Expanded programme on immunization (EPI). Safety of high titre measles vaccines

Unexpected results suggesting decreased survival when compared with standard titre vaccine administered at 9 months of age have been found in some field studies evaluating the performance of high titre measles vaccine. Analytical difficulties have arisen because the studies were not specifically designed to measure survival. Nonetheless, careful analysis of the results from all of the high titre vaccine trials showed decreased survival of high titre vaccine recipients, in areas with high background mortality rates, compared with recipients of standard measles vaccines at 9 months. No systematic biases could be found in the studies to explain these differences. Statistical analysis of these data suggested that the findings were unlikely to be attributable to chance alone. The panel recommended that high titre measles vaccine derived from the original Edmonston measles vaccine isolate should no longer be recommended for use in immunization programmes. Further post-licensure field studies of new measles vaccines should take into account the results of these studies. Additional detailed epidemiological studies in populations that have received high titre vaccines and their controls were encouraged.

Prevention of blood-borne HIV transmission using a decentralized approach in Shaba, Zaire

OBJECTIVE

To prevent blood transfusion-acquired HIV infection with a decentralized approach to HIV screening of blood donors, using an instrument-free rapid test.

SETTING

Shaba province, Zaire (496,877 km2).

METHODS

The programme consisted of training health-care workers, distribution of a rapid HIV-antibody test (DuPont's HIVCHEK) for screening of all blood donations, and quality control of testing by a regional reference centre.

RESULTS

Over a 2-year period, 11,940 rapid tests were distributed to 37 hospitals, covering 75% of all hospital beds outside the copper mine's health system in Shaba. Eighty-five per cent of the tests were used to screen blood donors (5.4% positive test rate) and 13% to test patients (39.7% positive test rate). At least 265 cases of HIV-positive blood donation were prevented, at an estimated cost of 137-279 ECU per case. Only 26% of initially positive specimens reached the central laboratory for supplemental testing, and sterile transfusion equipment and blood-grouping reagents were frequently unavailable. The lack of transport and communications and a deteriorating health system were major constraints.

CONCLUSIONS

District hospitals in Africa are often long distances from major cities, difficult to reach for most of the year, and perform a small number of transfusions. In this context a classical centralized regional blood bank may not be a feasible option to ensure safe blood transfusions. However, safe blood transfusion can be achieved with a decentralized approach using a rapid test, provided that minimum standards of health-care services are available.

Relationships between circulating S-antigens, naturally acquired antibodies to Plasmodium falciparum exoantigens and malaria attack in a mesoendemic area

A survey involving 77 individuals living in two savannah villages near Bobo Dioulasso (Burkina Faso, West Africa), was performed in June 1987 (before), August-September (during) and January 1988 after the seasonal transmission. The clinical longitudinal study during the seasonal period permitted us to define three different groups in terms of both age and occurrence of malaria attack (MA; greater than or equal to 5000 parasites/mm3 of blood and axillary fever greater than or equal to 37.8 degrees C). The presence of circulating stable antigen (S-Ag) and the antibody responses against exoantigens (E-Ag) of Plasmodium falciparum were also evaluated at three observations periods: beginning, during and after the transmission season. The adult group (III) had the highest rates of IgG Ab to E-Ag although, IgM prevalence to E-Ag was maximal in the group II (individuals with no malaria attack and age less than or equal to 15 years old). Group I (persons with less than or equal to 15 years old and who contracted at least one MA) did not have any S-Ag at the first observation period and showed the lowest rate of antibodies to E-Ag. The probability of occurrence of an MA calculated from these parameters at the beginning of the transmission period were correct in 78.9% of the cases in children (Groups I & II) and in 71.8% of adults during the subsequent transmission period. Therefore these values could be used for evaluating the probability of occurrence of a clinical MA during the transmission period in a mesoendemic area. S-Ag and antibodies to E-Ag could participate positively in the mechanisms involved in the development of the immune status.

World Health Organization clinical case definition for AIDS in Africa: an analysis of evaluations

In 1985 at a World Health Organization (WHO) workshop on AIDS in Bangui, Central African Republic, a clinical case definition of Acquired Immune Deficiency Syndrome (AIDS) was developed for developing countries, such as sub-Saharan Africa, where sophisticated diagnostic equipment is not widely available. A particular cachectic syndrome, the "slim disease", which is highly suggestive of AIDS in Africa, constitutes the substratum for the clinical definition for AIDS. The WHO/Bangui definition in adults has a sensitivity of 60%, a specificity of 90%, and a high predictive value especially in endemic areas. The WHO/Bangui clinical case definition for paediatric AIDS is less easy to use in practice. Its low sensitivity (about 35%) is in relation to its incapacity to diagnose many of the frequently observed secondary infection for paediatric AIDS according to the CDC criteria. The WHO/Bangui clinical definition for AIDS seems to be convenient for epidemiological surveillance of the HIV epidemic in Africa. Nevertheless, the low sensitivity and the low specificity result in the failure to detect some cases of full blown AIDS.

Prevalence and risk determinants of human immunodeficiency virus type 2 (HIV-2) and human immunodeficiency virus type 1 (HIV-1) in west African female prostitutes

The authors studied the prevalence and risk determinants for human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) in female prostitutes from Dakar (1985-1990), Ziguinchor (1987-1990), and Kaolack (1987-1990), Senegal, West Africa. Each cohort showed a distinct distribution of HIVs: 10.0% HIV-2 and 4.1% HIV-1 in Dakar, 38.1% HIV-2 and 0.4% HIV-1 in Ziguinchor, and 27.4% HIV-2 and 1.3% HIV-1 in Kaolack. In 1,275 female prostitutes from Dakar, increase years of sexual activity and a history of scarification were associated with HIV-2 seropositivity. In contrast, HIV-1 seroprevalence was associated with a shorter duration of prostitution and a history of hospitalization. In 278 female prostitutes from Ziguinchor, HIV-2 seroprevalence was associated with women of Guinea-Bissau nationality and increased years of sexual activity. In 157 female prostitutes from Kaolack, HIV-2 seroprevalence was associated with increased years of sexual activity and a history of never using condoms. The authors also studied the risk determinants for HIV-2 in the 1,280 Senegalese prostitutes pooled from all three sites. Controlling for ethnic group, women from Ziguinchor and Kaolack were more likely to be HIV-2 seropositive as compared with women from the Dakar site. Increased years of sexual activity were associated with HIV-2 seropositivity, while a history of excision and BCG vaccinations decreased the risk of HIV-2 infection.

Diagnostic challenges: lymphotropic sero-"questionables"

During a sero-survey for lymphotropic retroviruses, seven screening tests were performed for the three lymphotropic retroviruses of relevance in Djibouti, East Africa (HIV-1, HIV-2 and HTLV-1). Of the 82 subjects whose sera reacted in at least one retroviral screening assay, about one third could be followed, and their sera were re-examined after a 5-month interval, and then after an additional 3-month interval. Six selected individuals are reported here, whose retroviral serologies presented important and often unexplained changes over an eight-month period. The six cases summarize prototypic situations and present serological results in a style appropriate to stimulate thought on the significance and interpretation of lymphotropic viral serologies. Each case study is followed by a set of questions that formulate pertinent serological concepts.

[Management of malnourished children. Cases from the Protestant Hospital of Dabou]

Malnutrition due to lack of nutritional resources unfortunately remains an endemic which ravages Third World countries. Not only is malnutrition a result of continuous droughts and wars, but it is a reflection of the difficult economic circumstances which persist in these countries. Malnutrition should be specifically treated in each region with the least costly locally available means. The experience of the Protestant Hospital of Dabou proves that this manner of care is possible in the midst of a rural area with very limited resources. Hospital surveillance, nutritional education and a stay in the nutritional rehabilitation center offers these malnourished children a new chance to begin in life again. Unfortunately for some, the acquired benefits disappear once they have left the establishment and the child returns to the same least favorable socio-economic environment for his development.

Risk of human immunodeficiency virus type 1 transmission through breastfeeding

Detection of human immunodeficiency virus type 1 (HIV-1) in breast milk by culture and polymerase chain reaction does not necessarily mean that breastfeeding is a route of transmission, although evidence from several case-reports points in that direction. We undertook a systematic review of published studies meeting criteria that allowed determination of quantitative risk of transmission via breastfeeding. Based on four studies in which mothers acquired HIV-1 postnatally, the estimated risk of transmission is 29% (95% Cl 16-42%). Analysis of five studies showed that when the mother was infected prenatally, the additional risk of transmission through breastfeeding, over and above transmission in utero or during delivery, is 14% (95% Cl 7-22%). Where there are safe alternatives to breastfeeding, universal named testing of pregnant women would provide an opportunity to advise more infected women not to breastfeed and might thereby reduce the number of vertically infected children. Since breastfeeding protects against infant deaths from infectious diseases, breastfeeding is still recommended where infectious diseases are a common cause of death in childhood, despite the additional risk of HIV transmission.

HIV-2 infections in a rural Senegalese community

In a community study in rural Senegal, 22 human immunodeficiency virus type-2 (HIV-2) seropositive cases and 64 matched controls were examined clinically and evaluated immunologically. The presence of clinical signs was highly correlated with HIV-2 seropositivity: 9 anti-HIV-2 positive patients and 5 controls presented with clinical signs (odd ratio [OR] = 8.2, confidence limits [CL] 2-35). The main symptom associated with HIV-2 seropositivity was a chronic cough (OR = 18.5, CL 1.8-899). The presence of diarrhoea was not significant (OR = 3.1, CL 0.3-3.5). The total number of CD8 cells, CD4/CD8 ratio, beta 2 microglobulin, and IgG level discriminated between seropositive and seronegative individuals (P less than 0.05). When the anti-HIV-2 positives were grouped as 13 healthy and 9 sick people, red blood cells, lymphocytes, T lymphocytes, CD4 cells, and beta 2 microglobulin differed significantly. Clinical symptoms were associated with immunodepression: 5 of 14 sick people had less than 500 CD4/microliters vs. 1 of 72 healthy persons. This study at the community level emphasizes the clinical and immunological impact of HIV-2 infection. Even if it presents with a longer incubation period than HIV-1, this virus is a major threat to public health.

Infant and child mortality and malaria in the Congo. The trend in the suburbs of Brazzaville between 1981 and 1988

This survey was carried out on a cohort of children born between 1st January 1981 and 30th June 1987 in the maternity department of the hospital in Linzolo, a village situated 25 km south-west of Brazzaville, the capital of the Congo. The mothers of the children resided in the suburbs of Brazzaville at the time of delivery. In this region, the rate of transmission of Plasmodium falciparum malaria is high without marked seasonable variations. The mothers and children were traced in the second quarter of 1989 in order to assess the rates and, where possible, the causes of mortality. Information on 75% of the recorded births (2424 children) was obtained directly by interviewing the mothers in the home. Between 1981 and 1988, the infant mortality rate varied overall between 33 and 52 per thousand, and in the 1-2 year age group, between 7 and 25 per thousand (1981 to 1987). The number of deaths attributable to malaria was relatively low although resistance to amino-4-quinolone is well established since 1985. During this period, no particular trend was observed in the mortality at 0-2 years, or at 0-5 years.

Malaria and pregnancy in Cameroonian women. Naturally acquired antibody responses to asexual blood-stage antigens and the circumsporozoite protein of Plasmodium falciparum

Antibody responses to Plasmodium falciparum antigens in women during pregnancy were investigated in Mfou, a rural community in Cameroon. The study consisted of cross-sectional analyses involving 225 pregnant women and 75 non-pregnant controls. Blood samples were collected from each woman to determine serological reactivity to intraerythrocytic malarial antigens, ring-infected erythrocyte surface antigen (RESA) and circumsporozoite (CS) repeat peptide (NANP)5 by the indirect fluorescent antibody assay, modified immunofluorescent antibody assay, and enzyme-linked immunosorbent assay, respectively. Reactivity to intraerythrocytic asexual blood-stage antigens and to the CS repeat region was similar in both pregnant and non-pregnant women, and no correlation with parasitaemia was found. In contrast, anti-RESA antibody levels were significantly lower in pregnant than in non-pregnant women (P = 0.02) and in primigravidae than in multigravidae (P = 0.002), and were inversely correlated with parasitaemia (r = -0.36; P < 0.01). These data suggest that the increased susceptibility to malarial infection in pregnant women may be explained in part by their lower reactivity to RESA.

Consequences of Schistosoma haematobium infection on the iron status of schoolchildren in Niger

The relationship between iron status and degree of infection by Schistosoma haematobium was studied in 174 schoolchildren from Niger in an area endemic for urinary schistosomiasis. Iron deficiency was defined by a combination of three reliable indicators: a low serum ferritin level combined with a low transferrin saturation, a high erythrocyte protoporphyrin level, or both. Hematuria and proteinuria were found in 76.4% and 79.9% of the children, respectively, while 95.4% excreted eggs (geometric mean egg count of 31.5 eggs per 10 ml of urine). Anemia was observed in 59.7% of the subjects. The prevalence of iron deficiency was 47.1%. Anemia was associated with iron deficiency in 57.7% of the cases. The hemoglobin level and transferrin saturation decreased significantly when the degree of hematuria increased, while prevalence of anemia and prevalence of iron deficiency increased significantly. The hemoglobin level and the hematocrit were negatively correlated with egg count, while prevalence of anemia increased with increasing egg count. This inverse relationship between degree of infection by S. haematobium and iron status shows a deleterious consequence of urinary schistosomiasis on nutrition and hematopoietic status, which should be considered in the design of nutrition intervention programs.

Risk of HIV infection from transfusion with blood negative for HIV antibody in a west African city

OBJECTIVE

To estimate the risk of infection with HIV (HIV 1 or HIV 2, or both) from transfusion of a screened unit of blood in a high prevalence area in west Africa.

DESIGN

Retrospective cohort study for January-July 1991.

SETTING

National Blood Transfusion Centre, Abidjan, Côte d'Ivoire.

SUBJECTS

Repeat donors (5831 units of blood) and first time donors (5076 units) in the first five months of 1991.

MAIN OUTCOME MEASURES

Prevalence and estimated incidence of HIV infection in repeat and first time donors; estimated rate of potentially infected, HIV antibody negative units; and rate of (false negative) potentially infected units assuming a laboratory test sensitivity of 99%.

RESULTS

Overall HIV prevalence was 11.0% in first time donors and 2.1% in repeat donors. In the first seven months of 1991, 29 HIV antibody positive (27 HIV 1, 1 HIV 2, 1 dually reactive) donors with a seronegative unit of blood earlier in the year were identified; 26 had donated blood eight weeks or less before their estimated dates of seroconversion and may have been infectious (minimum rate 26/5831 (4.5/1000 potentially infected units)). Estimated incidence of infection in repeat donors was 1.2-2.5%. Laboratory test insensitivity would result in an estimated 1.1/1000 false negative units from first time donors and 0.2/1000 units from regular donors. The overall rate of potentially infected units (all donors, seroconversions, and errors) was estimated at 5.4-10.6/1000.

CONCLUSIONS

The risk of HIV infection from a single unit of blood remains substantial (5.4-10.6/1000 units). To prevent infection from blood transfusion in areas of high incidence and prevalence of HIV all but absolutely essential transfusions should be avoided, and donors with low incidence of HIV infection should be selected.

Influence of cross-sex transmission on measles mortality in rural Senegal

Previous studies of measles mortality in West Africa have shown a significantly higher case-fatality rate (CFR) among girls than among boys. This study aimed to find out whether the male/female difference in CFR is related to different risks for boys and girls of being infected as secondary rather than index cases and of transmission from someone of the same or the opposite sex. The study was conducted in Niakhar, a rural area of Senegal (population 24,000). All cases of measles reported between March, 1983, and December, 1986, were investigated to determine source of infection and pattern of transmission. For each case, the closest source of infection was judged the most likely. Death was attributed to measles if it occurred within 6 weeks of the onset of rash. Girls had a higher measles CFR than boys (53 deaths/722 cases [7.3%] vs 45/778 [5.8%]); the relative risk of death was 1.30 (95% confidence interval [CI] 0.89-1.90). Secondary cases infected by a child of the opposite sex had a 2.44 (1.48-4.02) times higher risk of death than did secondary cases infected by a child of the same sex. The risk of cross-sex transmission of infection was significantly greater for female than for male secondary cases (1.26 [1.09-1.47]). When this difference in risk of exposure to infection from the opposite sex was taken into account, the difference in risk of death between girls and boys disappeared (1.06 [0.66-1.69]). Within families, the CFR was higher in huts with 1 boy and 1 girl affected than in huts of either 2 boys or 2 girls affected (relative risk 2.16 [0.99-4.70]). Measles infection contracted from a person of the opposite sex is more severe. Variation in exposure may be an important determinant of sex differences in case fatality.

Communication key for family planning

4 reports published by Demographic and Health Surveys (DHS) include information from husbands of the wives interviewed in the main part of the survey. All are from Africa--Burundi (1987), Ghana (1988), Kenya (1988) and Mali (1987). These surveys of husbands indicate the importance of programs that work to improve communication between spouses about family planning. In particular, they show a positive association between contraceptive prevalence and husband and wife communication about family planning. Husbands and wives were asked how often they discussed family planning in the past year. In Kenya, with a 27% contraceptive prevalence rate--the highest among the 4 countries--about 2/3 of the couples had discussed family planning during the past year. In Ghana, with a rate of 13%, and in Burundi, at 9%, about 1.2 of the couples had discussed family planning during the year. Mali had the lowest contraception prevalence rate of 5% and the least communication among the couples, with only 1.4 discussing family planning during the year. The importance of communication also emerges in data on methods used. In all 4 surveys, the wives reported lower use of male methods than did their husbands. Estimates of use of female methods were more consistent between husbands and wives. Questions were not exactly the same in all 4 surveys, so summaries for each country vary slightly. In Burundi, about 2 of 5 husbands said they used periodic abstinence, compared to about 1 of 5 wives. Husbands said 0.7% used condoms, with 0.3% of the wives giving that response. Husbands an wives agreed that there was no use of male sterilization. The use of vasectomy in Africa is considerably lower than for other regions of the world (see chart below). Ghana showed a similar pattern. Husbands said 2.1% of couples used condoms, compared to 0.3% according to the wives. Husbands also indicated more widespread use of periodic abstinence than did the wives. In contrast, except for pill use, husbands and wives gave similar responses for use of female methods. In Kenya, 1 of every 2 husbands said they were using family planning, compared to about 1 of every 4 wives. The largest discrepancy was in the data for use of periodic abstinence, where 3 times more husbands than wives said they were using this method--26% compared to 8%. Only in Mali, where total contraceptive use is only 5%, were responses from husbands and wives consistent. Even here, husbands gave higher rates of condom use (0.5%) than did wives (none). When it comes to choosing a method of family planning, women apparently think first of female methods. In general, women assume that their husbands will not be interested in using contraception themselves. Women may, however, underestimate their husbands interest or participation in family planning. Or men could be overstating the use of male methods. These DHS husband surveys suggest that programs aimed at both men and women should encourage more and better communication between spouses about family planning. More data related to communication on family planning will soon become available. Other DHS husbands surveys in various stages of completion are from Pakistan, Cameroon, Tanzania, and Egypt.