Friday, 14 December 2007
Injections set to become passe
By Syed Akbar
Seoul, Dec 13: Painful injections for immunisation will soon become a thing of the past thanks to a pioneering research by the International Vaccine Institute here.
Vaccine drops can be simply put below one's tongue (sub-lingual) to prevent diseases of the lungs and the stomach. Vaccination through the mucus of the tongue is far more effective, cheaper and painless. Studies by IVI showed that the sub-lingual method of immunisation was better than oral or nasal administration.
"Since many people are afraid of injections, we are working on the methods to deliver vaccines for pneumococcal (lung) diseases and those of the enteric (digestive system) through the mucus of the tongue. Just put a drop and it starts working immediately without any side effects. Our results on mice have been successful and we are in the clinical trial stage II. It will be available in the market soon," Dr Konrad Stadler, senior scientist of International Vaccine Institute, told this correspondent.
Scientists in the IVI's virology section examined the potential of sublingual delivery of vaccine in mice. The study showed the existence of a dense network of dendritic cells in the epithelium and a rapid and transient increase in the frequency of dendrite cells after topical application of cholera toxin adjuvant under the tongue. "Sub-lingual immunization was comparable to intranasal immunization and was superior to oral immunization regarding the magnitude and anatomic dissemination of the induced immune responses," he said.
Moreover, sub-lingual administration of live influenza virus at a dose lethal by the nasal route was well tolerated and did not redirect virus to the olfactory (nose) bulb. These features underscore the potential of the sub-lingual mucosa to serve as an alternative vaccine delivery route.
The results of the IVI's study were presented on the occasion of the first symposium on pneumococcal vaccination in Asia-Pacific region that began in this South Korean Capital city on Thursday. Leading experts, policymakers, decision-makers, and opinion leaders from more than 20 countries from the Asia-Pacific Region have proposed solutions to fight against childhood pneumonia, considered the first cause of children's deaths in developing countries around the world.
Among all child deaths associated with pneumonia, 50 per cent are associated with the bacterium *Streptococcus pneumoniae* which is believed to cause seven lakh to 10 lakh deaths annually among children less than five years of age.
"Pneumococcal conjugate vaccines capable of protecting against seven of the most common serotypes of this organism are currently available for introduction into routine infant immunization programs. These vaccines could potentially save about half a million lives every year. India is one of the top five Asian countries where the burden of pneumococcal disease is quite high," said Dr Luis Jodar, IVI deputy director-general.
The sub-lingual vaccine will be delivered using a polymer which is capableof gelling in-situ in contact with body fluids, including the oral fluid. It adheres to the mucus and stays in the tongue region for a long time with a sustained antigen release. In addition, the polymer has an antigen stabilization effect. The formulation can be prepared in various forms - a liquid, a soft gel, a powder, or a dried pad.
Sublingual technology would allow for needle-free self-administration of the vaccines which should significantly reduce the number of trained professionals typically required for large immunization programs. Also there's no need for cold storage and thus can be transported to even the remotest places. The dosage will also come down by 10 to 100 times, reducing the risk of reaction to drug.
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