passages.id: split_1_test_791_passage
passages.type: progene_text
passages.text: The difference in the percentages of minimum protective levels for the two populations were not significant ( 0.15 microg / ml ) for newborns ( 0 - 1 month ) but became significant as early as 2 to 3 months of age ( p < 0.01 ) when lower levels were found among infants from Burkina - Faso .