At school you read about science, history and geography in English, and you answer exam questions about them. Read this short article, then answer 2 exam-style questions and write one answer yourself. Everything you need is in the article.
Tap a bold word to see what it means.
When you were a baby, a nurse probably gave you several injections. Each one was a vaccine, and each one taught your body to fight a disease before you ever met it. How can an injection teach the body anything?
Diseases such as measles are caused by : tiny living things, such as viruses, that get inside the body and multiply. Every pathogen carries molecules on its surface called . Antigens work like a name badge. Each kind has a particular shape, and different pathogens have antigens with different shapes.
Your body defends itself with white blood cells. Some of these cells make . An antibody has a shape that fits one kind of antigen exactly, in the same way that a key fits a lock. Antibodies stick to the pathogens and mark them, so that other white blood cells can destroy them. The problem is time. The first time a new pathogen enters the body, it takes a week or more to make enough of the right antibodies. During that week the pathogen keeps multiplying, and you become ill.
A vaccine solves this problem in advance. It contains a weakened or dead form of the pathogen, or only its antigens, so it cannot make you ill. However, it still your white blood cells to make the matching antibodies. Some of these cells also become memory cells, which stay in your blood for many years.
If the real pathogen arrives later, the memory cells recognise its antigens at once. They make the right antibodies much faster than the first time, and in much larger numbers. The pathogen is destroyed before it can multiply, so you do not become ill. You are now to that disease.
Vaccines also protect people who cannot have them, such as newborn babies or people who are already very sick. When most people in a community are immune, a pathogen cannot easily spread from person to person, so it rarely reaches the few who are not protected. This is called herd . It is the reason doctors talk about vaccines not only as a choice for one person, but as a way to protect a whole community.
Which answer does what the question asks?
Now write your own answer · 3 marks
A newborn baby is too young to have the measles vaccine. Explain how vaccinating most people in the baby's community can still protect the baby.
More articles at B2 are coming soon.
Keep going
Create a free account to practise the words you met here and read the next article.
Create a free accountArticle written for Axiom. Word levels: CEFR-J Wordlist v1.6 (Yukio Tono, TUFS) · Octanove Vocabulary Profile C1/C2 (CC BY-SA 4.0).