News: Samoa measles toll hits 42 as nations dispatch medical teams, supplies, page-5

The article says the coverage rate is 31% and science tells us the measles vaccine is 97% effective.

200,000 people - 62,000 vaccinated and 138,000 unvaccinated.

Let ”I” be the infection rate for the unvaccinated population

3,149 = 138,000 I + 62,000 x (1-0.97) x I

so

3,149 = (138,000 + 1,860) x I

so I = 2.25%

So for those who were vaccinated 2.25% x (1-.97) x 62,000 would contract measles which is 41 of the 3,149 who contracted measles

Obviously a statistical estimate but likely to very close.