Analyzing the Passage and Finding the Right Word for Blank 5

The question asks us to find the most appropriate word to fill in blank number 5 in the given passage about an experimental coronavirus vaccine trial. Let's look at the sentence containing blank 5:

"Such early trials are usually designed only to (4) ______ safety, but in this case, experts were also looking to see what kind of immune response was (5) ______ ."

The sentence describes what the experts were observing during the trial. The trial involved giving an experimental vaccine. Vaccines are designed to stimulate, or cause, an immune response in the body, preparing it to fight off a disease. The phrase "what kind of immune response was ______" means the experts were looking to see what immune response was *caused* or *produced* by the vaccine.

Evaluating the Options for Blank 5

Let's examine each option to see which word best fits the context of an immune response being caused by a vaccine:

• reduced: This means made smaller or less. A vaccine aims to *increase* the body's preparedness, which involves strengthening or prompting an immune response, not reducing it. So, 'reduced' is incorrect.
• provoked: This means stimulated, aroused, or called forth. In the context of biology and medicine, 'provoking' an immune response is a common way to describe a substance (like a vaccine) causing the body to react defensively. This word fits perfectly with the idea that the experts were looking to see the immune response that the vaccine caused. The passage itself uses "prompt a protective immune response" earlier, and "provoked" is a suitable synonym for "prompted" in this context.
• sheltered: This means protected or shielded. An immune response is something that *provides* shelter or protection to the body, but the response itself is not typically described as being 'sheltered'. So, 'sheltered' does not fit the context.
• lessened: This also means reduced or decreased. Similar to 'reduced', this is the opposite of what a vaccine is intended to do to the immune response. So, 'lessened' is incorrect.

Conclusion for Blank 5

Based on the analysis, the word that means 'caused' or 'stimulated' an immune response is 'provoked'. The experts were looking to see what kind of immune response was stimulated or brought about by the vaccine.

Therefore, the most appropriate option to fill in blank number 5 is "provoked".

Revision Table: Understanding Vocabulary in Context

The word "provoked" is the only option that accurately describes how a vaccine causes or stimulates an immune reaction in the body.

Additional Information: Vaccine Trials and Immune Response

Vaccine trials typically go through several phases:

• Phase 1: Small group of people. Focuses on safety and dosage. Experts look for any side effects and check if the vaccine causes an immune response.
• Phase 2: Larger group of people. Continues to assess safety and dosage, but also starts to look more closely at how well the vaccine works (immunogenicity) and the immune response it provokes.
• Phase 3: Large group of people (thousands). Tests the vaccine's effectiveness in preventing the disease and monitors for rare side effects.

An immune response is the body's way of recognizing and defending itself against foreign substances like viruses or bacteria. A vaccine contains a harmless part of a pathogen (or instructions to make a harmless part) that prompts the immune system to build defenses (like antibodies) without causing the disease. In early trials like the one described, checking if an immune response is successfully provoked is a key step in determining if the vaccine has the potential to work.