be more effective, safer and cheaper.
Walter Fiers, co-inventor (UGent and VIB):
'The structure of M2e is almost identical in all known flu viruses that can be transmitted between people. We indicated that the M2e vaccine offers full protection to flu without side effects in mice. This way vaccination against all human flu viruses is possible, not only against viruses returning yearly, but even against future epidemics. Through our cooperation with Acambis we can continue the development of this promising vaccine.'
Cooperation between VIB and Acambis
Professor Walter Fiers and his team carried out the research on which the collaboration between VIB and Acambis is based. Acambis recently acquired an influenza A vaccine candidate from Apovia, a US company. Apovia had originally obtained the necessary technology for the development of the vaccine from VIB. Through the research collaboration with VIB, together with internal research, Acambis enters the flu vaccine market, one of the most significant vaccine markets.
Gordon Cameron, CEO (Acambis):
'This programme gives Acambis the opportunity to enter one of the most significant vaccine markets - influenza. The recent influenza vaccine shortages have highlighted the inadequacies of current influenza vaccines and their manufacturing methods. Through the collaboration with VIB we get the chance to develop the ultimate vaccine that will offer protection against all flu virus variants and reduce the annual redesign of the vaccine.'
How do influenza vaccines work?
Each year the World Health Organization determines which three influenza viruses are the most likely to cause an influenza epidemic during the next winter period. These candidates are used for the production of a vaccine. These days influenza vaccines are prepared by growing viruses on chicken embryos or in cultures of animal cells. Then proteins originating from the outer coating of the virus are purified from the harvested viruses and used as vaccine. After inoculation, the human immune system creates antibodies. After a few weeks, sufficient antibodies have been produced and will neutralize the viruses in case of an infection. Since new species of viruses that have slightly altered proteins on their outer coatings appear nearly every year, injection must be repeated every year.
Pandemics, a tremendous threat
A new human influenza virus in which the outer coating is drastically altered appears a few times every century. This new virus spreads lightning-fast around the entire world, since no one has yet been able to build up antibodies against it. Such a worldwide epidemic or pandemic can contaminate up to 50% or more of the world population. In the last century there was the Asian flu, the Hong Kong flu and above all the Spanish flu. During the period between 1917 and 1920 the latter was responsible for over 50 million victims.
Pandemic viruses occur when the genetic material originating from a fowl plague virus is mixed with that of a human influenza virus. This is why the World Health Organization has followed the recent epidemics caused by the fowl plague virus of the type H5N1 in the Far East with an extremely watchful eye.
The virus species that will cause the next pandemic is not known, so no vaccine can be produced against it in advance. Only after a pandemic has burst into action, the responsible virus can be identified and a suitable vaccine can be developed. It will take some 6 to 9 months before the vaccine is ready for use. 'Optimistic' predictions speak of two million deaths worldwide and 20,000 deaths in Belgium.