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Summary
In traditional vaccination the whole disease-causing organism, or part of a it is given to a host to stimulate an immune response and protect against subsequent infection. In DNA vaccination a piece of DNA encoding a part of the organism is given to the host in a form that can be read by it’s own cells. The host then produces the vaccine protein internally.
DNA vaccination is a relatively new alternative to traditional vaccines. DNA vaccination has several advantages over more traditional forms of vaccination. Generally, DNA vaccines are cheaper and easier to produce than other vaccines and similar production techniques can be used for multiple vaccines. Because the DNA used is stringently designed and otherwise inert in host cells, DNA vaccines should be safer than most traditional vaccines. Also only relatively tiny amounts of vaccine protein are actually produced, reducing the chance of adverse reactions.
Although research into DNA vaccines has been progressing for a number of years, results in large mammals (such as humans) have been poor, with little or no protection generally being afforded. Various modifications to the standard delivery method have been tested or are currently in testing. The potential of DNA vaccines does however mean that a great deal of research is still ongoing in this field. The only commercial DNA vaccine currently available is Apex-IHN for prevention of infectious heamatopoietic necrosis virus in farmed fish.
Although vaccination has had many well-documented success stories, there is still a pressing need for the development of new vaccines. Even with diseases where a reliable vaccine is available, distribution and costs issues mean that vaccines are not always used where they are needed, as highlighted by the distribution of hepatitis B cases world-wide. There is therefore a need for cheaper, more stable vaccines.
Preparation of traditional vaccines against new and emerging threats, or new variants of current diseases can be lengthy. This problem has been highlighted recently with the threat of a pandemic H5N1 influenza outbreak. Influenza (pictured left) could spread so rapidly that our ability to produce a vaccine against a new variant would be outstripped. If this variant were highly pathogenic, the death total could be potentially huge. The ability to produce new vaccines rapidly could potentially be of great use in combating such outbreaks. In the case of influenza, there is also the potential to reduce the lag time which is currently a factor in producing the annual seasonal vaccines. An ability to rapidly produce vaccine could also have applications in protecting against potential bioterrorist threats.