The genes of viruses causing human, avian and swine influenza constantly become mixed in regions where all three species are in close contact, such as in the Far East. As a result, the influenza virus can mutate, which means the population has little or no immunity to it, and the virus can quickly spread to several continents and cause a severe influenza. The World Health Organization WHO, which monitors the global influenza situation, can then warn of an impending pandemic.
Developing a vaccine for a pandemic is challenging due to lack of time: it often takes only a few months from the identification of risk to pandemic outbreak. Standard development programmes are too slow to develop a vaccine in that time. To solve this problem, the mock-up procedure was introduced.
A mock-up vaccine refers to a model of the pandemic influenza vaccine, but it contains a different strain of viruses than the actual vaccine. The standard procedure is followed to ensure the quality, immunogenicity and safety of the mock-up vaccine well in time before the outbreak of a pandemic, but the vaccine is not launched to the market. If a pandemic breaks out, the actual virus strain causing it will be included in the mock-up vaccine, and the actual vaccine can be produced in a very short time.
The scope of the study programme for a strain-specific vaccine is limited, and its objective is to prove acceptable quality and safety in relatively small studies. At this point, there is no time to study the efficacy, but the immune response generated by the vaccine can be measured and preliminary conclusions regarding efficacy can be made. If a pandemic breaks out, demand for a vaccine will exceed production capacity. To address this problem, some pandemic vaccines are prepared with a smaller quantity of the virus antigen than would normally be used. These vaccine comes with an adjuvant designed to enhance the immune response. When a strain-specific vaccine is needed, development and regulatory processing should be completed in just 4–6 months. Studies on the efficacy and immunogenicity of the vaccine will continue after the vaccines are available on the market.
Besides pharmacies and hospitals, the Government stocks antiviral medication suitable for influenza treatment in its reserve supplies.
Fimea's duties in a pandemic
When preparing for a pandemic, Fimea's duties include:
- planning the supply of medicines from the Government reserve,
- preparing instructions for distribution and use for the medicinal products, and
- overseeing the marketing of medicines intended for the prevention and treatment of the pandemic virus, and preventing trade in counterfeit medicines.
During a pandemic, Fimea is required:
- to publish instructions for the use of antiviral medication on its website,
- to monitor the availability and use of medicines in co-operation with the National Institute for Health and Welfare,
- to monitor adverse drug reactions (the National Institute for Health and Welfare is responsible for monitoring the adverse effects of vaccines), and
- to provide instructions to interested parties on procedures to be followed (e.g. instructions to marketing authorisation holders on adverse effect monitoring procedures in a pandemic).