Vaccine development at the turn of the twentyfirst century

Just as the end of the nineteenth century marked the start of a new era of prevention through the invention and development of vaccines, so too did the end of the twentieth century. Advances and new discoveries in recombinant and conjugate technologies have made possible the development of vaccines against diseases such as hepatitis B, and Haemophilus influenzae type b, and the creation of additional vaccines against pathogens such as pneumococcus and meningococcus which could provide protection in infancy and perhaps durable, potentially lifelong, immunity (Plotkin and Orenstein, 2004).

Two second-generation rotavirus vaccines are the product of unprecedented multinational field trials that involved well over 100,000 children. Such large-scale trials were required to have the statistical power to detect an association with intussusception and thereby demonstrate the safety of these vaccines.

The development of vaccines which protect against infection with Human Papilloma Virus (HPV) types 16 and 18 can prevent cervical cancers associated with chronic infection by these serotypes. These vaccines have the potential to reduce the most common cause of cancer mortality among women worldwide. However, to realize the enormous promise of these new vaccines, two formidable challenges must be overcome: adolescent girls must be immunized prior to the onset of sexual activity, and this vaccine must be made widely available throughout the world.

These advances were the product of more complex and expensive vaccine development, which raised new challenges in the financing, distribution, and availability of vaccines; these will be discussed in more detail below. With more than 400 new vaccine projects currently underway around the world, the twenty-first century also looks to be a time of great achievement (Levine, 2004).

Year

Note: Vaccine series considered for children through age six years. All costs are in 2001 US dollai

Figure 10.7 Cumulative cost of recommended vaccine series per child at public-sector prices, 1975-2001. Source: Davis etal. (2002).

Year

Note: Vaccine series considered for children through age six years. All costs are in 2001 US dollai

Figure 10.7 Cumulative cost of recommended vaccine series per child at public-sector prices, 1975-2001. Source: Davis etal. (2002).

The making of vaccines has historically been a unique public-private partnership involving an interdependent collaboration of government, industry, and academia in vaccine research, design, and development (NVAC, 1997). Since the latter part of the twentieth century, the costs of vaccine development and manufacture have risen sharply. The use of more complex and expensive technologies to develop vaccines, the increase in regulatory and licensing requirements, and the proliferation of legal issues relevant to vaccine manufacture, distribution, and use have all contributed to this rise in cost (see Figure 10.7).

These costs, the relatively smaller return on investment realized by vaccines versus other pharmaceuticals, and the misalignment of need/disease burden versus potential lucrative markets, has resulted in a diminution in the number of vaccine manufacturers in the developed world, and a more tenuous vaccine supply.

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