Igcse Model Questions Vol1 2017 Biology Question 36

Practice objective / multiple choice question 36 from the 2017 Igcse Model Questions Vol1 Biology examination.

Igcse Model Questions Vol1 2017 Biology Objective / Multiple Choice Hard Difficulty
Question 36 IGCSE_MODEL_QUESTIONS_VOL1 • 2017 • BIOLOGY • objective

In a closed community of 5 000 people, an infectious disease initially infects 10 individuals. After 3 days the number of infected individuals rises to 80. Assuming exponential growth, the generation time (average interval between successive infections) is 2 days. (a) Calculate the basic reproduction number \(R_0\) for the disease. (b) A vaccine with 90 % efficacy is introduced. What is the minimum proportion of the total population that must be vaccinated to reduce the effective reproduction number below 1?

Answer Options

Correct Answer A. R₀ = 4; minimum vaccination proportion ≈ 0.84 (84 %)
B. R₀ = 6; minimum vaccination proportion ≈ 0.65 (65 %)
C. R₀ = 3; minimum vaccination proportion ≈ 0.75 (75 %)
D. R₀ = 5; minimum vaccination proportion ≈ 0.90 (90 %)
Correct Answer
A
Correct Option:
R₀ = 4; minimum vaccination proportion ≈ 0.84 (84 %)

About This Question

This is Igcse Model Questions Vol1 2017 Biology Question 36. It is one of the objective questions from the 2017 Igcse Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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