Quiz week 17

The incidence of malaria in a south east Asian country with a population of 500,000 is 2500 cases every month.

A young scientist has come up with a new prevention.

Out of the 30000 subjects who received the new intervention over the last month, there have been 30 cases.

Q1. How many people need to receive the intervention to prevent one case?

  1. 200
  2. 250
  3. 180
  4. 1000
  5. More information is required to say this

The answer is Choice 2. The incidence per 1000 population ia 5 (2500/500K). After the intervention, the incidence drops to 1/1000 (30/30K) among those prophylaxed.

The drop is 4/1000 prophylaxed.
For preventing 1 case, the number needed to treat is 1000/4 = 250.

Q2. The cost of each course of new prevention is $8. What is the cost of preventing 1 case?

  1. $1600
  2. $2000
  3. $8000
  4. $1800
  5. Cannot calculate using the data given.

The answer is choice 2. The cost of one prophylactic intervention is $8. Therefore to prevent one case, the cost is $8 x 250 = $2000.