Question

Of the following answers, which correctly describes why herd immunity against SARS-CoV-2 would result in reduced transmission of the virus?

a.) the virus can infect individuals with immunity, but the immune system would ignore the virus, so no symptoms would occur

b.) the virus is unable to enter and infect individuals who have immunity

c.) individuals with immunity would have a rapid and effective humoral immune response against the virus which would prevent the virus from replicating and shedding

d.) individuals with immunity would have a stronger innate immune response against SARS-CoV-2 so macrophages would recognize and destroy the virus quicker

Answer 1

Correct Answer: Option C

Explanation:

• When most of the people in a community become immune to an infectious disease, they provide indirect protection to the rest of the community. This is called herd immunity.
• A contagious disease spreads from person to person.
• The pathogen infects the host and spreads from that index host to other people.
• This helps the disease to propagate in the community.
• Now, if a 70 - 80 % of the population is vaccinated against the disease, then they develop good humoral immunity against the disease.
• So when they are infected with pathogens, their bodies will develop an immune response and curtails the infection.
• As a result, the infection doesn't progress to disease or if it does progress to disease, the disease is milder and short-lived.
• They prevent person to person transmission of the pathogen.

Incorrect answer:

Option a - incorrect - the immune system of a healthy individual will never neglect any pathogenic invasion.

Option b - incorrect - The virus can infect. But if the patient has developed immunity due to previous infection or vaccination, this infection cannot develop into disease.

Option d - incorrect - the innate immunity doesn't protect against SARS-COV-2.