CIE A Level Biology复习笔记11.2.6 Vaccination to Control Disease
Vaccination to Control Disease
- With the exception of the great success story surrounding the eradication of Smallpox following a ten year global initiative in 1980 no other pathogen has been eradicated globally since
- Smallpox was able to be eradicated because a ‘live attenuated’ vaccine was used against the only strain of the virus. There was also a programme of surveillance, contact tracing and ‘ring’ vaccinations
- There are many safe and effective vaccines that do exist against many pathogens and these have managed to push a number of childhood diseases to the verge of extinction
- Vaccines against such diseases as mumps, chicken pox and whooping cough are administered to children as part of an immunisation schedule and they successfully confer immunity
- As a result many childhood diseases are kept at low levels within populations due to herd immunity
- Herd immunity arises when a sufficiently large proportion of the population has been vaccinated (and are therefore immune) which makes it difficult for a pathogen to spread within that population, as those not immunised are protected and unlikely to contract it as the levels of the disease are so low
- Although most vaccinations are given to children there are some vaccines that are provided at later stages in life, for example vaccinations for tuberculosis (TB) and Hepatitis B are offered to frontline medical workers who have a higher risk of coming into contact with such diseases in the hospital setting;Travellers may be advised to take particular vaccines if travelling to areas where certain diseases are endemic such as Yellow Fever in parts of Africa
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