Prevention of disease by vaccination, is beyond any doubt, is most significant achievement of mankind in the field of healthcare management. The companies that comprise the vaccine industry are involved in research and development of new vaccine candidate, manufacture, sales and distribution of same. In 2013, worldwide sale of vaccine was $25 bn and was expected to grow by $35 bn by 2020. By 2019 global estimate for vaccine was 5.5 billion doses. Vaccine currently prevents 3 million death per year and positive contribution to economy is more than billion dollar per year. Eradication of small pox is attributed to vaccination. Other disease such as polio is expected to eradicate sooner in future. There is hurdle for immunizing healthy population and a perception of modest return in investment in vaccine production, have presented a barrier for pharmaceutical companies to invest in vaccine manufacturing. But the landscape is now changing, recently some of the vaccines are expected to achieve blockbuster status (>1-billion-dollar annual sale for Prevnar (Wayeth Pharmaceuticals) for pneumococcal disease), and Gardasil (Merck) for human papillomavirus (HPV) infection.
History of vaccination goes 200 years ago, with introduction of small pox vaccine. In last 25 years, half of new vaccine has been introduced, approximately one vaccine per year compare to one in five years before that.
Source: cancercenter.com
Vaccine Development:
1. Process Development: To satisfy regulatory requirements for clinical testing including clinical lots, preclinical toxicology testing, and analytical assessment, and finally, scale-up methods that lead to a consistent manufacturing process at one-tenth of full-scale process developed involving making preparations of the test vaccine. Three consecutive lots are tested to test immunogenicity. To test the purity of raw materials, stability and potency of the vaccine product, and immunologic and other criteria to predict vaccine efficacy, specific methods are developed for assay.
2. Clinical Development: Phase I trial: To establish early safety and immunogenicity in small group
Phase II trial: To establish safety, dose ranging and immunogenicity in 200-400 individuals. Phase IIb trial: Proof of concept trials for efficacy. Phase III trials: Safety and efficacy study in thousands subject, to get licensure. Phase IV trial: Post licensure studies of safety and efficacy.
Vaccine development has following stage:
i) Acceptance of a Vaccine candidate from basic research laboratory (Phase I and Phase IIa trials)
ii) Product Definition includes, method of synthesis bioprocess steps number of component stability and formulation (Phase IIb trials).
iii) Define the clinical dose and appropriate manufacturing scale. It involves identification, manufacturing, filling and release of clinical grade vaccine (Phase III study). Complete technological transfer to final site of manufacture of full-scale lot.
iv) Completion of Phase III pivotal clinical studies.
New Vaccine technology:
1. Gene Based vaccine: Gene-based vaccines consisting of plasmid DNA or recombinant viral vector have ability to elicit cellular immunity. Plasmid DNA vaccines are produced in E. coli using standard fermentation and downstream processing
2. VLP’s: VLP’s are particle-based vaccine which gets internalized and processed by APC (Antigen processing cell) eliciting the cellular immunity particularly CTL (Cytotoxic T cell) response
3. Plant Derived Vaccine: Transgenic plants such as potato, tomato and banana expressing vaccine antigens could be grown at agricultural scale to yield ready-to-eat vaccines without the need for complex and costly manufacturing procedures and facilities
Article by
Kamini Singh
BioPsych Bioscience
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