Efficacy of BCG vaccination of the newborn: evaluation by a follow-up study of contacts in Bangui.

BACKGROUND: The efficacy of Bacillus of Calmette and Guérin (BCG) vaccination given at birth is still controversial. We therefore conducted a study in Bangui (Central African Republic) to estimate the protection afforded over the first seven years of life by BCG administered at birth. METHODS: One thousand children who had lived in contact with a recently diagnosed case of contagious tuberculosis were followed up for a period of 6 months in order to detect the occurrence of tuberculosis. Diagnosis of tuberculosis was made through a scoring system. Vaccine efficacy (VE) was calculated on the basis of the relative risk of contracting tuberculosis according to vaccination status. RESULTS: The efficacy of BCG was estimated to be 71% (95% confidence interval: 56-81%). This result remained practically the same after changing the definition used for tuberculosis cases (VE = 75% for a threshold with a score of 15 instead of 6, VE = 74% when only confirmed cases were considered). There was no difference between the two groups in the variables measuring intensity of contact with the source of contamination, but there was a difference in age distribution. Vaccine efficacy adjusted for this factor was the same as the crude VE. CONCLUSION: This study, based on a methodology that controls for most of the risks of bias inherent to field efficacy measurement, confirms the protective capacity of neonatal BCG against childhood tuberculosis. Therefore BCG vaccination at birth must remain a public health priority especially in countries with high incidence of the disease.

PIP: The efficacy of Bacillus of Calmette and Guerin (BCG) vaccination given at birth is still controversial, therefore a study was conducted in Bangui, Central African Republic, to estimate the protection afforded over the first 7 years of life by BCG administered at birth. 1000 children who had lived in contact with a recently diagnosed case of contagious tuberculosis (TB) were followed up from May 1989 to February 1991 in order to detect the occurrence of TB. 896 of them were considered as vaccinated. Diagnosis of TB was made through a scoring system endorsed by the World Health Organization. Contact children with a score of or= 6 were considered to have TB. Four groups of children were formed in order to calculate the risk of TB in relation to vaccination status: children with TB who had been vaccinated, children with TB who had not been vaccinated, healthy children who had been vaccinated, and healthy children who had not been vaccinated. Vaccine efficacy (VE) was calculated on the basis of the relative risk of contracting TB according to vaccination status. Of the 1000 contact children, 91 had a score of or= 6. The TB incidence rate was 7.3% in vaccinated children and 25% in nonvaccinated children, which corresponded to a 0.29 relative risk of contracting TB or efficacy of BCG of 71% (95%, confidence interval: 56-81%). This result remained practically the same after changing the definition used for TB cases (VE = 75% for a threshold with a score of 15 instead of 6, VE = 74% when only confirmed cases were considered). There was no difference between the 2 groups in the variables measuring intensity of contact with the source of contamination, but there was a difference in age distribution. BCG vaccination at birth must remain a public health priority, especially in countries with high incidence of the disease in view of the protective capacity of neonatal BCG against childhood TB.

[Tuberculous allergy in a population of 3-to-23-month-old children in Bangui (Central African Republic)]. / Etude de l'allergie tuberculinique dans une population d'enfants âgés de 3 à 23 mois à Bangui (Republique Centrafricaine).

In 1986, vaccinal allergy has been looked for by tuberculin RT 23 intradermal reaction within a random group of 354 Central African Children aged of 3 to 23 months and immunized in the Mother and Child Care Services in Bangui in the framework of the Enlarged Vaccination Program, with the same B.C.G. strain during their postnatal period. Percentage of intradermal reactions equivalent or superior to 6 mm get down with time, of progressive but fast mode from 56.2 p.c. in the age group of 3 to 5 months to 20.2 p.c. in the ones of 12 to 23 months. Nevertheless, the authors recommend B.C.G. immunization in urban milieu during the postnatal period because of the strong vaccinal protection one get, but recommend also a systematic booster injection during the second year of childhood.

Detection of anti-HIV IgA in tears of children born to seropositive mothers is highly specific.

In order to improve the diagnosis of HIV infection in children born to seropositive mothers, 86 children were previously tested by Western blotting for anti-HIV IgA in tears and IgG in serum, at a median age of 9.2 months. To determine the exact value of the assay, 68/86 children of the same cohort were retested 9 months later. Nine children (13.4%) were seropositive and all had anti-HIV IgA in tears. Eight of them had possessed lachrymal antibodies 9 months earlier. The ninth child was seronegative when 9 months old and then seroconverted. Four children (6%), known to be seronegative, had an indeterminate Western blot pattern and no HIV IgA in tears. Fifty four (80.6%) were seronegative at 18 months; none of them had ever had anti-HIV IgA in tears. This highlights the fact that only the children without lachrymal HIV IgA at the age of 9 months became seronegative at the age of 18 months. Our results clearly show that the detection of anti-HIV IgA in tears is a highly specific and reliable diagnostic test in children aged less than 15 months, born to seropositive mothers.

HIV-specific IgA antibodies in tears of children with AIDS or at risk of AIDS.

To improve on the diagnosis of human immunodeficiency virus (HIV) infection, 14 children with clinical evidence of AIDS, 86 children less than 15 months old and born to seropositive mothers, and 29 controls were tested for the presence of IgA antibody in tears directed against HIV antigens on Western blots. IgA antibodies in tears against env- and pol-encoded proteins were present in 13 of 14 children with AIDS and in 13 of 86 children born to seropositive mothers. No HIV-specific IgA was observed in tears of the 29 controls. Among the 86 children less than 15 months old, 11 had clinical evidence of AIDS and 7 of them (64%) had HIV-specific IgA in tears. Results show that the demonstration of lacrimal HIV-specific IgA may help to distinguish between truly infected children and those whose HIV antibodies are passively transferred from the mother. Therefore, this simple method is a good tool for laboratory diagnosis of paediatric AIDS.

[Morbidity and mortality in the pediatric service of Banqui (Central African Republic) during the year 1990. Implications for public health]. / Morbidité et mortalité dans le service de pédiatrie de Bangui (Centrafrique) au cours de l'année 1990. Implications en matière de santé publique.

Hospitalizations in the department of pediatrics of the Bangui Hospital (Central Africa) during the year 1990 were evaluated in terms of mortality and morbidity. During the study year, 8,052 children were admitted. Overall in-hospital mortality rate was 11.6%. Most deaths occurred shortly after admission (60% within 24 hours), in patients less than one year of age. Analysis of morbid conditions highlighted the growing severity of malaria and anemia in the youngest patients. Since no other facilities for inpatient treatment of children exist in the area, the data presented here can be considered as reflecting local medical problems and, therefore, can be used to guide public health decisions.

Characteristics of serogroup A Neisseria meningitidis strains isolated in the Central African Republic in February 1992.

A severe epidemic of serogroup A meningococcus meningitis occurred in the northwest Central African Republic from January to March 1992. Strains from 24 patients were characterized using serotyping, testing of susceptibility to antibiotics, and multilocus enzyme electrophoresis. In 23 of the 24 patients the causal strain was found to be 4:P1.9/clone III-1. These results indicate that such strains continue to spread in Africa and have taken hold in areas outside the "meningitis belt." This may be a consequence of changing climatic conditions.

Evaluation of the efficacy of a low-passage bovine rotavirus (strain WC3) vaccine in children in Central Africa.

The safety and efficacy of a WC3 rotavirus vaccine was evaluated in a double-blind placebo-controlled trial involving 472 children in Bangui (Central African Republic). Each child received two doses of either placebo (235 children) or vaccine (237 children) at a 1-month interval, the first dose being given at 3 months of age. During the follow-up survey 9 months after the first dose, 117 rotavirus diarrhoeas were observed, 59 in the placebo group, 58 in the vaccinated group. The only positive effect of the vaccine was a significantly higher proportion of mild rotavirus diarrhoeal episodes in the vaccinated group than in the placebo group. Of the children in the vaccinated group, 60% had a positive immune response to WC3 rotavirus when tested by plaque reduction seroneutralization.

Morbidite et mortalite dans le service de pediatrie de Bangui (Centrafrique) au cours de l'annee 1990 : implications en matiere de sante publique

Le bilan d'une annee d'hospitalisations (morbidite-mortalite) dans le Service de Pediatrie de Bangui en Republique Centrafricaine est presente. 8052 enfants ont ete hospitalises dans l'annee 1990 et le taux de mortalite hospitaliere globale est de 11;6 pour cent. Les deces sont precoces et frappent surtout les enfants de moins d'un an. Parmi les pathologies recensees les auteurs insistent particulierement sur l'importance et la gravite croissante du paludisme et des anemies severes dans le jeune age. Le service concerne est la seule structure hospitalisant des enfants dans la region; ainsi les statistiques presentees peuvent constituer un reflet de la pathologie locale et etre utilisees pour l'orientation des decisions en matiere de sante publique