Question

Which people are at risk of getting a particular disease?
A. Who never had a vaccine
B. Who didn’t receive all doses of vaccine
C. Who travel to disease prevalent areas
D. All of the above

Answer 1

Hint:Immunity is the ability of an organism to recognize the foreign material (organisms or chemicals) that enter the body and to mobilize the cells and cell products to speedily remove that foreign material. The study of the body's natural defense mechanism against pathogens and toxic material is known as immunology. The vulnerability of a person to infectious agents is called susceptibility. It is the opposite of immunity.

Complete answer:A person may develop immunity in three different ways
1. Immunity through diseases: response of a person to the infection of a pathogenic organism varies through time. The first time he gets an infection of a pathogen. Subsequent infection of the same microorganisms does not cause the disease. In the case of the first infection, antibody formation is slow and the virus has time to multiply and spread throughout the body. Thus disease appears. Eventually, antibody formation picks up and disease disappears.
2. Vaccination: it is a technique to develop immunity without infection. Weakened or dead pathogens, or portions of pathogens, are injected into a person who is required to be made immune. The pathogens given in the vaccine are unable to cause the disease but are sufficient to stimulate the formation of antibodies by the host’s immune system that recognizes the antigens. Thus, a vaccinated person develops immunity against the pathogen without contracting the disease.
3. Antitoxins: Antibodies that neutralize toxins produced in the body or introduced from outside.
People who are at risk of disease are those who never had vaccines, who didn’t receive all doses of vaccines, and who travel to places prevalent to disease.

So the correct answer is option is D. All of the above.

Note:There are two major types of immunity: innate or inborn and acquired or adaptive. The type of immunity inherited by an organism from the parents and protects it from birth throughout life is known as inborn immunity. The immunity developed by an animal in response to disease caused by infection of microbes.