With the current outbreak of swine flu in our neighbor country, questions have been raised about the availability and feasibility of new vaccines. Vaccines are pharmaceutical products that deliver or generate antigens that induce specific, active and protective immunity against infectious diseases. Throughout the history of medicine, vaccines have eradicated smallpox, polio (almost) and put measles, mumps, diphteria, rubella, tetanus, etc. under control. Vaccines have undergone numerous changes from the first generation (whole-organism attenuated or killed organisms) to the second generation (purified antigens such as polysaccharides, toxoids or proteins but no intact organisms) and now the third generation (DNA vaccines albeit many are still in developmental stages).

Vaccines are undoubtedly effective but then why there is no vaccine for pandemic-potential viral diseases such as SARS, avian influenza and now, swine flu? The answer is the lengthy process of R&D development and approval of a vaccine. Indeed, under the 2002 “Animal Rule”, the FDA’s Center for Biologics Evaluation and Research (CBER) will approve a vaccine for marketing solely on evidence of safety and efficacy derived from animal models and human clinical trials for safety and immunogenicity. Vaccine manufacturers (top four companies are: Sanofi-Pasteur, Merck, GSK, and Wyeth) must follow strict cGMP (clinical Good Manufacture Practice) regulations and all clinical trials must be conducted according to Good Clinical Practices (GCPs). Data must be collected from three clinical stages (Phases I, II and III) prior to submission of a Biologics License Application (BLA), which is a petition equivalent to a New Drug Application (NDA) for drugs. After Phase III, CBER may seek a hearing with an Advisory Panel (non-FDA experts) that advises FDA on the vaccine’s merits. Finally, the Phase IV post-marketing since many vaccines are developed without directly challenging a test subject with the pathogen. Consequently, from the initial stage of development to getting an approval from the FDA for commercialization requires a development timeline of approximately 15-25 years. Although effective, vaccine will remain the stepchild of the pharmaceutical industry due to the lengthy process of approval, the low profitability but very high liability issues. It is unlikely to have a swine flu vaccine to respond to the current outbreak from Mexico. Meanwhile, stay away from cháo lòng, tiết canh heo, dồi huyết, lòng lợn luộc chấm mắm tôm, etc. Talking about "lòng lợn", hey guys, it's not a good time to go to Tijuana now. Stay home and,

Until the next time, stay healthy
Tiến sĩ Bùi quốc Quang

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