Question

Complete the hypothesis below to answer the lab question, “What is the effect of immunity on the rate at which a disease spreads?”

Hypothesis: If a higher percentage of people are immune to a disease, then . . .

because . . .

Answer 1

Hypothesis: If a higher percentage of people are immune to a disease, then the disease will spread more slowly (fewer new infections per unit time) and outbreaks will be smaller or may stop entirely when immunity is high enough,

because with more immune people there are fewer susceptible hosts for an infected person to infect, which lowers the effective reproduction number (R_e = R0 × (1 − proportion immune)) and can reduce R_e below 1, preventing sustained transmission.