Assessment 3

Question 5

The country of Rubovia has a population of 60 million and the annual incidence of Guillain Barre syndrome is 2/100,000 individuals.

In an immunisation campaign, 5 million adults were immunised with an influenza-A vaccine. In the 8 weeks following immunisation 26 of them developed Guillain Barre syndrome.

Calculate the vaccine-attributable rate of Guillain Barre syndrome per 100,000 immunised individuals.

Select one:

	A. 0.2
	B. 26
	C. 10
	D. 16
	E. 1

Answer

Answer A is correct.

The expected incidence of Gullain Barre syndrome in a population of 5million people in an 8 week period is:

5,000,000 x 2/100,000 x 8/50 =16

The number observed is 26, therefore the excess is 26 – 16 = 10

The excess incidence is 10/5,000,000 = 0.2/100,000 vaccinated individuals.

The correct answer is: 0.2.

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