Science & Technology in Action

16th Edition

How to eliminate a viral disease

Health Service Executive

Jnr Science Cert
Elimination of an infectious disease means reducing the incidence of the disease to zero in a defined geographical area, through deliberate efforts. This requires ongoing measures to prevent infection from outside and to prevent the spread of any infection that does occur. Eradication refers to the permanent reduction to zero of the worldwide incidence of an infection.

Available downloads

The full lessons along with a supporting toolkit are available in three different formats, A4, A3 and as a Powerpoint deck.

Lesson excerpt

Every year vaccination saves millions of people from vaccine preventable diseases, preventing illness, death and disability. The World Health Organisation (WHO) states that a comprehensive vaccination programme is a cornerstone of good public health in any country. Through vaccination it is possible to eliminate and, in some cases, eradicate serious viral diseases. Because of vaccination, smallpox has been eradicated from the world, and measles has been eliminated from many regions of the world.

Elimination and eradication of disease

Eradication and elimination of infectious diseases are defined as follows:
    • Elimination of infectious disease: Reduction to zero of the incidence of a specified disease in a defined geographical area as a result of deliberate efforts; continued intervention measures are required. Example: measles, polio.
    • Eradication: Permanent reduction to zero of the worldwide incidence of infection caused by a specific agent as a result of deliberate efforts; intervention measures are no longer needed. Example: smallpox.

Disease eradication

Ideally if a virus causes disease in humans only, an effective safe vaccine should be able to eradicate the disease. If a human vaccine preventable disease is eradicated, no environmental reservoir of the viral pathogen will then exist. An eradicated pathogen cannot reemerge allowing vaccination to be discontinued. Smallpox is the only disease of humans that has been eradicated by vaccination. Smallpox was a devastating disease known since antiquity caused by the variola virus. On average, 3 out of every 10 people who developed the infection died. The first ‘vaccination’ against smallpox was developed in 1796 by Edward Jenner. In 1863 vaccination against smallpox was made compulsory for all children born in Ireland. Deaths caused by smallpox began to fall, until the last death from smallpox in Ireland was reported in 1907. However, more than 300 million people died from smallpox in the 20th century.

True or False?

  1. An infectious disease is one that can spread from person to person. true
  2. All diseases are infectious. false
  3. Over 25% of all deaths worldwide are due to infectious diseases – i.e. about 15 million deaths every year. true
  4. Infectious diseases are caused by bacteria. false
  5. Viruses reproduce by simple cell division. false
  6. Many infectious diseases are caused by viruses. true
  7. Viruses are easily seen with an optical microscope. false
  8. The best protection against a viral disease is through immunisation. true
  9. Vaccination triggers the body’s immune system to produce antibodies against a particular pathogen. true
  10. Only one human disease has ever been completely eradicated. true
  11. Measles is a highly infectious viral disease. true