passages.id: split_1_test_789_passage
passages.type: progene_text
passages.text: Prior to possible introduction of large - scale vaccination programmes , an estimation and comparison of naturally acquired immunity against Haemophilus influenzae type b ( Hib ) was carried out in two populations of age-stratified infants and children ( from birth to 14 years old ) in Burkina - Faso ( West Africa ) ( n = 206 ) and France ( n = 206 ) .