Vaccine Facts: Boost Your Immunization Knowledge
Author:博沃管理员 Release time:2018-07-24 16:24:09
Only Clean Water Outperforms Vaccination
If you wanted to pick the most significant event in human history that reduced the spread of infectious diseases, improved sanitation including clean water and proper sewerage disposal would be number one.
But vaccination runs a close second, sitting ahead of antibiotics. Vaccination has had a major effect on reducing death rates and enhancing population growth. Dr Edward Jenner has long been lauded as the founding father of vaccination - when he formally demonstrated how a previous inoculation with cowpox protected a 8-year-old boy from a subsequent inoculation with smallpox.
Following a world-wide vaccination campaign that started in 1967, smallpox has not been seen since 1977, and the World Health Organization (WHO) has officially declared the disease eradicated worldwide, saving an estimated five million lives.
The Benefits Of Vaccination Are Real
Smallpox isn't the only disease that has been impacted through vaccination. Other vaccine-preventable diseases - such as polio, diptheria, tetanus, yellow fever, measles, and pertussis (whooping cough) - have all seen significant declines in their prevalence directly attributable to immunization.
There is a high chance that polio could be the next disease to be eliminated world-wide. Thanks to a global effort to eradicate the disease, only three countries - Pakistan, Nigeria, and Afghanistan - remain polio-endemic. Case numbers have decreased by over 99%, from an estimated 350,000 in 1988 to 22 reported in 2017.
But eliminated does not mean eradicated. Outbreaks of supposedly eliminated diseases, such as measles, regularly occur, particularly among unvaccinated communities.
No Vaccine is 100% Effective
No vaccine is 100% effective, which means that a few vaccinated children will still succumb to a disease if there is an outbreak; usually in a much milder form.
For example, measles has 97% efficacy after 2 doses (meaning 3 out of 100 vaccinated children will still get measles if exposed to it). Compare this to no vaccination, and an almost 100% chance of catching the disease. Measles is so contagious that you could catch it just by walking into a room that an infected person has left hours before. Some other vaccines, notably pertussis (whooping cough) have lower efficacy rates (86% after 3 doses).
One of the biggest outbreaks of measles occurred during 2014-2015, when 667 cases were reported. Although the original source was not identified, it was most probably somebody who had been overseas recently - the Philippines were in the midst of an outbreak at the same time. Measles remains common in Europe, Asia, the Pacific, and Africa.
