NATURAL IMMUNITY TO HAEMOPHILUS-INFLUENZA E INFECTION TYPE-B OF INFANT IN BURKINA-FASO

Background.- Natural immunity to Haemophilus infection type b that is acquired by the mothers and passively transmitted to their newborns is not well-known in developing countries, where the frequency of Haemop hilus meningitis in infancy is high. Population and methods. - Blood s amples (5 ml) were taken from 89 women at the time of delivery and fro m the cord of their babies. Blood samples were also taken from 290 inf ants and children, distributed into nine subgroups as a function of th eir age. Children with protein-calorie malnutrition and immune deficie ncy were excluded from the study. Antibodies against Haemophilus influ enzae were measured by Elisa and radioimmunologic methods. Blood conce ntrations of 0.15 pg/ml or more were considered to be protective. Resu lts. - All the blood samples of mothers and cords contained protective levels of antibodies, as did the samples from 30% of those infants ag ed 0-60 days (all the infants were less than I month). No infant in th e subgroup 12-23 months had protective levels of antibodies. The incid ence of Haemophilus meningitis runs correlated with the absence of ant ibodies. Conclusion. - Maternal immunity is gradually lost by babies d uring their first 2 months of life, earlier than in developed countrie s. Early vaccination, at 3 months of age, is mandatory.