Waec Model Questions Vol1 2022 Biology Question 15

Practice objective / multiple choice question 15 from the 2022 Waec Model Questions Vol1 Biology examination.

Waec Model Questions Vol1 2022 Biology Objective / Multiple Choice Hard Difficulty
Question 15 WAEC_MODEL_QUESTIONS_VOL1 • 2022 • BIOLOGY • objective

In a closed community of 10 000 people an infectious disease has a basic reproduction number $R_{0}=2.5$. A vaccination programme immunises 60 % of the population with a vaccine that is 90 % effective. Assuming homogeneous mixing, (i) calculate the effective reproduction number $R_{e}$ after vaccination and state whether herd immunity is achieved, and (ii) determine the minimum vaccination coverage (with the same vaccine efficacy) required to achieve herd immunity.

Answer Options

A. Re = 1.30 (no herd immunity); minimum coverage ≈ 55 %
B. Re = 0.75 (herd immunity); minimum coverage ≈ 80 %
C. Re = 0.90 (herd immunity); minimum coverage ≈ 60 %
Correct Answer D. Re = 1.15 (no herd immunity); minimum coverage ≈ 66.7 %
Correct Answer
D
Correct Option:
Re = 1.15 (no herd immunity); minimum coverage ≈ 66.7 %

About This Question

This is Waec Model Questions Vol1 2022 Biology Question 15. It is a objective / multiple choice question from the 2022 Waec Model Questions Vol1 Biology examination.

Difficulty level: Hard .

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