HOW VACCINES WORK: question 34 (What is the main advantage of vaccines compared to natural infection?)

B: They train the immune system without causing serious illness.

HOW VACCINES WORK: question 35 (Why are booster shots sometimes necessary?)

B: Because the immune memory can weaken after a while

Reading answers with explanations

Multilevel · Part 5 · Real Exam Multilevel Test 1 (2026)

HOW VACCINES WORK: Reading answers

Answers to questions 30–35 (6 in all), each with why it is right.

Sit it first, then check

Read the whole passage and answer in the exam interface, timed as on the day.

Practise this part

The passage opens

For more than two hundred years, vaccines have been one of the most powerful tools in modern medicine. They have helped people live longer, healthier lives by preventing diseases that once killed millions. To understand how vaccines work, it is useful to first look at how the human immune system protects the body, what happens when a vaccine is given, and why vaccines are so important for both individuals and communities. The human body has a defense system called the immune system. Its main job is to protect us from harmful invaders, such as viruses and bacteria. When these invaders, also known as pathogens, enter the body, the immune system recognizes them as dangerous and starts…

Answers 30–35

30
immune Note completion
The passage calls the body's defense system the “immune system,” matching the note’s system used to fight viruses and bacteria.
“The human body has a defense system called the immune system.”
31
memory Note completion
The passage says the immune system remembers a pathogen after fighting it. This matches keeping a memory of the germ for the future.
“After fighting an infection once, the immune system “remembers” the invader.”
32
safe Note completion
The passage says vaccines show the body a “safe version” of the pathogen, matching the form used to prepare the immune system.
“It works by showing the body a safe version of a pathogen.”
33
herd Note completion
The passage names this community protection “herd immunity.” The note uses the same term for protection when enough people are vaccinated.
“When enough people are vaccinated, the disease has little chance to spread. This protects those who cannot receive vaccines, such as newborn babies or people with certain medical conditions.”
34
What is the main advantage of vaccines compared to natural infection?
B: They train the immune system without causing serious illness. Multiple choice
The passage says vaccines train the immune system without causing the disease, matching option B’s idea that they do so without causing serious illness.
“A vaccine is a medical product that trains the immune system without causing the actual disease.”
35
Why are booster shots sometimes necessary?
B: Because the immune memory can weaken after a while Multiple choice
The passage explains that booster shots may be needed because immune memory can fade over time. This matches option B, that immune memory can weaken after a while.
“The reason is that immune memory can fade over time.”

HOW VACCINES WORK: Reading answers

The passage opens

Answers 30–35

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