Inoculation was practiced in China in the 17th century where the Chinese used smallpox material to provide immunity to that disease. This technique was also practiced in Africa and Turkey and had spread to Europe and America later on.
Edward Jenner is known as the founder of vaccinology in 1796 after he inoculated a boy with cowpox which gave him the ability to be immune against smallpox. In 1798, the first smallpox vaccine was developed and it was used globally, resulting in the eradication of smallpox in 1979.
The production of vaccines is strictly regulated, and has undergone different stages of testing before it can be introduced to us. There are various types of vaccines, such as:
- Inactivated vaccines: killed version of the germ that causes the disease is used
- Live-attenuated vaccines: weakened form of the germ that causes the disease is used
- Subunit, recombinant, polysaccharide, and conjugate vaccines: specific pieces of the germ is used (eg. its protein or aspid)
- Viral vector vaccines: a modified version of a different virus is used as a vector to deliver protection
- Toxoid vaccines: toxins produced by the germ that causes the disease is used
Vaccines not only protect you from diseases, but also your family, friends and other people within your community. It has prevented up to 3 million deaths worldwide each year.
COVID-19 section:
How to compare the Pfizer, Oxford and Moderna vaccines?
1. Methods
① traditional inoculation - The Oxford vaccine
A spike protein is injected to the body and triggers a response of immune system.
② mRNA technology - Pfizer and Moderna
A messenger sequence that contains genetic information is introduced to let the cells in the vaccinated person make antigens.
2. Effectiveness
Final data from the Pfizer vaccine found it offers 95% protection against the virus after two doses.
It also proved 94% effective among adults over the age of 65 - who are generally more vulnerable.
Moderna's results indicate 94.5% effectiveness but it said the trials are ongoing and the final number could change.
The Oxford trial found with two doses its vaccine was 62% effective. Agencies also concluded that the Oxford vaccine was up to 80% effective when the second dose was delayed by three months.
3. Transport and storage
Most vaccines have to be stored at low temperatures (about -70 ~ -20℃) and protected from light.
4. Costs
5. Availability
The UK government has secured around 40 million doses of the Pfizer vaccine - enough for 20 million people or about a third of the UK population.
The UK has ordered five million doses of the Moderna vaccine, to be delivered by spring. Health Secretary Matt Hancock said this candidate would not be available anywhere in Europe until then.
The government has reserved 100 million doses of the Oxford vaccine, which it has helped fund.
Must-read webpage:
https://www.nhs.uk/conditions/vaccinations/why-vaccination-is-safe-and-important/
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