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Rabies vaccine is a vaccine used to control rabies. Rabies can be prevented by vaccination, both in humans and other animals. It is unusual in that it is effective even when injected after infection by the virus, which usually is noticed.
The human diploid cell rabies vaccine (H.D.C.V.) was started in 1967. Human diploid cell rabies vaccines are inactivated vaccines made using the attenuated Pitman-Moore L503 strain of the virus. Human diploid cell rabies vaccines have been given to more than 1.5 million people as of 2006.
Aside from vaccinating humans, another approach was also developed by vaccinating dogs to prevent the spread of the virus. In 1979 the Van Houweling Research Laboratory of the Silliman University Medical Center in Dumaguete in the Philippines, then headed by Dr. George Beran, developed and produced a dog vaccine that gave a three-year immunity from rabies. The development of the vaccine resulted in the elimination of rabies in many parts of the Visayas and Mindanao Islands. The successful program in the Philippines was later used as a model by other countries, such as Ecuador and the Yucatan State of Mexico, in their fight against rabies conducted in collaboration with the World Health Organization.
In addition to these developments, newer and less expensive purified chicken embryo cell vaccine, and purified Vero cell rabies vaccine are now available. The purified Vero cell rabies vaccine uses the attenuated Wistar strain of the rabies virus, and uses the Vero cell line as its host.
Recombinant rabies vaccine (V-RG)
In 1984 researchers at the Wistar Institute developed a recombinant vaccine called V-RG by inserting the glycoprotein gene from rabies into a vaccinia virus. The V-RG vaccine has since been commercialised by Merial under the trademark Raboral. It is harmless to humans and has been shown to be safe for various species of animals that might accidentally encounter it in the wild, including birds (gulls, hawks, and owls).
V-RG has been successfully used in the field in Belgium, France, Germany and the United States to prevent outbreaks of rabies in wildlife. The vaccine is stable under relatively high temperatures and can be delivered orally, making mass vaccination of wildlife possible by putting it in baits. The plan for immunization of normal populations involves dropping bait containing food wrapped around a small dose of the live virus[clarification needed]. The bait would be dropped by helicopter concentrating on areas that have not been infected yet. Such a strategy of oral immunization of foxes in Europe has already achieved substantial reductions in the incidence of human rabies. In November 2008, Germany had been free of new cases for two years and is therefore currently believed to be rabies-free, together with few other countries. A strategy of vaccinating “neighborhood dogs” in Jaipur, India, combined with a sterilization program, has also resulted in a large reduction in the number of human cases.
Duration of immunity
The duration of immunity afforded to humans by a two injection vaccination course was found to be between two to three years. Following administration of a booster dose (recommended at one year), one study found 97% of immuno-competent individuals demonstrate protective levels of neutralizing antibodies at 10 years.
Currently, pre-exposure immunization has been used on domesticated and normal non-human populations. In many jurisdictions, domestic dogs, cats, ferrets, and rabbits are required to be vaccinated
Imrab is an example of a veterinary rabies vaccine containing the Pasteur strain of killed rabies virus. Several different types of Imrab exist, including Imrab, Imrab 3, and Imrab Large Animal. Imrab 3 has been approved for ferrets and, in some areas, pet skunks.
Oral vaccination against rabies is a preventive measure to eradicate rabies in wild animals, vectors of disease, mainly foxes and rareraccoons, raccoon dogs, coyotes and jackals, but also can be used for dogs in developing countries.
Baits used for oral vaccination are made of fishmeal or dog food and contains a vaccine packet with V-RG, a recombinant vaccine made from a living pox virus vector, vaccinia, that carries the rabies antigen in the form of rabies glycoprotein. When animals eat through the outer bait matrix, the inner sachet gets punctured allowing vaccine to enter the animal’s mouth and coat the lymphatic tissue in the throat. There is an immune response to the rabies antigen which creates antibodies for rabies.
Baits are distributed by airplanes in rural areas and by hand in urban and suburban areas. The idea of wildlife vaccination was conceived during the 1960s, and modified-live rabies viruses were used for the experimental oral vaccination of carnivores by the 1970s. The development of safe and effective rabies virus vaccines applied in attractive baits resulted in the first field trials in Switzerland in 1978.
Virtually every infection with rabies resulted in death, until two French scientists, Louis Pasteur and Émile Roux, developed the first rabies vaccination in 1885. This vaccine was first used on a human on July 6, 1885, on nine-year-old Joseph Meister (1876–1940), who had been mauled by a rabid dog.
Their vaccine consisted of a sample of the virus harvested from infected (and necessarily dead) rabbits, which was weakened by allowing it to dry for 5 to 10 days. Similar nerve tissue-derived vaccines are still used now in some countries, and while they are much cheaper than modern cell culture vaccines, they are not as effective. Neural tissue vaccines also carry a certain risk of neurological complications.
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