Herd immunity is defined as which of the following?

Herd immunity is defined as which of the following?

• A. Immunity in Most of a Population
• B. Immunity in a Few Individuals
• C. Immunity Only After Vaccination
• D. Immunity Achieved Through Treatment

Answer: (A)

Herd immunity occurs when a large portion of a population becomes immune to a disease, so the pathogen has fewer opportunities to spread. When enough people are immune, transmission chains are broken, providing protection to those who aren’t immune, such as individuals who cannot be vaccinated or who didn’t develop immunity. The exact amount of immunity needed depends on how contagious the disease is; more contagious diseases require a higher proportion immune to stop spread. Immunity in only a few individuals wouldn’t prevent transmission, and immunity isn’t limited to vaccination—people can also gain immunity from past infection, though vaccination is the safer, more reliable path. Immunity obtained through treatment does not confer lasting protection.

Herd immunity occurs when a large portion of a population becomes immune to a disease, so the pathogen has fewer opportunities to spread. When enough people are immune, transmission chains are broken, providing protection to those who aren’t immune, such as individuals who cannot be vaccinated or who didn’t develop immunity. The exact amount of immunity needed depends on how contagious the disease is; more contagious diseases require a higher proportion immune to stop spread. Immunity in only a few individuals wouldn’t prevent transmission, and immunity isn’t limited to vaccination—people can also gain immunity from past infection, though vaccination is the safer, more reliable path. Immunity obtained through treatment does not confer lasting protection.