Question

speech on vacation (150 - 200 word limit) ​

Answer 1

The word “vaccine” originates from the Latin Variolae vaccinae

(cowpox), which Edward Jenner demonstrated in 1798 could

prevent smallpox in humans. Today the term ‘vaccine’ applies

to all biological preparations, produced from living organisms,

that enhance immunity against disease and either prevent

(prophylactic vaccines) or, in some cases, treat disease

(therapeutic vaccines). Vaccines are administered in liquid

form, either by injection, by oral, or by intranasal routes.

Vaccines are composed of either the entire disease-causing

microorganism or some of its components. They may be

constructed in several ways (See Figure 1):

• From living organisms that have been weakened, usually

from cultivation under sub-optimal conditions (also called

attenuation), or from genetic modification, which has the

effect of reducing their ability to cause disease;

• From whole organisms that have been inactivated by

chemical, thermal or other means;

• From components of the disease-causing organism, such

as specific proteins and polysaccharides, or nucleic acids;

• From inactivated toxins of toxin-producing bacteria;

• From the linkage (conjugation) of polysaccharides

to proteins (this increases the effectiveness of

polysaccharide vaccines in young children) (See Figure 2).

Examples of each type of vaccine are shown in Table 1.