Effect of an Early Dose of Measles Vaccine on Morbidity Between 18 Weeks and 9 Months of Age: A Randomized, Controlled Trial in Guinea-Bissau.

Background: Children in Guinea-Bissau receive measles vaccine (MV) at 9 months of age, but studies have shown that an additional dose before 9 months of age might have beneficial nonspecific effects. Within a randomized trial designed to examine nonspecific effects of early MV receipt on mortality, we conducted a substudy to investigate the effect of early MV receipt on morbidity. Methods: Children were randomly assigned at a ratio of 2:1 to receive 2 doses of MV at 18 weeks and age 9 months (intervention group) or 1 dose of MV at age 9 months, in accordance with current practice (control group). Children were visited weekly from enrollment to age 9 months; the mother reported morbidity, and the field assistants examined the children. Using Cox and binomial regression models, we compared the 2 randomization groups. Results: Among the 1592 children, early measles vaccination was not associated with a higher risk of the well-known adverse events of fever, rash, and convulsions within the first 14 days. From 15 days after randomization to age 9 months, early measles vaccination was associated with reductions in maternally reported diarrhea (hazard ratio [HR], 0.89; 95% confidence interval [CI], .82-.97), vomiting (HR, 0.86; 95% CI, .75-.98), and fever (HR, 0.93; 95% CI, .87-1.00). Conclusion: Early MV receipt was associated with reduced general morbidity in the following months, supporting that early MV receipt may improve the general health of children.

A randomized trial of a standard dose of Edmonston-Zagreb measles vaccine given at 4.5 months of age: effect on total hospital admissions.

Observational studies and trials from low-income countries indicate that measles vaccine has beneficial nonspecific effects, protecting against non-measles-related mortality. It is not known whether measles vaccine protects against hospital admissions. Between 2003 and 2007, 6417 children who had received the third dose of diphtheria, tetanus, and pertussis vaccine were randomly assigned to receive measles vaccine at 4.5 months or no measles vaccine; all children were offered measles vaccine at 9 months of age. Using hospital admission data from the national pediatric ward in Bissau, Guinea-Bissau, we compared admission rates between enrollment and the 9-month vaccination in Cox models, providing admission hazard rate ratios (HRRs) for measles vaccine versus no measles vaccine. All analyses were conducted stratified by sex and reception of neonatal vitamin A supplementation (NVAS). Before enrollment the 2 groups had similar admission rates. Following enrollment, the measles vaccine group had an admission HRR of 0.70 (95% confidence interval [CI], .52-.95), with a ratio of 0.53 (95% CI, .32-.86) for girls and 0.86 (95% CI, .58-1.26) for boys. For children who had not received NVAS, the admission HRR was 0.53 (95% CI, .34-.84), with an effect of 0.30 (95% CI, .13-.70) for girls and 0.73 (95% CI, .42-1.28) for boys (P = .08, interaction test). The reduction in admissions was separately significant for measles infection (admission HRR, 0 [95% CI, 0-.24]) and respiratory infections (admission HRR, 0.37 [95% CI, .16-.89]). Early measles vaccine may have major benefits for infant morbidity patterns and healthcare costs. Clinical trials registration NCT00168558.

Weight change in the first 30 days among infants born less than 2000 grams in Guinea-Bissau and Uganda.

Despite the high prevalence of low birth weight infants in sub-Saharan Africa and the associated poor outcomes, weight change during the newborn period has not been well characterized for this population. We prospectively assessed growth over the first 30 days among 120 infants born < 2000 g (g) in Guinea-Bissau and Uganda, and compared it to a similar cohort of 420 infants born ≥ 2000 g. Among those born < 2000 g, mean birth weight was 1747 ± 164 g, and initial weight loss was 8.25 ± 4.40% of birth weight prior to the initiation of weight gain at a median of 3 (interquartile range 2, 4) days of age. This initial weight loss was more pronounced (8.25 vs 6.06%; p < 0.001) and lasted longer (median 3 vs 2 days; p < 0.001) than for infants born ≥ 2000 g. The initial period of weight loss was an important predictor of growth at 30 days in both cohorts. Infants born < 2000 g on average grew proportionately to their size at birth but did not experience catch-up growth; their weights at 30 days remained much lower than that of infants born ≥ 2000 g and most remained severely underweight. Targeted interventions to optimize early growth should be investigated.

Breastfeeding and Once-Daily Small-Volume Formula Supplementation to Prevent Infant Growth Impairment.

BACKGROUND: Randomized controlled trials in Guinea-Bissau and Uganda have revealed that the intensive promotion of exclusive breastfeeding (EBF) impairs growth in early infancy. When newborn growth is impaired, small amounts of formula may be combined with breastfeeding to promote growth. METHODS: To determine if breastfeeding combined with once-daily formula supplementation improves growth among at-risk newborns, we conducted a pilot randomized controlled trial in Bissau, Guinea-Bissau and Kampala, Uganda. We randomly assigned 324 healthy breastfeeding newborns who weighed 2000 g to 2499 g at birth or <2600 g at 4 days old to once-daily formula feeding through 30 days as a supplement to frequent breastfeeding followed by EBF from 31 days through 6 months, or to EBF through 6 months. The primary outcome was weight-for-age z score (WAZ) at 30 days. Other outcomes included weight-for-length z score (WLZ), length-for-age z score (LAZ), breastfeeding cessation, adverse events, and serious adverse events through 180 days. RESULTS: Daily formula consumption in the intervention group was 31.9 ± 11.8 mL. The random assignment did not impact WAZ, WLZ, LAZ, breastfeeding cessation, adverse events, or serious adverse events through 180 days. In the intervention and control groups, 19 (12%) and 35 (21%) infants, respectively, reported nonformula supplementation in the first 30 days (P = .02). CONCLUSIONS: Once-daily formula supplementation for 30 days was well-tolerated, but the small volume consumed did not alter growth through 180 days of age. Further research would be required to determine if larger formula volumes, longer duration of treatment, or more frequent feeding are effective at increasing growth for this at-risk population.

Effects of food supplementation on cognitive function, cerebral blood flow, and nutritional status in young children at risk of undernutrition: randomized controlled trial.

OBJECTIVE: To assess the effects of food supplementation on improving working memory and additional measures including cerebral blood flow in children at risk of undernutrition. DESIGN: Randomized controlled trial. SETTING: 10 villages in Guinea-Bissau. PARTICIPANTS: 1059 children aged 15 months to 7 years; children younger than 4 were the primary population. INTERVENTIONS: Supervised isocaloric servings (≈1300 kJ, five mornings each week, 23 weeks) of a new food supplement (NEWSUP, high in plant polyphenols and omega 3 fatty acids, within a wide variety and high fortification of micronutrients, and a high protein content), or a fortified blended food (FBF) used in nutrition programs, or a control meal (traditional rice breakfast). MAIN OUTCOME MEASUREMENTS: The primary outcome was working memory, a core executive function predicting long term academic achievement. Additional outcomes were hemoglobin concentration, growth, body composition, and index of cerebral blood flow (CBFi). In addition to an intention-to-treat analysis, a predefined per protocol analysis was conducted in children who consumed at least 75% of the supplement (820/925, 89%). The primary outcome was assessed by a multivariable Poisson model; other outcomes were assessed by multivariable linear mixed models. RESULTS: Among children younger than 4, randomization to NEWSUP increased working memory compared with the control meal (rate ratio 1.20, 95% confidence interval 1.02 to 1.41, P=0.03), with a larger effect in the per protocol population (1.25, 1.06 to 1.47, P=0.009). NEWSUP also increased hemoglobin concentration among children with anemia (adjusted mean difference 0.65 g/dL, 95% confidence interval 0.23 to 1.07, P=0.003) compared with the control meal, decreased body mass index z score gain (-0.23, -0.43 to -0.02, P=0.03), and increased lean tissue accretion (2.98 cm2, 0.04 to 5.92, P=0.046) with less fat (-5.82 cm2, -11.28 to -0.36, P=0.04) compared with FBF. Additionally, NEWSUP increased CBFi compared with the control meal and FBF in both age groups combined (1.14 mm2/s×10-8, 0.10 to 2.23, P=0.04 for both comparisons). Among children aged 4 and older, NEWSUP had no significant effect on working memory or anemia, but increased lean tissue compared with FBF (4.31 cm2, 0.34 to 8.28, P=0.03). CONCLUSIONS: Childhood undernutrition is associated with long term impairment in cognition. Contrary to current understanding, supplementary feeding for 23 weeks could improve executive function, brain health, and nutritional status in vulnerable young children living in low income countries. Further research is needed to optimize nutritional prescriptions for regenerative improvements in cognitive function, and to test effectiveness in other vulnerable groups. TRIAL REGISTRATION: ClinicalTrials.gov NCT03017209.

Thymus size at 6 months of age and subsequent child mortality.

OBJECTIVE: To examine determinants of thymus size at age 6 months and investigate whether thymus size at this age is a determinant of subsequent mortality. STUDY DESIGN: Thymus size was measured by transsternal sonography in 923 6-month-old children participating in a measles vaccination trial in Guinea-Bissau. RESULTS: Thymus size was strongly associated with anthropometric measurements. Boys had larger thymuses than girls, controlling for anthropometry. Crying during sonography made the thymus appear smaller. Children who were not vaccinated with Bacille Calmette-Guérin (BCG) or were vaccinated with BCG in the preceding 4 weeks before inclusion into the study had larger thymuses. Children who had malaria or had been treated with chloroquine or Quinimax in the previous week before inclusion had smaller thymuses. Controlled for background factors associated with thymus size and mortality, small thymus size remained a strong and independent risk factor for mortality (hazard ratio = 0.31; 95% confidence interval = 0.18 to 0.52). CONCLUSIONS: Small thymus size at age 6 months is a strong risk factor for mortality. To prevent unnecessary deaths, it is important to identify preventable factors predisposing to small thymus size.

Nutrition Status of Primary School Students in Two Rural Regions of Guinea-Bissau.

BACKGROUND: The nutrition status of primary schoolchildren in Africa has received relatively little attention in comparison to that of younger children. We surveyed primary school students in Guinea-Bissau, a nation that is among the poorest in the world. OBJECTIVE: Anthropometry and prevalence of anemia and vitamin A deficiency were assessed in schoolchildren participating in International Partnership for Human Development's school feeding program in 2 regions of Guinea-Bissau. METHODS: A cross-sectional survey of 32 schools in the regions of Cacheu and Oio was conducted in November 2011. Variables included age, gender, weight, height, hemoglobin, and retinol-binding protein concentrations. Z scores for height for age (HAZ), body mass index for age (BAZ), and weight for age were calculated using World Health Organization reference data. RESULTS: Anthropometric assessment of 4784 students revealed stunting (HAZ < -2) in 15.5%, thinness (BAZ < -2) in 13.2%, and anemia in 42.0%. Stunting, thinness, and anemia were significantly more common in males, in students from Oio, and in older students. Vitamin A deficiency, detected in 21.5% of the population, was the only assessment that did not demonstrate significant differences between genders or regions. About 61.1% of all children had 1 or more indicators of undernutrition. CONCLUSION: There are substantial rates of stunting, thinness, underweight, anemia, and vitamin A deficiency in primary schoolchildren in Guinea-Bissau, even among those participating in a school lunch program and particularly among males and older students. The results suggest the need for evaluating feeding programs and other methods to improve nutrition status in primary school students, especially in older students.

Seasonal and sex-specific variations in haematological parameters in 4 to 5.5-month-old infants in Guinea-Bissau, West Africa.

Objective: This study investigated seasonal and sex-specific variations in the haematological parameters and established reference ranges for these parameters in healthy 4 to 5.5-month-old infants in Guinea-Bissau. Methods: Within a randomised trial of early measles vaccination, over a period of 13 months blood samples were collected from infants aged 4 to 5.5 months. Haematological parameters were determined by an automated cell counter and compared in linear regression models providing geometric mean ratios (GMR). Results: Blood samples from 501 infants (n=248 boys, 49.5%) were obtained, and 285 (56.9%) were collected in the rainy season. Median age was 4.7 months (range 3.7 to 7.2 months). Eosinophil and platelet counts were lower in the dry season (December to May) than in the rainy season (GMR 0.79 [95% CI 0.68-0.92]) and 0.93 [0.87-1.00], respectively). The calculated reference ranges were wider and generally higher than those from a US population of comparable age, but neutrophil levels were notably lower in Guinea-Bissau. Conclusions: The study indicated that eosinophil and platelet counts of infants were subject to seasonal variations. The reference ranges for haematological values were comparable to other African populations and corroborated that neutropenia regularly occurs in African infants.

A Randomized Controlled Trial of Two Ready-to-Use Supplementary Foods Demonstrates Benefit of the Higher Dairy Supplement for Reduced Wasting in Mothers, and Differential Impact in Infants and Children Associated With Maternal Supplement Response.

BACKGROUND: There is no consensus over best approaches to reliably prevent malnutrition in rural communities in low-income countries. OBJECTIVE: We compared the effectiveness of 2 lipid-based ready-to-use supplementary foods (RUSFs) differing in dairy protein content to improve the nutritional status of mothers and at-risk infants and young children in rural Guinea-Bissau. METHODS: A 3-month cluster-randomized controlled pilot trial of 2 RUSFs was conducted with 692 mothers and 580 mildly or moderately malnourished infants (6-23 months) and children (24-59 months) from 13 villages. The RUSFs contained either 478 (mothers, children) or 239 kcal/d (infants) with 15% or 33% of protein from dairy and were distributed at community health centers 5 d/wk. Controls were wait-listed to receive RUSF. Primary outcomes were mid-upper arm circumference (MUAC) in mothers, and weight-for-age and height-for-age z-scores (WAZ and HAZ) in infants and children. RESULTS: There was a significant effect of the RUSF-33% on MUAC in mothers ( P = .03). The WAZ and HAZ increased substantially, by ≈1 z-score, in infants and children ( P < .01) independent of group randomization. In children, but not infants, baseline WAZ and change in maternal MUAC were associated with change in WAZ (ß = .07, P = .02). CONCLUSION: Ready-to-use supplementary foods with higher dairy protein content had a significant benefit in village mothers, supporting a comparable recent finding in preschool children. In addition, supplementation of children <2 years resulted in improved growth independent of family nutritional status, whereas success in older children was associated with change in maternal nutrition, suggesting the need for community-level education about preventing malnutrition in older, as well as younger, children.

A Pilot Randomized Controlled Trial of a New Supplementary Food Designed to Enhance Cognitive Performance during Prevention and Treatment of Malnutrition in Childhood.

BACKGROUND: Cognitive impairment associated with childhood malnutrition and stunting is generally considered irreversible. OBJECTIVE: The aim was to test a new nutritional supplement for the prevention and treatment of moderate-acute malnutrition (MAM) focused on enhancing cognitive performance. METHODS: An 11-wk, village-randomized, controlled pilot trial was conducted in 78 children aged 1-3 or 5-7 y living in villages in Guinea-Bissau. The supplement contained 291 kcal/d for young children and 350 kcal/d for older children and included 5 nutrients and 2 flavan-3-ol-rich ingredients not present in current food-based recommendations for MAM. Local bakers prepared the supplement from a combination of locally sourced items and an imported mix of ingredients, and it was administered by community health workers 5 d/wk. The primary outcome was executive function abilities at 11 wk. Secondary outcomes included additional cognitive measures and changes in z scores for weight (weight-for-age) and height (height-for-age) and hemoglobin concentrations at 11 wk. An index of cerebral blood flow (CBF) was also measured at 11 wk to explore the use of this measurement as a biological index of cognitive impairment. RESULTS: There were no significant differences in any outcome between groups at baseline. There was a beneficial effect of random assignment to the supplement group on working memory at 11 wk in children aged 1-3 y (P < 0.05). This difference contrasted with no effect in older children and was not associated with faster growth rate. In addition, CBF correlated with task-switching performance (P < 0.05). CONCLUSIONS: These preliminary data suggest that cognitive impairment can be monitored with measurement of CBF. In addition, the findings provide preliminary data that suggest that it may be possible to improve poor cognitive performance in young children through changes in the nutritional formulation of supplementary foods used to prevent and treat MAM. Powered studies of the new supplement formulation are needed. This trial was registered at clinicaltrials.gov as NCT03017209.

Co-administration of live measles and yellow fever vaccines and inactivated pentavalent vaccines is associated with increased mortality compared with measles and yellow fever vaccines only. An observational study from Guinea-Bissau.

BACKGROUND: Studies from low-income countries indicate that co-administration of inactivated diphtheria-tetanus-pertussis (DTP) vaccine and live attenuated measles vaccine (MV) is associated with increased mortality compared with receiving MV only. Pentavalent (DTP-H. Influenza type B-Hepatitis B) vaccine is replacing DTP in many low-income countries and yellow fever vaccine (YF) has been introduced to be given together with MV. Pentavalent and YF vaccines were introduced in Guinea-Bissau in 2008. We investigated whether co-administration of pentavalent vaccine with MV and yellow fever vaccine has similar negative effects. METHODS: In 2007-2011, we conducted a randomised placebo-controlled trial of vitamin A at routine vaccination contacts among children aged 6-23 months in urban and rural Guinea-Bissau. In the present study, we included 2331 children randomised to placebo who received live vaccines only (MV or MV+YF) or a combination of live and inactivated vaccines (MV+DTP or MV+YF+pentavalent). Mortality was compared in Cox proportional hazards models stratified for urban/rural enrolment adjusted for age and unevenly distributed baseline factors. RESULTS: While DTP was still used 685 children received MV only and 358 MV+DTP; following the change in programme, 940 received MV+YF only and 348 MV+YF+pentavalent. During 6 months of follow-up, the adjusted mortality rate ratio (MRR) for co-administered live and inactivated vaccines compared with live vaccines only was 3.24 (1.20-8.73). For MV+YF+pentavalent compared with MV+YF only, the adjusted MRR was 7.73 (1.79-33.4). CONCLUSION: In line with previous studies of DTP, the present results indicate that pentavalent vaccine co-administered with MV and YF is associated with increased mortality.

High-dose vitamin A with vaccination after 6 months of age: a randomized trial.

BACKGROUND: The World Health Organization recommends vitamin A supplementation (VAS) at routine vaccination contacts after 6 months of age based on the assumption that it reduces mortality by 24%. The policy has never been evaluated in randomized controlled trials for its effect on overall mortality. We conducted a randomized double-blind trial to evaluate the effect of VAS with vaccines. METHODS: We randomized children aged 6 to 23 months 1:1 to VAS (100000 IU if aged 6-11 months, 200000 IU if aged 12-23 months) or placebo at vaccination contacts in Guinea-Bissau. Mortality rates were compared in Cox proportional-hazards models overall, and by gender and vaccine. RESULTS: Between August 2007 and November 2010, 7587 children were enrolled. Within 6 months of follow-up 80 nonaccident deaths occurred (VAS: 38; placebo: 42). The mortality rate ratio (MRR) comparing VAS versus placebo recipients was 0.91 (95% confidence interval 0.59-1.41) and differed significantly between boys (MRR 1.92 [0.98-3.75]) and girls (MRR 0.45 [0.24-0.87]) (P = .003 for interaction between VAS and gender). At enrollment, 42% (3161/7587) received live measles vaccine, 29% (2154/7587) received inactivated diphtheria-tetanus-pertussis-containing vaccines, and 21% (1610/7587) received both live and inactivated vaccines. The effect of VAS did not differ by vaccine group. CONCLUSIONS: This is the first randomized controlled trial to assess the effect of the policy on overall mortality. VAS had no overall effect, but the effect differed significantly by gender. More trials to ensure an optimal evidence-based vitamin A policy are warranted.

High-dose vitamin A supplementation administered with vaccinations after 6 months of age: sex-differential adverse reactions and morbidity.

BACKGROUND: WHO recommends vitamin A supplementation (VAS) at vaccination contacts after six months of age. The effect of this recommendation on mortality has not been evaluated. METHODS: We tested the effect of VAS at vaccination contacts on mortality in a randomised trial in Guinea-Bissau. In a subgroup within this trial we studied adverse reactions to VAS and whether VAS modified known adverse reactions to live and inactivated vaccines and general morbidity during the first month after supplementation overall and by sex. Children aged 6-17 months were randomised to VAS or placebo at the day of vaccination (day 0). We interviewed the caretaker, assessed the fontanel and measured temperature and local reaction at the injection site at home visits on day 1, 2, 3, 7, 14, 21, and 31. We defined systemic adverse reactions to inactivated and live vaccines as fever on day 1 and 2 and on 4-14 respectively. Clinical symptoms associated with increased intracranial pressure (ICP) on day 1 were considered possible adverse reactions to VAS. RESULTS: In 1673 children VAS had no overall effect on clinical symptoms associated with increased ICP (Relative Risk(RR)=1.07 (95%CI: 0.85-1.35)). However, VAS was associated with such clinical symptoms in boys RR=1.38 (1.00-1.91)) but not in girls (p=0.03 for interaction between VAS and sex). VAS had no effect on fever after inactivated vaccines. VAS had no overall effect on fever after live vaccines (RR=0.86 (0.53-1.39)), but tended to reduce the prevalence of fever in boys (RR=0.58 (0.30-1.14)), but not in girls (RR=1.37 (0.66-2.84)) (p=0.09 for interaction between VAS and sex). VAS was associated with increased local reactions to measles vaccine in both sexes (RR=3.65 (1.20-11.12)). CONCLUSION: Adverse reactions were rare, mild and transient and may not in their own right cause concern. However, VAS caused sex-differential adverse reactions and may have sex-differential effects on adverse reactions to vaccines.

Does the effect of vitamin A supplements depend on vaccination status? An observational study from Guinea-Bissau.

Objective Vitamin A supplementation (VAS) is estimated to reduce all-cause mortality by 24%. Previous studies indicate that the effect of VAS may vary with vaccination status. The authors evaluated the effect of VAS provided in campaigns on child survival overall and by sex and vaccination status at the time of supplementation. Design Observational cohort study. Setting and participants The study was conducted in the urban study area of the Bandim Health Project in Guinea-Bissau. The authors documented participation or non-participation in two national vitamin A campaigns in December 2007 and July 2008 for children between 6 and 35 months of age. Vaccination status was ascertained by inspection of vaccination cards. All children were followed prospectively. Outcome measures Mortality rates for supplemented and non-supplemented children were compared in Cox models providing mortality rate ratios (MRRs). Results The authors obtained information from 93% of 5567 children in 2007 and 90% of 5799 children in 2008. The VAS coverage was 58% in 2007 and 68% in 2008. Mortality in the supplemented group was 1.5% (44 deaths/2873 person-years) and 1.6% (20 deaths/1260 person-years) in the non-supplemented group (adjusted MRR=0.78 (0.46; 1.34)). The effect was similar in boys and girls. Vaccination cards were seen for 86% in 2007 and 84% in 2008. The effect of VAS in children who had measles vaccine as their last vaccine (2814 children, adjusted MRR=0.34 (0.14; 0.85)) differed from the effect in children who had diphtheria-tetanus-pertussis vaccine as their last vaccine (3680 children, adjusted MRR=1.29 (0.52; 3.22), p=0.04 for interaction). Conclusion The effect of VAS differed by most recent vaccination, being beneficial after measles vaccine but not after diphtheria-tetanus-pertussis vaccine.

Risk factors for measles in young infants in an urban African area with high measles vaccination coverage.

BACKGROUND: We examined risk factors for measles infection before measles vaccination at 9 months of age in Guinea-Bissau. METHODS: Among 1524 children enrolled in a trial of early measles vaccination at 4.5 months of age, we assessed the relative risk (RR) of measles before enrollment and the incidence rate ratio between 4.5 and 9 months of age for different groups. RESULTS: The incidence was high, with 4% having measles before 4.5 months and 10% having measles between 4.5 and 9 months of age. The main risk factor was the age of the mother; children of young mothers (age, 15-24 years) had lower antibody titers and higher risk of measles than children of older mothers both before 4.5 months (RR = 1.74 [1.02-2.96]) and between 4.5 and 9 months of age (incidence rate ratio = 1.59 [1.05-2.41]). Having no Bacillus Calmette-Guérin scar was associated with a higher risk of measles before 4.5 months of age (RR = 2.61 [1.54-4.45]). Children who were not breast-fed and had fever or respiratory infection at enrollment had a 2- to 4-fold higher risk of measles between 4.5 and 9 months of age. INTERPRETATION: Young mothers transmit lower titers of antibodies to their children and an increasing proportion of infants become susceptible to measles before the age of measles vaccination.

Non-specific effects of standard measles vaccine at 4.5 and 9 months of age on childhood mortality: randomised controlled trial.

OBJECTIVE: To examine in a randomised trial whether a 25% difference in mortality exists between 4.5 months and 3 years of age for children given two standard doses of Edmonston-Zagreb measles vaccines at 4.5 and 9 months of age compared with those given one dose of measles vaccine at 9 months of age (current policy). DESIGN: Randomised controlled trial. SETTING: The Bandim Health Project, Guinea-Bissau, which maintains a health and demographic surveillance system in an urban area. PARTICIPANTS: 6648 children aged 4.5 months of age who had received three doses of diphtheria-tetanus-pertussis vaccine at least four weeks before enrolment. A large proportion of the children (80%) had previously taken part in randomised trials of neonatal vitamin A supplementation. INTERVENTION: Children were randomised to receive Edmonston-Zagreb measles vaccine at 4.5 and 9 months of age (group A), no vaccine at 4.5 months and Edmonston-Zagreb measles vaccine at 9 months of age (group B), or no vaccine at 4.5 months and Schwarz measles vaccine at 9 months of age (group C). Main outcome measure Mortality rate ratio between 4.5 and 36 months of age for group A compared with groups B and C. Secondary outcomes tested the hypothesis that the beneficial effect was stronger in the 4.5 to 9 months age group, in girls, and in the dry season, but the study was not powered to test whether effects differed significantly between subgroups. RESULTS: In the intention to treat analysis of mortality between 4.5 and 36 months of age the mortality rate ratio of children who received two doses of Edmonston-Zagreb vaccine at 4.5 and 9 months of age compared with those who received a single dose of Edmonston-Zagreb vaccine or Schwarz vaccine at 9 months of age was 0.78 (95% confidence interval 0.59 to 1.05). In the analyses of secondary outcomes, the intention to treat mortality rate ratio was 0.67 (0.38 to 1.19) between 4.5 and 9 months and 0.83 (0.83 to 1.16) between 9 and 36 months of age. The effect on mortality between 4.5 and 36 months of age was significant for girls (intention to treat mortality rate ratio 0.64 (0.42 to 0.98)), although this was not significantly different from the effect in boys (0.95 (0.64 to 1.42)) (interaction test, P=0.18). The effect did not differ between the dry season and the rainy season. As neonatal vitamin A supplementation is not WHO policy, the analyses were done separately for the 3402 children who did not receive neonatal vitamin A. In these children, the two dose Edmonston-Zagreb measles vaccine schedule was associated with a significantly lower mortality between 4.5 and 36 months of age (intention to treat mortality rate ratio 0.59 (0.39 to 0.89)). The effect was again significant for girls but not statistically significant from the effect in boys. When measles cases were censored, the intention to treat mortality rate ratio was 0.65 (0.43 to 0.99). CONCLUSIONS: Although the overall effect did not reach statistical significance, the results may indicate that a two dose schedule with Edmonston-Zagreb measles vaccine given at 4.5 and 9 months of age has beneficial non-specific effects on children's survival, particularly for girls and for children who have not received neonatal vitamin A. This should be tested in future studies in different locations. TRIAL REGISTRATION: Clinical trials NCT00168558.

Sex differences in the effect of vaccines on the risk of hospitalization due to measles in Guinea-bissau.

BACKGROUND: Routine immunizations have non-specific and sex-differential effects on childhood mortality and morbidity in low-income countries; BCG and measles vaccine (MV) may reduce and diphtheria-tetanus-pertussis vaccine (DTP) may increase the mortality of girls relative to boys. SETTING: Urban area in Guinea-Bissau, with a demographic surveillance system and registration of all pediatric hospitalizations. Guinea-Bissau experienced a large outbreak of measles infection in 2003-2004. DESIGN: We used hospital and community data to examine the impact of other vaccines on the risk of hospitalizations for measles infection. Vaccine efficacy (VE) against hospitalization for children aged 6 to 59 months of age was examined. We assessed whether VE depended on vaccination status for other vaccines and whether the pattern differed for boys and girls. MAIN OUTCOME MEASURE: Sex-specific vaccine efficacy against hospitalization for children aged 6 to 59 months of age. RESULTS: The VE depended on sex and the sequence of vaccinations. The VE of MV against hospitalization for measles was better for girls than for boys. Among children who had received MV as the most recent vaccine VE against hospitalization was as high as 96% for girls, but only 81% for boys (P = 0.002). Among children who had received DTP simultaneously with MV or DTP after MV, VE declined for girls (91%) and increased for boys (90%). Compared with having received MV as most recent vaccination, DTP simultaneously with MV or DTP after MV improved the efficacy significantly for boys and the effect was significantly different for boys and girls (P = 0.023). The female-male risk ratio of hospitalization varied significantly, depending on the most recent vaccination (P = 0.014); it was 0.28 (0.11-0.68) for MV alone, but 1.21 (0.82-1.77) for DTP but no MV, and 1.13 (0.58-2.18) for DTP simultaneously with MV or after MV. Among MV-unvaccinated children, BCG-vaccinated girls had a lower risk of measles hospitalization than DTP-vaccinated girls (RR=0.0 (0.0-0.99), exact test).

Protective efficacy of standard Edmonston-Zagreb measles vaccination in infants aged 4.5 months: interim analysis of a randomised clinical trial.

OBJECTIVE: To examine the protective efficacy of measles vaccination in infants in a low income country before 9 months of age. DESIGN: Randomised clinical trial. PARTICIPANTS: 1333 infants aged 4.5 months: 441 in treatment group and 892 in control group. SETTING: Urban area in Guinea-Bissau. INTERVENTION: Measles vaccination using standard titre Edmonston-Zagreb vaccine at 4.5 months of age. MAIN OUTCOME MEASURES: Vaccine efficacy against measles infection, admission to hospital for measles, and measles mortality before standard vaccination at 9 months of age. RESULTS: 28% of the children tested at 4.5 months of age had protective levels of maternal antibodies against measles at enrolment. After early vaccination against measles 92% had measles antibodies at 9 months of age. A measles outbreak offered a unique situation for testing the efficacy of early measles vaccination. During the outbreak, 96 children developed measles; 19% of unvaccinated children had measles before 9 months of age. The monthly incidence of measles among the 441 children enrolled in the treatment arm was 0.7% and among the 892 enrolled in the control arm was 3.1%. Early vaccination with the Edmonston-Zagreb measles vaccine prevented infection; vaccine efficacy for children with serologically confirmed measles and definite clinical measles was 94% (95% confidence interval 77% to 99%), for admissions to hospital for measles was 100% (46% to 100%), and for measles mortality was 100% (-42% to 100%). The number needed to treat to prevent one case of measles between ages 4.5 months and 9 months during the epidemic was 7.2 (6.8 to 9.2). The treatment group tended to have lower overall mortality (mortality rate ratio 0.18, 0.02 to 1.36) although this was not significant. CONCLUSIONS: In low income countries, maternal antibody levels against measles may be low and severe outbreaks of measles can occur in infants before the recommended age of vaccination at 9 months. Outbreaks of measles may be curtailed by measles vaccination using the Edmonston-Zagreb vaccine as early as 4.5 months of age. TRIAL REGISTRATION CLINICAL TRIALS: NCT00168558 [ClinicalTrials.gov].