Vaccines: Need and Opportunity
Inventions reached their limit a long time ago, and I see no hope for further development.
—Julius Sextus Frontius (40–103)
Eradication and reservoirs
The reader who worked their way through Chapter 1 will now be familiar, albeit superficially, with the context and history of vaccines, vaccination, and vaccinology. More than 80 infectious agents are known to be regularly pathogenic in humans; of these there are now more than 30 licensed individual vaccines targeting 26 infectious diseases, most of which are either viral or bacterial in nature. About half of these 30 vaccines are in common use and are, in the main, employed to prevent childhood infections. The lasting effects of vaccination work to greatly reduce the morbidity and mortality of disease, often conferring lifetime protection.
Smallpox elimination was a remarkable and – regrettably – a unique phenomenon necessitating an unprecedented, and seldom repeated, level of international cooperation. The campaign was effective because of three factors which, when combined with effective multinational surveillance and public education, made eradication feasible. First, an effective vaccine was made readily available on a large scale, and technical problems with transport and storage were solved. Second, since variola virus produces an acute illness, disease is relatively easy to identify and to differentiate from other infections. Moreover, there is no chronic carrier stage. Thirdly, the only reservoir ...