Effect of high-dose vitamin A supplementation on the immune response to Bacille Calmette-Guerin vaccine

Bandim Health Project, INDEPTH Network, Bissau, Guinea-Bissau.
American Journal of Clinical Nutrition (Impact Factor: 6.77). 11/2007; 86(4):1152-9.
Source: PubMed


Vitamin A supplementation (VAS) at birth has been associated with decreased mortality in Asia. Bacille Calmette-Guérin (BCG) vaccine is given at birth in tuberculosis-endemic countries. Previous studies suggest that VAS may influence the immune response to vaccines.
Our objective was to examine whether VAS influences the immune response to simultaneously administered BCG vaccine.
Within a randomized trial of 50,000 IU vitamin A or placebo given with BCG vaccine at birth in Guinea-Bissau, 2710 infants were examined for BCG scar formation and delayed-type hypersensitivity (DTH) to purified protein derivative of Mycobacterium tuberculosis (PPD) at 2 and 6 mo of age. The ex vivo cytokine response to PPD was measured in 607 infants.
At 2 mo of age, 39% (43% of the boys and 34% of the girls) responded to PPD. The prevalence ratio of a measurable PPD reaction for VAS compared with placebo recipients was 0.90 (95% CI: 0.80, 1.02) for all infants, 0.81 (95% CI: 0.69, 0.95) for boys, and 1.04 (95% CI: 0.86, 1.26) for girls. At 6 mo of age, 42% of the infants responded to PPD. No difference was observed between VAS and placebo recipients. The prevalence of BCG scar was not affected by VAS. The ex vivo interferon-gamma response to PPD was increased by VAS (means ratio: 1.40; 95% CI: 1.03, 1.91).
VAS with BCG vaccination does not appear to interfere with the long-term immune response to BCG. However, VAS temporarily altered the DTH reaction to PPD in boys at 2 mo of age, suggesting sex differences in the immunologic response to VAS given with BCG. This trial was registered at as #NCT00168597.

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    • "A very limited number of immunological studies have been conducted on VAS in human neonates. A RCT conducted in Guinea Bissau found no effect on NNVAS and immune responses to BCG vaccine at 6 months of age [31], however studies nested within this trial, analysed by sex, found that in boys less than 6 months of age, VAS had a beneficial effect on non-rotavirus diarrhoea [32] and was also associated with less measles hospitalisations and deaths [33]. Given such wide ranging immunological effects and the uncertainty about whether NNVAS is beneficial or not, this study set out to investigate the effect of NNVAS in a West African neonatal population. "
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    ABSTRACT: Vitamin A supplementation significantly reduces all-cause mortality when given between 6-59 months of age, but has a null or detrimental effect when given between 1-5 months. Studies of neonatal vitamin A supplementation conducted across Africa and South Asia have produced conflicting findings. These age-pattern variations might result from immunological interactions between vitamin A supplementation and vaccines. Knowledge on the potential immunological sequelae of human neonatal vitamin A supplementation is so scarce that the foremost aim of this study is to seek indicative data on aspects of immunity likely to be affected by neonatal vitamin A supplementation. The objective of this trial is to test whether human neonatal vitamin A supplementation modulates immune function including improved thymic maturation in infancy and improved systemic immune responses to routine immunization.Methods/design: In an area of moderate vitamin A deficiency in a peri-urban area of The Gambia, 200 mother-infant pairs were enrolled in a double-blind randomised controlled trial. Within 48 hours of birth, neonates were randomised with stratification by birth weight and sex to receive either an oral dose of 50,000 IU vitamin A or placebo. Expanded Programme of Immunisation birth vaccinations were administered after supplementation, with subsequent vaccinations administered at 8, 12 and 16 weeks of age. A range of immunological outcomes were examined up to 17 weeks of age, with additional morbidity and anthropometry follow-up carried out throughout the first year of life. The primary endpoint of this trial is the frequency of circulating T regulatory (Treg) cells expressing gut homing receptors in infants at 17 week post-supplementation, with secondary outcomes including thymus maturation and B cell immune responses. Indicative immunological data from this trial (and its Bangladeshi counterpart), will complement the larger randomised controlled trials (conducted in India, Tanzania and Ghana), on the effectiveness and safety of neonatal vitamin A supplementation in improving infant survival. Combined these trials, in addition to the existing trials, will inform policy.Trial registration: NCT01476358.
    Full-text · Article · Apr 2014 · BMC Pediatrics
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    • "When the number of NDs is rather small, one approach of dealing with NDs is simply dropping NDs and apply linear regression to the remaining data. A second commonly used approach is to substitute NDs with a certain value smaller than the DL (0, DL/2 or DL) and to use linear regression [3,4]. The validity of these approaches will depend on the number and the unknown range of NDs. "
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    ABSTRACT: The statistical analysis of immunological data may be complicated because precise quantitative levels cannot always be determined. Values below a given detection limit may not be observed (nondetects), and data with nondetects are called left-censored. Since nondetects cannot be considered as missing at random, a statistician faced with data containing these nondetects must decide how to combine nondetects with detects. Till now, the common practice is to impute each nondetect with a single value such as a half of the detection limit, and to conduct ordinary regression analysis. The first aim of this paper is to give an overview of methods to analyze, and to provide new methods handling censored data other than an (ordinary) linear regression. The second aim is to compare these methods by simulation studies based on real data. We compared six new and existing methods: deletion of nondetects, single substitution, extrapolation by regression on order statistics, multiple imputation using maximum likelihood estimation, tobit regression, and logistic regression. The deletion and extrapolation by regression on order statistics methods gave biased parameter estimates. The single substitution method underestimated variances, and logistic regression suffered loss of power. Based on simulation studies, we found that tobit regression performed well when the proportion of nondetects was less than 30%, and that taken together the multiple imputation method performed best. Based on simulation studies, the newly developed multiple imputation method performed consistently well under different scenarios of various proportion of nondetects, sample sizes and even in the presence of heteroscedastic errors.
    Full-text · Article · Nov 2008 · BMC Immunology
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    ABSTRACT: To investigate the effect of high dose vitamin A supplementation given with BCG vaccine at birth in an African setting with high infant mortality. Randomised placebo controlled trial. Setting Bandim Health Project's demographic surveillance system in Guinea-Bissau, covering approximately 90,000 inhabitants. Participants 4345 infants due to receive BCG. Infants were randomised to 50,000 IU vitamin A or placebo and followed until age 12 months. Mortality rate ratios. 174 children died during follow-up (mortality=47/1000 person-years). Vitamin A supplementation was not significantly associated with mortality; the mortality rate ratio was 1.07 (95% confidence interval 0.79 to 1.44). The effect was 1.00 (0.65 to 1.56) during the first four months and 1.13 (0.75 to 1.68) from 4 to 12 months of age. The mortality rate ratio in boys was 0.84 (0.55 to 1.27) compared with 1.39 (0.90 to 2.14) in girls (P for interaction=0.10). An explorative analysis revealed a strong interaction between vitamin A and season of administration. Vitamin A supplementation given with BCG vaccine at birth had no significant benefit in this African setting. Although little doubt exists that vitamin A supplementation reduces mortality in older children, a global recommendation of supplementation for all newborn infants may not contribute to better survival. Clinical trials NCT00168597.
    Full-text · Article · Jul 2008 · BMJ (online)
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