Vaccines for the twenty-first century society

Abstract

Vaccines have been one of the major revolutions in the history of mankind and, during the twentieth century, they eliminated most of the childhood diseases that used to cause millions of deaths. In the twenty-first century, vaccines will also play a major part in safeguarding people's health. Supported by the innovations derived from new technologies, vaccines will address the new needs of a twenty-first century society characterized by increased life expectancy, emerging infections and poverty in low-income countries.

Figure 1. Increase in life expectancy.

The graph shows the increase in life expectancy that occurred in the countries with longest lifespans^,, from 1750 to the present day and also the projected increase in longevity for this century. The average life expectancy for individuals in the society for which most vaccines were developed was 60–65 years. This society was characterized by a high proportion of children and young people, and is quite different from today's society, which is characterized by a high proportion of elderly people and a life expectancy of more than 80 years.

Figure 2. Target population for vaccines in the twenty-first century.

a | The most important vaccines for each age group are reported. b | Special target groups for vaccination in the twenty-first century. The most important vaccines for each target group are reported. The lists of vaccines reported are indicative and they are not intended to be exhaustive. C. difficile, Clostridium difficile; E. coli, Escherichia coli; EV71, enterovirus 71; H. influenzae, Haemophilus influenzae; K. pneumoniae, Klebsiella pneumoniae; P. aeruginosa, Pseudomonas aeruginosa; S. aureus, Staphylococcus aureus; SARS, severe acute respiratory syndrome.

Figure 3. Technologies for vaccine development.

Since the times of Pasteur, vaccines have been developed using empirical approaches consisting mostly of killed or live-attenuated microorganisms, partially purified components of pathogens (subunit vaccines), detoxified toxins or polysaccharides. These vaccines have been very successful in eliminating many devastating diseases. During the past 30 years, subsequent waves of new technologies have made possible vaccines that were impossible with the empirical approaches. These include recombinant DNA technology, glycoconjugation, reverse vaccinology and many emerging next-generation technologies, such as novel adjuvants, synthetic biology and structure-based vaccine design (structural vaccinology), that promise a very successful future for vaccines. BCG, bacille Calmette–Guérin; C. difficile, Clostridium difficile; E. coli, Escherichia coli; H. influenzae, Haemophilus influenzae; MMRV, measles, mumps, rubella, varicella; S. aureus, Staphylococcus aureus.