Table 2.

Prevalence rates of neutralizing antibodies in a rural population from Minas Gerais State, Brazil

Interviewed	Prevalence rate (CI 95 %)
Overall	30.8 (25.3 - 36.9)
Vaccinateda (>35 years old)	53.1 (44.5 - 61.7)
Non-vaccinateda (≤35 years old)	6.1 (3.0 - 12.1)
Presence of vaccine takeb
Yes	57.1 (46.0 - 67.6)
No	18.4 (13.2 - 25.6)

^a: Vaccinated and non-vaccinated individuals were determined according to their age, which correspond that >35 years old participated of smallpox eradication campaign

^b: The presence of vaccine take were determined by examination on left arm of each individual