RESUMO
OBJECTIVES: To report the epidemiology of invasive Haemophilus influenzae type b (Hib) disease in high-risk Alaska Native infants before and after universal infant Hib vaccination and evaluate an increase in invasive Hib disease in 1996 after changing Hib vaccine type. STUDY DESIGN: Statewide laboratory surveillance for invasive Hib disease has been conducted since 1980. Three cross-sectional Hib carriage studies were conducted in 1997 and 1998. RESULTS: The invasive Hib disease rate in Alaska Natives decreased from 332 cases per 100,000 children <5 years old in 1980-1991 to 17:100,000 in 1992-1995 but increased primarily in rural areas to 57.9:100,000 after a switch in Hib vaccine types. Carriage studies in 5 rural Alaska Native villages showed oropharyngeal Hib carriage as high as 9.3% in children aged 1 to 5 years; in contrast, carriage in urban Alaska Native children was <1%. CONCLUSIONS: Although Hib disease has decreased in Alaska, the rate of Hib disease and carriage in rural Alaska Natives did not decrease to the same extent as in non-Natives and urban Alaska Natives. Use of polyribosylribitol phosphate-outer-membrane protein conjugate vaccine for the first vaccine dose is critical to disease control in this population with continued transmission in infants <6 months of age. The ability to eliminate Hib carriage and disease may be affected by population characteristics, vaccination coverage, and Hib vaccine type used. This may pose a challenge to global elimination of Hib.
Assuntos
Portador Sadio , Infecções por Haemophilus/prevenção & controle , Vacinas Anti-Haemophilus , Haemophilus influenzae tipo b , Orofaringe/virologia , Vacinas Conjugadas , Adolescente , Alaska/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Infecções por Haemophilus/epidemiologia , Infecções por Haemophilus/etnologia , Humanos , Lactente , Inuíte/estatística & dados numéricos , Vigilância da População , Fatores de Risco , Saúde da População Rural , VacinaçãoRESUMO
This study was undertaken to determine the extent to which anaemia in the mother is reflected in the neonate and to what extent iron and folate deficiency might contribute to maternal anaemia. Haemoglobin (Hb), serum iron, transferrin saturation, serum folate and red cell (RBC) folate were measured in blood samples taken from 85 mothers and from the umbilical cords at delivery. Forty-two per cent of the mothers were anaemic by WHO standards (Hb <110 g/l) and 27 per cent were anaemic using a cut-off point of 106 g/l. Twenty-eight per cent of the neonates were considered anaemic (cord Hb <136 g/l). Serum iron and folate and RBC folate were significantly higher (p<0.01) in cord than maternal blood. Only 3.5 per cent of the mothers had serum iron defiency(<8.1 æmol/l) while 35 per cent had serum folate deficiency (<6.8 æmol/l). At low (<106 g/l) compared to adequate (>110 g/l) maternal Hb, maternal mean serum iron and folate and RBC folate were all significantly lower (p<0.05). No significant differences were found in cord mean serum iron and folate and mean RBC folate between cord bloods with low Hb compared to those with adequate Hb. At deficient (<6.8 æmol/l) compared to adequate (>13.6 æmol/l) maternal serum folate, maternal mean Hb and mean RBC folate were significantly lower (p<0.001) and p<0.0001, respectively); similarly, both cord mean serum folate and mean RBC folate were significantly lower (p<0.0001 and p <0.001, respectively). These results suggest that mothers who are anaemic at parturition do not necessarily have anaemic babies except when the maternal anaemia is extremely severe. Folate deficiency appears to be a bigger contributor than iron deficiency to anaemia in pregnancy (AU)