Elementary knowledge of vaccines:
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.
Vaccines may be constructed in several ways:
- 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).
| Type of vaccines | Examples |
| Live-attenuated | Measles, Mumps, Rubella, Varicella zoster |
| Inactivated | Hepatitis A, Influenza, Pneumococcal polysaccharide |
| Recombinant sub-unit | Hepatitis B |
| Toxoid | Tetanus, Diphtheria |
| Conjugate polysaccharide-protein | Pneumococcal, meningococcal, Haemophlius influenzea type b (Hib) |
TABLE :. EXAMPLES OF VACCINES BY TYPE
| Vaccine-preventable disease | Type of disease | Type of vaccine | Year vaccine developed | Most common severe disease outcomes | ||||
| Smallpox | viral | live attenuated | 1798 | disfiguring, sometimes fatal | ||||
| Rabies | viral | Inactivated, inactivated (cell culture) | 1885 | always fatal | ||||
| Typhoid | bacterial | inactivated intestinal
live attenuated polysaccharide protein conjugate |
1886
1983 1994 2008 |
intestinal haemorrhage and perforations, encephalitis, psychosis, abscesses of internal organs, sometimes fatal | ||||
| Cholera | bacterial | inactivated (injectable) inactivated and recombinant protein (oral) inactivated (oral) | 1896
1991 1997 |
life- threatening dehydration, electrolyte imbalance, sometimes fatal | ||||
| Plague | bacterial | inactivated | 1897 | seizures, coma, internal bleeding, fatal within four days if not threate. | ||||
| Diphtheria | bacterial | Toxoid | 1923 | choking, heart and kidney failure, facial or swallowing or respiratory paralysis, sometimes fata | ||||
| Tetanus | bacterial | Toxoid | 1926 | severe muscle spasms and bone fractures, lockjaw, respiratory distress, sometimes fatal | ||||
| Pertussis | bacterial | inactivated purified protein* | 1914
1981 |
choking in young infants, rib fractures, hernias, incontinence, ruptured blood vessels, sometimes fatal | ||||
| Tuberculosis | bacterial | live attenuated | 1921 | coughing blood, abscesses of internal organs or bone, meningitis, sometimes fatal | ||||
| Yellow fever | viral | live attenuated | 1932 | liver damage, internal bleeding, sometimes fatal | ||||
| Influenza | viral | inactivated
live attenuated |
1936
2003 |
life-threatening pneumonia, worsening of coronary heart disease, extreme muscular fatigue or aches, high fever, sometimes fatal | ||||
| Polio | viral | inactivated
live attenuated |
2003
1955 |
respiratory paralysis, life-long paralysis of limb(s), skeletal deformity, sometimes fatal | ||||
| Pneumococcal | bacterial | 23-valent polysaccharide;
protein conjugate |
1983
2000 |
pneumonia, meningitis, ear infections, infections of bone and heart muscle, protein conjugate sometimes fatal | ||||
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Chief Mentor at Oracle IAS
Hemant Bhatt is a B. Tech from Pantnagar University and has studied Social Sciences at SciencesPo, Paris. He teaches at Oracle IAS, Dehradun. He has given 5 UPSC mains back to back along with 2 interviews.
He is a bibliophile,accomplished writer and a fitness enthusiast.
He is a bibliophile,accomplished writer and a fitness enthusiast.
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