Commonly used vaccines for influenza are trivalent and contain only one type of

ID: 3298985 • Letter: C

Question

Commonly used vaccines for influenza are trivalent and contain

only one type of influenza B virus. They may be ineffective

against other types of influenza B virus. A randomized

clinical trial was performed among children 3 to 8 years of

age in 8 countries. Children received either a quadrivalent

vaccine (QIV) that had more than one influenza B virus or a

trivalent Hepatitis A vaccine (control) (Jain, et al., [9]. New

England Journal of Medicine 2013: 369(26): 2481–2491).

An attack rate (i.e.,% of children who developed influenza)

starting 14 days after vaccination until the end of the study

was computed for each vaccine group, stratified by age.

The following data were reported:

3.28 Suppose 3 children in a village ages 3, 5, and 7 are

vaccinated with the QIV vaccine. What is the probability

that at least one child among the 3 will get influenza?

TABLE 3.7 Attack rate for influenza by age and treatment group OlV group Control group age 3-4 5-8 5.69% 5.15% 3.7896

3.28)

the probability that age 3-4 will get influenza who are vacinate with QIV = 0.0378

the probability that age 3-4 will not get influenza who are vacinate with QIV =1- 0.0378

the probability that age 5-8 will get influenza who are vacinate with QIV = 0.017

the probability that age 5-8 will not get influenza who are vacinate with QIV =1- 0.017

the probability that at least one child among the 3 will get influenza

= 1 - none of them get influenza

= 1 - (1 -0.0378)*(1-0.17)^2

= 0.33714042

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