How quickly will Influenza A (H1N1) vaccines be available?

The first doses of Influenza A (H1N1) vaccine could be available in five to six months from identification of the pandemic strain. The regulatory approval will be conducted in parallel with the manufacturing process. Regulatory authorities have put into place expedited processes that do not compromise on the quality and safety of the vaccine. Delays in production could result from poor growth of the virus strain used to make the vaccine.

How would manufacturers be selected?

There are currently more than a dozen vaccine manufacturers with licenses to produce influenza vaccines. The vaccine strain will be available to each of them for vaccine production.

What is the global manufacturing capacity for a potential Influenza A (H1N1) pandemic vaccine?

While this cannot be assessed precisely since there is much uncertainty regarding the appropriate formulation for an effective and protective vaccine, a conservative estimate of global capacity is at least 1 to 2 billion doses per year.

How is production capacity for influenza vaccines distributed geographically?

More that 90% of the global capacity today is located in Europe and in North America. However, during the past five years, other regions have begun to acquire the technology to produce influenza vaccines. Six manufacturers in developing countries have done so with technical and financial support from WHO.

What will be the storage requirements for Influenza A (H1N1) vaccine?

The vaccine should be stored under refrigerated conditions at between 2°C and 8°C.

It has been impossible so far to develop vaccines for major killers such as HIV and malaria. How sure are we that there will not be scientific or other hurdles in developing an effective Influenza A (H1N1) vaccine?

Typically, development of influenza vaccines has not posed a problem. Influenza vaccines have been used in humans for many years and are known to be immunogenic and effective. Each year seasonal influenza vaccines with varying composition are produced for the northern and southern hemisphere influenza seasons. Vaccine manufacturers will employ a number of different technologies to develop their vaccines. They will take advantage, notably, of novel approaches that were developed over the past years for H5N1 avian influenza vaccines. One key unknown is yield of vaccine virus production, since some strains grow better than others and the behavior of the new Influenza A (H1N1) strain in manufacturers’ systems is not yet known. New recombinant technologies are under development, but have not yet been approved for use.

Will Influenza A (H1N1) vaccines be effective in all population groups?

There are not data on this but there also is no reason to expect that they would not, given current information.

Will the Influenza A (H1N1) vaccine be safe?

Licensed vaccines are held to a very high standard of safety. All possible precautions will be taken to ensure safety and new Influenza A (H1N1) vaccines.

How can a repeat of the 1976 swine flu vaccine complications (Guillain-Barré syndrome) experienced in the United States of America be avoided?

Guillain-Barré syndrome is an acute disorder of the nervous system. It is observed following a variety of infections, including influenza. Studies suggest that regular seasonal influenza vaccines could be associated with an increased risk of Guillain-Barré syndrome on the order of one to two cases per million vaccinated persons. During the 1976 influenza vaccination campaign, this risk increased to around 10 cases per million vaccinated persons which led to the withdrawal of the vaccine.

Pandemic vaccines will be manufactured according to established standards. However, they are new products so there is an inherent risk that they will cause slightly differently reactions in humans. Close monitoring and investigation of all serious adverse events following administration of vaccine is essential. The systems for monitoring safety are an integral part of the strategies for the implementation of the new pandemic influenza vaccines. Quality control for the production of influenza vaccines has improved substantially since the 1970s.

Will it be possible to deliver new Influenza A (H1N1) vaccine simultaneously with other vaccines?

Inactivated influenza vaccine can be given at the same time as other injectable vaccines, but the vaccines should be administered at different injection sites.