[Seroprevalence of human immunodeficiency virus infection among pregnant women in Brazzaville]

A serological study aimed at measuring the distribution and extent of the HIV infection in the population was carried out from 1 October to 30 November 1990 among 689 pregnant women seen during prenatal consultations in the Health Centers of the National Social Security Service. Serological tests according to ELISA method were used. They were anonymous and uncorrelated. Specific seroprevalence was found to be high among young women between 20 and 29 years (10.10%) and among nulliparous women. Some correlation was observed between the parity and the seropositivity; the seroprevalence was higher among nulliparous women (chi 2 = 52.4; ddl = 4; p < 0.001). The authors recommend the reinforcement of preventive measures and the establishment of counselling in Mother and Child Health Care Centers (MCH).

[Study of weaning foods in infants in Brazzaville]

The authors have searched the characteristics of weaning for 400 children from 0 to 24 months examined in mother and child health centre of Brazzaville. The study has revealed that the exclusive feeding to the breast is the predominant method (81.5%). The weaning paps utilized are in great part local (64.3%) but their preparation and their method of keeping them constitute a real problem. The sudden weaning has been observed in 87.2% of the cases. The recommended feeding square wasn't yet regarded so that the protidic foods were little consumed (44.0%) as well as protective foods too (50.4%).

Loss of maternal measles antibody during infancy in an African city

Measles epidemics with 20% of the cases under nine months of age continue to occur in Brazzaville, Congo, even though measles vaccination coverage was 77% in the 12- to 23-month age group in 1986. In order to estimate the duration of passive immunity against measles, we conducted a serologic survey of infants aged 2 to 9 months. Measles antibody was measured from capillary blood with the plaque inhibition test. An antibody titre of 40 milli-International Reference Units per ml of serum (mIRU/ml) or less was defined as seronegative. Among the 252 infants studied, the proportion with detectable antibody dropped from 95.8% at 2 months of age to 48.5% at 4 months of age, and to 8.2% in the 7-8 month age group. A simple logistic model with age as the only variable provided an excellent fit to the observed values. Between the ages of 8 and 28 weeks, there was an almost steady decline of approximately 4.7% per week in the proportion of infants who were seropositive. These findings suggest that loss of maternal measles antibody during infancy might be faster than reported in other African populations. Giving measles vaccine to infants before the age of nine months currently recommended by the Expanded Programme on Immunization may be useful in some populations. Further studies of seroconversion and impact on measles are needed.

The epidemiology of measles in a partially vaccinated population in an African city: implications for immunization programs

A large outbreak of measles was reported in Pointe-Noire, Congo, between October 1984 and March 1985. An investigation was conducted to determine the epidemiology of measles in this community in which, in 1985, 54% of the children 12-23 months of age had documented evidence of vaccination against measles. The investigation included hospital and clinic record reviews and a community survey. Measles has been continuously transmitted in Pointe-Noire since at least 1979, with seasonal epidemics. In early 1984, the expected epidemic did not occur, and at least 1,000 measles hospital admissions and 100 measles deaths were prevented. Between October 1984 and March 1985, 1,942 measles cases were hospitalized, of which 306 (15.8%) died. During the epidemic, the proportion of nonpreventable cases (cases occurring before nine months of age) was 17%, reflecting the change in age distribution of measles cases in childhood since the immunization program started in Pointe-Noire in 1982. From the community survey, it was estimated that 13% of all children under age five years acquired measles in Pointe-Noire in 1985. Vaccine efficacy was calculated from community and hospital samples to be between 78% and 87%. Our findings suggest that increasing vaccination coverage levels to well above 50% is necessary to substantially reduce measles morbidity and mortality in African cities.