HIV-1 and HIV-2 infection in children in Abidjan, Côte d'Ivoire.

We conducted a study of 1,003 well and hospitalized children, birth to 5 years old, in Abidjan, Côte d'Ivoire, to determine the prevalence of HIV-1 and HIV-2 infection, evaluate risk factors for infection, and describe associated clinical characteristics. The overall seroprevalence was significantly higher for children in the hospital (10.8%) than for those attending the clinic (3.6%). HIV-1 was the predominant virus in both populations, comprising 87% (hospital) and 77% (clinic) of the seroreactive blood specimens. Ninety-two percent of seroreactive children of all ages had a mother who was HIV positive; 77% of seroreactive children greater than or equal to 15 months old had an HIV-infected mother. The remaining seropositive children had a history of receiving blood transfusions. Hospitalized children who were HIV-1 positive or dually seroreactive were more likely to have HIV-related clinical signs and symptoms than HIV-negative children. These findings suggest that HIV infection is an important cause of morbidity for children in Abidjan and that maternal infection is the primary risk factor for both HIV-1 and HIV-2 infection in children. Further evaluation and attention should be given to transmission, clinical characteristics, and the impact of HIV infection in children in West Africa, where both HIV-1 and HIV-2 are present.

Immunogenicity of a supplemental dose of oral versus inactivated poliovirus vaccine.

In many developing countries, the immunogenicity of three doses of live, attenuated, oral poliovirus vaccine (OPV) is lower than that in industrialised countries. We evaluated serum neutralising antibody responses in 368 children aged 6 months and 346 children aged 9 months in Côte d'Ivoire who had previously received three doses of OPV at 2, 3, and 4 months of age, and who were then randomised to receive a supplemental dose of OPV or enhanced-potency inactivated poliovirus vaccine (IPV) at the time of measles vaccination. Although both vaccines increased seroconversion to all three poliovirus types, antibody responses were greater in the IPV group. Among children with no detectable antibody at baseline, IPV was 2 to 14 times more likely than OPV to induce seroconversion (type 1, 80% vs 40% at 6 months [p < 0.001] and 81% vs 14% at 9 months [p < 0.001]; type 3, 76% vs 22% at 6 months [p < 0.001], and 67% vs 5% at 9 months [p < 0.001]. Among children with detectable antibody at baseline, IPV was 1.4 to 7 times more likely than OPV to elicit 4-fold or more rises in antibody titre (p < 0.01). Geometric mean titres (GMTs) to all three poliovirus types were also consistently higher among IPV recipients than in OPV recipients when measured 4-6 weeks and 13-17 months after vaccination. Administration of a supplemental dose of IPV or OPV, which requires no additional visits or changes in the existing immunisation schedule, might improve protection against paralytic poliomyelitis in communities with suboptimum seroconversion rates after three doses of OPV.