New Vaccine Technology
Research is continuous; therefore, there will always be newer and better advances in vaccine technology, as people strive to make vaccines and medicine better. These vaccine technologies are still in their developing stages, although they will probably be in common use in the near future. These promising technologies could be the near solution to a possible avian flu pandemic.
Cell-based production of vaccine
In late 2005, a research team at the University of Pittsburgh succeeded in quickly making an effective vaccine against avian flu in animals that could be produced using cells grown in the laboratory, not chicken eggs.
The team used the hemagglutinin sequence of an avian flu virus, and inserted it in an adenovirus (a cold virus), causing the adenovirus to make hemagglutinin proteins to be recognized by the immune system. The modified adenovirus then was grown in cell culture, using bacterial cells, and the viruses were harvested to be used in the vaccine. This whole process of going from a simple sequence coding for a protein to producing a vaccine only took a little more than 30 days.
The vaccine was then tested on chickens and mice. The animals were injected with the vaccine and were later exposed to the avian flu virus. All the animals were protected from getting the disease.
A technique such as this would be ideal for producing vaccines in an avian flu pandemic, because it does not take long to produce the vaccine. People could attain the genetic sequence of the pandemic flu virus and quickly convert it to a vaccine that could stop the disease's spread.
Since the immune system only recognizes and makes antibodies for certain parts of viruses, there are some vaccines that only include these necessary parts, called subunit vaccines.
Subunit vaccines consist of virus proteins that the immune system recognizes, not whole viruses. The immune system only recognizes and makes antibodies for certain proteins on the virus. In the avian flu virus, the protein that is recognized by the immune system is hemagglutinin, so subunit avian flu vaccines only include hemaglutinin.
One of the leaders in developing subunit vaccines for avian flu is the company Protein Sciences. Protein Sciences has developing a vaccine they call Flublok, containing hemagglutinin proteins of avian flu viruses. The vaccine has been undergoing human trials with successful results, and is waiting for market approval in the near future.
Subunit vaccines that are being developed seem to have great advantages over current vaccines. First, subunit vaccines can be produced much faster and safer than making vaccines in eggs. Also, these vaccines do not need potentially harmful preservatives like thimerosal, because the vaccine does not contain viruses, just proteins--so they can be stored in a simple buffered salt water solution.
DNA-based vaccines consist of a segment of viral DNA, made in the laboratory. When it is injected into the body, the artificial DNA is taken up by cells, which translate the DNA into viral proteins. This triggers the immune system to produce antibodies for the viral proteins, therefore also giving the body protection against the virus which the protein came from.
DNA-based vaccines would be a great improvement over current vaccines. DNA is very cheap and fast to produce, therefore solving the slow production problem. Also, a DNA-based vaccine could be given using an air gun, by shooting a tiny, DNA-covered particle under the skin. This would make vaccine easier to distribute, because it would not require much training for someone to use an air gun to administer the vaccine.
DNA-based vaccines for avian flu are not are too far from becoming reality. An experimental DNA-based vaccine for HIV has already been developed and has had good results in trials.