Vitamin A supplements and mortality related to measles: a randomised clinical trial

Vitamin a deficiency and clinical disease: an historical overview

Vitamin A deficiency has a plethora of clinical manifestations, ranging from xerophthalmia (practically pathognomonic) to disturbances in growth and susceptibility to severe infection (far more protean). Like other classical vitamin deficiency states (scurvy, rickets), some of the signs and symptoms of xerophthalmia were recognized long ago. Reports related to vitamin A and/or manifestations of deficiency might conveniently be divided into "ancient" accounts; eighteenth to nineteenth century clinical descriptions (and their purported etiologic associations); early twentieth century laboratory animal experiments and clinical and epidemiologic observations that identified the existence of this unique nutrient and manifestations of its deficiency; and, most recently, a flowering of carefully conducted clinical studies and field-based randomized trials that documented the full extent and impact of deficiency among the poor of low- and middle-income countries, which in turn changed global health policy.

Undernutrition, infection and immune function

Undernutrition and infection are the major causes of morbidity and mortality in the developing world. These two problems are interrelated. Undernutrition compromises barrier function, allowing easier access by pathogens, and compromises immune function, decreasing the ability of the host to eliminate pathogens once they enter the body. Thus, malnutrition predisposes to infections. Infections can alter nutritional status mediated by changes in dietary intake, absorption and nutrient requirements and losses of endogenous nutrients. Thus, the presence of infections can contribute to the malnourished state. The global burden of malnutrition and infectious disease is immense, especially amongst children. Childhood infections impair growth and development. There is a role for breast-feeding in protection against infections. Key nutrients required for an efficient immune response include vitamin A, Fe, Zn and Cu. There is some evidence that provision of the first three of these nutrients does improve immune function in undernourished children and can reduce the morbidity and mortality of some infectious diseases including measles, diarrhoeal disease and upper and lower respiratory tract infections. Not all studies, however, show benefit of single nutrient supplementation and this might be because the subjects studied have multiple nutrient deficiencies. The situation regarding Fe supplementation is particularly complex. In addition to immunization programmes and improvement of nutrient status, there are important roles for maternal education, improved hygiene and sanitation and increased supply of quality water in the eradication of infectious diseases.

An overview of interactions between micronutrients and of micronutrients with drugs, genes and immune mechanisms

The objective of the present review is to examine critically the consequences of interactions that micronutrients undergo with nutrients and non-nutrients (mainly prescribed medicines) in diets and lifestyle factors (smoking, tea and alcohol consumption). In addition, the review describes recent work on interactions between nutrients and genes, the influence of gene polymorphisms on micronutrients, the impact of immune responses on micronutrients and specific interactions of antioxidant micronutrients in disease processes to minimise potential pro-oxidant damage.

Newborn vitamin A dosing reduces the case fatality but not incidence of common childhood morbidities in South India

Vitamin A supplementation reduces mortality in young children in areas of endemic vitamin A deficiency. However, it has no impact on the incidence of common morbidities. This discrepancy has been explained by an impact on case fatality, although with the exception of hospitalized measles cases, there is little direct evidence to support this hypothesis. We assessed the impact of newborn dosing with vitamin A on the incidence and case fatality of common childhood morbidities in early infancy in a community-based, randomized trial in South India. Morbidity for each day in the previous 2 wk was assessed for the first 6 mo of life. A total of 11,619 live-born infants were enrolled and randomized to receive either 48,000 IU (50.4 micromol retinol) of oral vitamin A or placebo following delivery. There was no difference between treatment groups in the incidence of acute or chronic diarrhea, dysentery, or fever but a small increased incidence of acute respiratory illness (ARI). Case fatality for diarrhea and fever were significantly reduced in the vitamin A group compared with placebo (relative case fatality [95% CI] of 0.50 [0.27, 0.90] and 0.60 [0.40, 0.88], respectively). There was a trend in reduction of case fatality for various definitions of ARI, but the evidence for this effect was modest. Survival analysis among those with morbid episodes confirmed the case fatality analysis. This trial demonstrated that the reduction in overall mortality due to newborn vitamin A dosing was driven primarily by a reduction in case fatality among infants.

Effect of daily low dose of vitamin A compared with single high dose on morbidity and mortality of hospitalized mainly malnourished children in senegal: a randomized controlled clinical trial

BACKGROUND

In vitamin A-deficient populations, children hospitalized with infections and/or malnutrition are at particular risk of developing severe vitamin A (VA) deficiency. High-dose VA supplements are recommended as part of the treatment but results on its effect on recovery from morbidity and on prevention from nosocomial morbidity are conflicting.

OBJECTIVE

We aimed to assess the effect of a single high dose and daily low dose of VA on hospitalized malnourished children's morbidity.

DESIGN

We carried out a double-blind, randomized trial in 604 and 610 Senegalese hospitalized children. The first mentioned batch received a high-dose VA supplement (200,000 IU) on admission, the second a daily low-dose VA supplement (5000 IU per day) during hospitalization. Children were followed up until discharged. Data on all-cause morbidity were collected daily.

RESULTS

Survival analysis showed that the incidence of respiratory disease was significantly lower in the low-dose group than in the high-dose group, hazard ratios (HR): 0.26, 95% CI: 0.07-0.92. The duration of respiratory infection was also significantly lower in the low-dose group than in the high-dose group (HR of cure: 1.41, 95% CI: 1.05-1.89). Duration and incidence of diarrhoea were not significantly different between treatment groups. In children with oedema on admission, mortality was significantly lower in the low-dose group (Adjusted odds ratio: 0.21; 95% CI: 0.05-0.99).

CONCLUSIONS

Daily low dose of VA compared with single high dose significantly reduced duration and incidence of respiratory infection but not of diarrhoea in hospitalized children.

Has the 2005 measles mortality reduction goal been achieved? A natural history modelling study

BACKGROUND

In 2002, the UN General Assembly Special Session on Children adopted a goal to reduce deaths owing to measles by half by the end of 2005, compared with 1999 estimates. We describe efforts and progress made towards this goal.

METHODS

We assessed trends in immunisation against measles on the basis of national implementation of the WHO/UNICEF comprehensive strategy for measles mortality reduction, and the provision of a second opportunity for measles immunisation. We used a natural history model to evaluate trends in mortality due to measles.

RESULTS

Between 1999 and 2005, according to our model mortality owing to measles was reduced by 60%, from an estimated 873,000 deaths (uncertainty bounds 634,000-1,140,000) in 1999 to 345,000 deaths (247,000-458,000) in 2005. The largest percentage reduction in estimated measles mortality during this period was in the western Pacific region (81%), followed by Africa (75%) and the eastern Mediterranean region (62%). Africa achieved the largest total reduction, contributing 72% of the global reduction in measles mortality. Nearly 7.5 million deaths from measles were prevented through immunisation between 1999 and 2005, with supplemental immunisation activities and improved routine immunisation accounting for 2.3 million of these prevented deaths.

INTERPRETATION

The achievement of the 2005 global measles mortality reduction goal is evidence of what can be accomplished for child survival in countries with high childhood mortality when safe, cost-effective, and affordable interventions are backed by country-level political commitment and an effective international partnership.

Sierra Leone – investing in nutrition to reduce poverty: a call for action

Background:

Malnutrition rates in Sierra Leone are among the highest in the world. However, policy-makers do not always recognise the fight against malnutrition as a policy priority to ensure the healthy human capital needed to fight poverty and achieve sustained positive economic growth.

Objective:

The analysis presented here was conducted by an intersectoral and inter-agency group of Sierra Leonean senior policy advisors to quantify some of the potential human and economic benefits of improved policies and programmes to reduce malnutrition.

Findings:

The analysis revealed that 46% of child deaths in Sierra Leone are attributable to malnutrition, the single greatest cause of child mortality in the country. In the absence of adequate policy and programme action, malnutrition will be the underlying cause of an estimated 74000 child deaths over the next five years. The analysis also revealed that if current levels of iodine deficiency remain unchanged over the next five years, 252000 children could be born with varying degrees of mental retardation as a result of intrauterine iodine deficiency. Finally, the analysis showed that, in the absence of adequate policy and programme action to reduce the unacceptable rates of anaemia in women, the monetary value of agricultural productivity losses associated with anaemia in the female labour force over the next five years will exceed $94.5 million.

Conclusion:

Sustained investment in nutrition in Sierra Leone could bring about enormous human and economic benefits to develop the social sector, revitalise the economy, and attain the poverty reduction goals that Sierra Leone has set forth.

Vitamin A deficiency and child survival in sub-Saharan Africa: a reappraisal of challenges and opportunities

BACKGROUND

Children with vitamin A deficiency have higher risk of morbidity and mortality than vitamin A-sufficient children. Estimates on the potential child survival benefits of vitamin A deficiency control are needed for policy and program advocacy.

OBJECTIVE

To determine the current prevalence of children at risk for vitamin A deficiency in sub-Saharan Africa in order to estimate the potential child-survival benefits of effective and sustained policies and programs for the control of vitamin A deficiency in this region.

METHODS

Estimates of the prevalence of vitamin A deficiency generated in 1998, data from 11 nationally representative vitamin A deficiency surveys conducted in sub-Saharan Africa between 1997 and 2003, and the measured effects of vitamin A deficiency on child mortality were combined to estimate the prevalence of children at risk for vitamin A deficiency in sub-Saharan Africa and the potential child-survival benefits of effective and sustained policies and programs for the control of vitamin A deficiency in this region.

RESULTS

Our analysis shows that in the absence of effective and sustained policies and programs for the control of vitamin A deficiency, an estimated 42.4% of children 0 to 59 months of age in sub-Saharan Africa (43.2 million children) are at risk for vitamin A deficiency. Such effective and sustained policy and program action for the control of vitamin A deficiency can bring about a potential 25% reduction in mortality in children 0 to 59 months with respect to 1995 mortality levels (i.e., before the onset of large-scale vitamin A supplementation programs in sub-Saharan Africa).

CONCLUSIONS

Effective and sustained control of vitamin A deficiency has the potential to be among the most cost-effective and high-impact child-survival interventions in sub-Saharan Africa. A stronger political commitment and a more appropriate level of investment in the effective control of vitamin A deficiency could make a large contribution toward the attainment of the Millennium Development Goal for the reduction of child mortality rates by two-thirds between 1990 and 2015. Among the many challenges that Africa will need to face in the coming years, vitamin A deficiency is one that can be overcome. The need is urgent, and the solutions are known, effective, and affordable.

Effects of moderate doses of vitamin A as an adjunct to the treatment of pneumonia in underweight and normal-weight children: a randomized, double-blind, placebo-controlled trial

BACKGROUND

Randomized controlled trials have shown inconsistent responses of childhood pneumonia to the use of vitamin A as an adjunct to the standard treatment of pneumonia.

OBJECTIVE

We evaluated the effect of a moderate dose of vitamin A as an adjunct to standard antimicrobial treatment on the duration of respiratory signs in children with pneumonia.

DESIGN

Children, aged 2-59 mo, with pneumonia and weight-for-age <50th percentile who had been admitted to the Baca Ortíz Children's Hospital in Quito, Ecuador, were randomly assigned to receive 50,000 IU (aged 2-12 mo) or 100,000 IU (aged >12-59 mo) vitamin A or a placebo.

RESULTS

Of the 287 children enrolled, 145 received vitamin A and 142 received placebo. No overall differences were observed between the 2 groups in the duration of signs of pneumonia. Multiple linear regression showed a significant interaction between basal serum retinol concentration and vitamin A group for the time (in h) to remission of respiratory signs (beta = -3.57, SE = 1.09, P = 0.001). Duration of clinical signs was less in children with basal serum retinol concentrations >200 microg/L who received vitamin A supplements than in children with similar concentrations who received placebo (69.9 +/- 49.9 h compared with 131.3 +/- 143.9 h; P = 0.049).

CONCLUSIONS

Overall, we found no effect of a moderate dose of vitamin A supplementation on the duration of uncomplicated pneumonia in underweight or normal-weight children aged <5 y. However, a beneficial effect was seen in children with high basal serum retinol concentrations.

Vitamin A for treating measles in children

BACKGROUND

Measles is a major cause of childhood morbidity and mortality. Vitamin A deficiency is a recognized risk factor for severe measles infections. The World Health Organization (WHO) recommends administration of an oral dose of vitamin A (200,000 international units (IU), or 100,000 IU in infants) each day for two days to children with measles when they live in areas where vitamin A deficiency may be present.

OBJECTIVES

To determine whether vitamin A therapy, commenced after measles has been diagnosed, is beneficial in preventing mortality, pneumonia and other secondary complications in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to March 2005), EMBASE (1980 to December 2004) and looked for unpublished studies.

SELECTION CRITERIA

Only randomized controlled trials in which children with measles were given vitamin A or placebo along with standard treatment were considered.

DATA COLLECTION AND ANALYSIS

Studies were assessed independently by two authors. The analysis of dichotomous outcomes was done using the StatXact software and results expressed as relative risk (RR) with 95% confidence interval (CI). Subgroup analyses were carried out for dose, formulation, age, hospitalization and pneumonia-specific mortality. Weighted mean differences (WMD) with 95% CI were calculated for continuous outcomes.

MAIN RESULTS

There was no significant reduction in the risk of mortality in the vitamin A group when all the studies were pooled using the random-effects model (RR 0.70; 95% CI 0.42 to 1.15). Using two doses of vitamin A (200,000 IU) on consecutive days was associated with a reduction in the risk of mortality in children under the age of two years (RR 0.18; 95% CI 0.03 to 0.61) and a reduction in the risk of pneumonia-specific mortality (RR 0.33; 95% CI 0.08 to 0.92). There was no evidence that vitamin A in a single dose was associated with a reduced risk of mortality among children with measles. There was a reduction in the incidence of croup (RR 0.53; 95% CI 0.29 to 0.89) but no significant reduction in the incidence of pneumonia (RR 0.92; 95% CI 0.69 to 1.22) or diarrhoea (RR 0.80; 95% CI 0.27 to 2.34) with two doses.

AUTHORS' CONCLUSIONS

Although we found no overall significant reduction in mortality with vitamin A therapy for children with measles there was evidence that two doses were associated with a reduced risk of mortality and pneumonia-specific mortality in children under the age of two years. There were no trials that directly compared a single dose with two doses.

Effects of vitamin a supplementation on immune responses and correlation with clinical outcomes

Vitamin A supplementation to preschool children is known to decrease the risks of mortality and morbidity from some forms of diarrhea, measles, human immunodeficiency virus (HIV) infection, and malaria. These effects are likely to be the result of the actions of vitamin A on immunity. Some of the immunomodulatory mechanisms of vitamin A have been described in clinical trials and can be correlated with clinical outcomes of supplementation. The effects on morbidity from measles are related to enhanced antibody production and lymphocyte proliferation. Benefits for severe diarrhea could be attributable to the functions of vitamin A in sustaining the integrity of mucosal epithelia in the gut, whereas positive effects among HIV-infected children could also be related to increased T-cell lymphopoiesis. There is no conclusive evidence for a direct effect of vitamin A supplementation on cytokine production or lymphocyte activation. Under certain circumstances, vitamin A supplementation to infants has the potential to improve the antibody response to some vaccines, including tetanus and diphtheria toxoids and measles. There is limited research on the effects of vitamin A supplementation to adults and the elderly on their immune function; currently available data provide no consistent evidence for beneficial effects. Additional studies with these age groups are needed.

Maintaining High Vitamin A Supplementation Coverage in Children: Lessons from Niger

In 1997, the reduction of child mortality became a policy priority for the Government of Niger because Niger's child mortality rate was the highest in the world. The Ministry of Public Health, Helen Keller International (HKI), and UNICEF spearheaded a coalition-building process linking vitamin A deficiency (VAD) control to national child survival goals. An evidence-based advocacy strategy was developed around the child survival benefits of adequate and sustained VAD control with one unambiguous message: “VAD control can avert over 25,000 child deaths per year.” As a result, in 1997 Niger became one of the first countries in Africa to effectively integrate vitamin A supplementation into National Immunization Days (NIDs) for polio eradication. The challenge was then to provide children with a second annual dose of vitamin A. This led in 1999 to the first ever National Micronutrient Days (NMDs) in Africa. NMDs are mobilization campaigns in which caregivers are actively encouraged to take their children for the delivery of vitamin A supplements. Since 1999, the combination of NIDs and NMDs has ensured that over 80% of children 6 to 59 months of age receive two vitamin A doses annually. The success of NIDs/NMDs has relied on five pillars: leadership and ownership by the Ministry of Public Health; district-level planning and implementation; effective training and flexible delivery mechanisms; effective social information, communication, and mobilization; and responsiveness and flexibility of Ministry of Public Health and development partners. This successful approach has been widely disseminated, notably through the West African Nutrition Focal Points Network.

Efficacy of interventions for bronchiolitis in critically ill infants: a systematic review and meta-analysis

BACKGROUND

Viral bronchiolitis is the leading cause of respiratory failure among infants in the United States. Currently, the mainstay of treatment is supportive care. The effectiveness of treatments used for mechanically ventilated infants with bronchiolitis is unclear.

OBJECTIVE

To evaluate the strength of the evidence supporting the use of currently available treatments for critically ill infants with bronchiolitis.

DATA SOURCE

We searched PubMed, citations of relevant articles, personal files, and conference proceedings, and we contacted experts in the field.

STUDY SELECTION

Randomized, controlled trials evaluating any therapy for bronchiolitis that included children in an intensive care unit.

DATA EXTRACTION

Two reviewers independently extracted data and assessed methodologic quality.

DATA SYNTHESIS

A total of 2,319 citations were screened, and 16 randomized, controlled trials were included. There were three trials of surfactant, three of ribavirin, three of immune globulin, three of systemic corticosteroids, and one each of vitamin A, interferon, erythropoietin, and heliox. A meta-analysis of the three surfactant studies showed a strong trend toward a decrease in duration of mechanical ventilation of 2.58 days (95% confidence interval, -5.34 to 0.18 days; p =.07) and a significant decrease of 3.3 intensive care unit days (95% confidence interval, -6.38 to -0.23 days; p =.04). A meta-analysis of the three systemic corticosteroid studies showed no overall effect on duration of mechanical ventilation when all three trials were combined (-0.62 day; 95% confidence interval, -2.78 to 1.53 days; p =.57). We identified one published meta-analysis of three ribavirin studies showing a significant decrease in ventilator days with ribavirin (-1.2 days; 95% confidence interval, -0.2 to -3.4 days; p =.2).

CONCLUSIONS

Currently, there are no clearly effective interventions available to improve the outcome of critically ill infants with bronchiolitis. Surfactant seems to be a promising intervention, and corticosteroids or ribavirin may also be beneficial.

The clinical significance of measles: a review

Forty years after effective vaccines were licensed, measles continues to cause death and severe disease in children worldwide. Complications from measles can occur in almost every organ system. Pneumonia, croup, and encephalitis are common causes of death; encephalitis is the most common cause of long-term sequelae. Measles remains a common cause of blindness in developing countries. Complication rates are higher in those <5 and >20 years old, although croup and otitis media are more common in those <2 years old and encephalitis in older children and adults. Complication rates are increased by immune deficiency disorders, malnutrition, vitamin A deficiency, intense exposures to measles, and lack of previous measles vaccination. Case-fatality rates have decreased with improvements in socioeconomic status in many countries but remain high in developing countries.

Measles blindness

Measles remains a major problem in developing countries, where it affects an estimated 30 million children a year and causes up to one million deaths annually. Measles blindness is the single leading cause of blindness among children in low income countries, accounting for an estimated 15,000 to 60,000 cases of blindness per year. There is a close synergism between measles and vitamin A deficiency that can result in xerophthalmia, with corneal ulceration, keratomalacia, and subsequent corneal scarring or phthisis bulbi. High-dose oral vitamin A supplementation is recommended for all children with measles in developing countries. Higher measles immunization coverage to interrupt measles transmission and interventions aimed at improving vitamin A nutriture of children are the main strategies to prevent measles blindness.

Randomized, double-blind, placebo-controlled clinical trial of the efficacy of treatment with zinc or vitamin A in infants and young children with severe acute lower respiratory infection

BACKGROUND

Acute lower respiratory infection (ALRI) is a leading cause of childhood death. Zinc supplementation prevents ALRI. Vitamin A supplementation reduces childhood mortality, but its benefit concerning ALRI-specific mortality is unproven.

OBJECTIVE

The objective was to evaluate the effect of zinc and vitamin A on the clinical recovery of children with severe ALRI.

DESIGN

In a controlled trial with a factorial design, 153 children aged 2-24 mo who were hospitalized with severe ALRI were randomly assigned to receive 10 mg zinc as acetate (twice daily for 5 d) plus vitamin A placebo, 10 000 micro g retinol equivalents vitamin A (twice daily for 4 d) plus zinc placebo, zinc plus vitamin A, or zinc and vitamin A placebos. The main outcome variable was the time for resolution of very ill status; other outcomes were resolution of fever, tachypnea, and feeding difficulty.

RESULTS

Recovery rates from very ill status and from fever in zinc-treated boys were 2.6 times (P = 0.004) and 3 times (P = 0.003) those in non-zinc-treated children; feeding difficulty and tachypnea were not significantly different between groups after an adjusted analysis. Recovery rates were not significantly different between groups on the basis of vitamin A treatment. At discharge, serum zinc was 6.06 micro mol/L higher (P = 0.001) in the zinc-treated children, and serum retinol was 0.387 micro mol/L higher (P = 0.001) in the vitamin A-treated children.

CONCLUSION

Zinc treatment significantly reduces duration of fever and very ill status in boys, but not in girls, with severe ALRI. Vitamin A treatment of children with severe ALRI had no significant beneficial effect.

Does vitamin A prevent high-dose-methotrexate-induced D-xylose malabsorption in children with cancer?

PURPOSE

Our aim was to explore whether vitamin A has protective effect on high-dose-methotrexate (HDMTX)-induced intestinal D-xylose malabsorption in children with leukemia and lymphoma.

PATIENTS AND METHODS

We performed a prospective randomized un-blinded study of vitamin A in 35 children with leukemia and lymphoma who were planned to receive HDMTX 3 g/m(2) and 5 g/m(2), respectively. Twenty-two patients (group 1) received a single dose of 180,000 IU a day before HDMTX was given, and 13 (group 2) received only HDMTX. The vitamin A group received the vitamin only once. Oral D-xylose absorption tests before and 7 days after HDMTX were carried out to evaluate intestinal absorption. Retinol-binding protein (RBP) levels prior to therapy were also measured for vitamin A status.

RESULTS

Although we observed no difference of HDMTX-induced toxicity, including hematological, dermatological, systemic, and other toxicities, between groups, the D-xylose absorption test was significantly better in-group 1 ( p=0.030). Absorption was decreased in five of 22 patients (23%) who received vitamin A comparing to eight of 13 (62%) who received only HDMTX ( p=0.033). RBP levels were lower than normal in 13 of 22 patients in-group 1 and nine of 13 in group 2. In patients whose RBP levels were lower than normal, HDMTX-induced toxicity was lower in the group 1 than group 2 but not statistically significant. No sign of vitamin A toxicity was observed throughout the study.

CONCLUSION

The administration of vitamin A before HDMTX may protect against drug-induced D-xylose malabsorption in children with cancer. Further studies are apparently needed to clarify the full benefits of vitamin A in preventing HDMTX-induced mucosal damage.

Vitamin A and infancy. Biochemical, functional, and clinical aspects

Vitamin A is a very intriguing natural compound. The molecule not only has a complex array of physiological functions, but also represents the precursor of promising and powerful new pharmacological agents. Although several aspects of human retinol metabolism, including absorption and tissue delivery, have been clarified, the type and amounts of vitamin A derivatives that are intracellularly produced remain quite elusive. In addition, their precise function and targets still need to be identified. Retinoic acids, undoubtedly, play a major role in explaining activities of retinol, but, recently, a large number of physiological functions have been attributed to different retinoids and to vitamin A itself. One of the primary roles this vitamin plays is in embryogenesis. Almost all steps in organogenesis are controlled by retinoic acids, thus suggesting that retinol is necessary for proper development of embryonic tissues. These considerations point to the dramatic importance of a sufficient intake of vitamin A and explain the consequences if intake of retinol is deficient. However, hypervitaminosis A also has a number of remarkable negative consequences, which, in same cases, could be fatal. Thus, the use of large doses of retinol in the treatment of some human diseases and the use of megavitamin therapy for certain chronic disorders as well as the growing tendency toward vitamin faddism should alert physicians to the possibility of vitamin overdose.

Vitamin A supplementation and childhood morbidity from diarrhea and respiratory infections: a meta-analysis

OBJECTIVES

To perform an updated meta-analysis of the effect of vitamin A supplementation on childhood morbidity from respiratory tract infections and diarrhea. Study design A comprehensive search of the 1966 to 2000 MEDLINE database and review of the reference lists of relevant articles identified 9 randomized controlled trials dealing with morbidity from respiratory infections and diarrhea in children 6 months to 7 years of age and provided "intention-to-treat" data.

RESULTS

The combined results indicated that vitamin A supplementation has no consistent overall protective effect on the incidence of diarrhea (relative risk, 1.00; 95% CI, 0.94-1.07) and that it slightly increases the incidence of respiratory tract infections (relative risk, 1.08; 95% CI, 1.05-1.11).

CONCLUSIONS

High-dose vitamin A supplements are not recommended on a routine basis for all preschool children and should be offered only to individuals or populations with vitamin A deficiency.

Measles: not just another viral exanthem

Measles is the most frequent cause of vaccine-preventable childhood deaths. Infants younger than the recommended age for vaccination are susceptible to the disease, and in developing countries they have a high risk of complications and mortality. Vaccine coverage in excess of 95% interrupts endemic transmission of measles in many countries, but achievement of such coverage almost always requires coordinated supplementary mass vaccination campaigns. There are substantial health gains if countries improve measles vaccine coverage, irrespective of whether or not high coverage is achieved; these gains include much lower measles complication and case fatality rates, long-term interepidemic duration, and possibly non-specific improvements in survival of children. Investigation into the cost-effectiveness of different strategies for measles control, including mass campaigns, two-dose schedules, and young-infant doses, would help countries to formulate control policies appropriate to their setting. Pneumonia is the most common fatal complication associated with measles, and at least 50% of measles-related pneumonias are due to bacterial superinfection. WHO has developed standard case management programmes for measles, but there are several unresolved clinical issues, including optimum indications for antibiotic treatment, the importance of intravenous immunoglobulin, the role of viral coinfection, and the risk of tuberculosis after measles. The priority in worldwide efforts to control measles is to lend support to poor countries, helping them to increase vaccine coverage and sustain improvements to vaccination infrastructure, and to address technical issues with respect to optimum vaccination schedules. Measles represents a specific challenge, whereby partnerships between high-income and developing nations would reduce child mortality in developing countries; such partnerships are not without incentive for high-income countries, since without them imported measles cannot be prevented.

The effect of high single dose parenteral vitamin A in addition to antibiotic therapy on healing of maxillary sinusitis in experimental acute sinusitis

OBJECTIVE

The aim of this study is to investigate the therapeutic role of vitamin A in addition to standard antibiotic treatment on healing of experimental acute maxillary sinusitis.

MATERIAL AND METHODS

Experimental maxillary sinusitis in rabbits was induced by blocking the left noses and direct inoculation of Staphylococcus aureus into the left maxillary sinuse cavities. Right maxillary sinuses were exposed to serum physiologic as the control group. Animals were divided into two groups. Forty-eight hours after the inoculation, Group A received only parenteral ampicilline-sulbactam (50 mg/kg), Group B were treated with same antibiotic regimen and parenteral a dose of 100.000 IU vitamin A in palmitate form. Animals were killed at 10th day and mucosas of each sinuses were examined histopathologically. Inflammation and sinus epithelium integrity were assessed. Groups were compared with using Mann-Whitney U test.

RESULTS

All of the infected sinuses displayed various degrees of inflammation but there was no statistically significant difference between the study and control groups. Although epithelium integrity was slightly better in Group B but the difference was not meaningful.

CONCLUSION

The adjuctive therapeutic role of vitamin A in acute sinusitis was found doubtful but this topic is worth to investigate more comprehensively.

Abnormal vitamin A cytology and mortality in infants aged 9 months and less with measles

We investigated the relationship between abnormal vitamin A cytology and mortality in infants less than 9 months of age with measles. In a 12-month period, 116 children of this age with measles consecutively admitted to Queen Elizabeth Central Hospital (QECH) in Blantyre, Malawi were enrolled in the study. All guardians of patients were interviewed and clinical information and consent were obtained in a standardised fashion. Conjunctival impression cytology (CIC) was attempted on all and collected from 93 (80%) children. The overall mortality was 16%. The proportional hazards model revealed that the presence of pneumonia on admission (hazard ratio 9.58, p = 0.0002) and an abnormal vitamin A CIC on admission (hazard ratio 6.40, p = 0.003) were independently associated with mortality. Our findings suggest a relationship between abnormal vitamin A CIC and fatality in infants under 9 months of age.

Recommendations for vitamin A supplementation

In all populations where vitamin A deficiency is an important public health problem, prophylactic vitamin A supplements should be given to all infants and young children (0-59 mo), pregnant women and postpartum women within 6 wk after delivery. The efficacy of vitamin A supplementation of young children is one of the best-proven, safest and most cost-effective interventions in international public health. The International Vitamin A Consultative Group (IVACG) also recommends that three 50,000-international unit (IU) doses of vitamin A should be given at the same time as infant vaccines during the first 6 mo of life. Recent kinetic studies have indicated that this regimen will be safe and is necessary to maintain the infant's vitamin A stores, even when the mother is also given 400,000 IU within the first 6 wk after delivery. IVACG will make a decision on whether to recommend prophylactic supplementation of all women of childbearing age when the results of two large trials in Ghana and Bangladesh are available. Active corneal xerophthalmia is always a medical emergency that should be treated with immediate high-dose vitamin A. High-dose vitamin A treatment is also recommended for infants and young children with xerophthalmia, severe malnutrition or measles. Low-dose vitamin A treatment is recommended for women with night blindness and/or Bitot's spots. Given the evidence of the cost-effectiveness of vitamin A supplementation, it is essential that effective vitamin A supplementation programs are made universally available to all populations where vitamin A deficiency is an important public health problem.

Why do children become vitamin A deficient?

Vitamin A deficiency is very prevalent and contributes substantially to morbidity and mortality among young children in developing countries. We identify and quantify three causes of vitamin A deficiency in young children based on data available in the literature: maternal vitamin A deficiency resulting in low concentrations of vitamin A in breast milk, inadequate dietary intake of vitamin A during and after weaning and prevalent illness. We developed a set of recursive equations to estimate the amount of vitamin A in the liver as a function of age over the first 2 y of life. To apply the equations, we selected a best estimate value for each input parameter as the most representative of a typical child in a developing country. Because of the great variability that exists for each variable, we also carried out sensitivity analyses, substituting more extreme values for input parameters. We then estimated stores, assuming a child in a developing country also receives the newly revised vitamin A supplementation regimen recommended by the World Health Organization. Without supplementation, a typical child in a developing country is not able to attain and maintain "minimally adequate" liver vitamin A stores. To overcome this deficit by eating fruits and vegetables alone, the child would need to increase portion sizes about 10-fold. If the child receives the new supplementation regimen, his or her liver stores will still be far short of the average American child (i.e., exceedingly far from toxic levels). However, our estimates indicate that the new supplementation regimen will permit a typical child in a developing country setting to attain minimally adequate vitamin A stores during the first 2 y of life.

Immune responses to measles and measles vaccine: challenges for measles control

Most strategies for reducing global measles morbidity and mortality and eliminating measles are based on the ability to enhance immune responses to measles virus. Challenges to measles elimination and eradication are based in part on the need to sustain high levels of population immunity to interrupt transmission of measles virus. We review aspects of the immunology of measles and measles vaccination with the aim of demonstrating how knowledge of the immune responses is essential to furthering the goals of reducing measles morbidity and mortality and the elimination of measles. Better understanding of the mechanisms of immune suppression after measles, the potential for alternative vaccination strategies to induce immunity in young infants, and the immunologic basis of atypical measles, increased mortality after high-titer measles vaccine, and waning immunity will lead to improved strategies for measles control and elimination.

Suplementação com vitamina A: impacto na morbidade e efeitos adversos

Este artigo apresenta uma síntese de dois estudos previamente publicados e que avaliaram diferentes aspectos dos efeitos da suplementação com mega-doses (100.000 ou 200.000 UI) de vitamina A em crianças pré-escolares. O primeiro é um ensaio comunitário, aleatório, duplo cego e placebo controlado, que demonstrou o efeito positivo da suplementação na redução da severidade dos episódios de diarréia. O segundo investigou os potenciais efeitos adversos da suplementação com mega-doses de vitamina A, oferecida conjuntamente com a vacinação em massa, utilizando um desenho de intervenção controlado e não randomizado. Seus resultados indicaram que a suplementação associada com as vacinas rotineiramente utilizadas na infância não elevou as taxas de efeitos adversos (diarréia, febre e vômito). São ainda discutidas as implicações dos resultados destes estudos, que contribuíram não somente para o avanço do conhecimento científico do campo em questão, como também têm fornecido evidências para justificar a implementação de políticas e ações específicas no campo da saúde e da nutrição, que por sua vez têm contribuído para gerar condições mais auspiciosas de sobrevivência na infância. Discute-se também a pertinência e a utilidade de desenhos de estudo com diferentes níveis de rigor metodológico na avaliação de intervenção em saúde.

Measles in bone marrow transplant recipients during an outbreak in São Paulo, Brazil

In 1997, a measles outbreak was identified in São Paulo. Between February and December, 20 185 cases were confirmed. From April to July 1997, a seroepidemiologic survey was conducted to identify the recipients of bone marrow (BM) transplants who were susceptible to measles and the occurrence of measles in this population. A total of 156 patients were screened by enzyme immunoassay (EIA). Patients with IgG titers more than 100 mIU/mL were considered immune. Measles reimmunization records were also reviewed. Thirty-two vaccinated patients underwent serologic evaluation. Six of 22 patients (27.3%) within 3 years after vaccination lost measles immunity, in contrast to 7 of 10 patients (70%) vaccinated longer than 3 years previously (P =.049). Among the 122 nonvaccinated patients, 41 (33.6%) were susceptible to measles: 4 of 47 patients (8.5%) within the first year after BM transplantation (BMT), and 37 of the 75 patients (49.3%) after the first year after BMT (P <.001). Eight recipients acquired measles, confirmed by serology (EIA). High-avidity IgG antibodies were observed in the acute phase of measles, suggesting a secondary immune response. Measles interstitial pneumonia was observed in one patient. Seven patients had mild symptoms. Exanthema was present in all patients. All but one patient had fever and nonproductive cough. Koplik spots could be observed in 5 patients. Measles can be mild in BM transplant recipients. Exanthema is frequently present but not often typical. Immunity to measles decreases after day +365 after BMT. Additional studies are needed to evaluate the safety of measles vaccine after the first year of BMT, mostly during outbreaks.

Micronutrients and child health: studies in international nutrition and HIV infection

Increasing data link micronutrient deficiencies to excess childhood morbidity and mortality, and similar relationships have been noted in the study of nutrition and HIV infection. We review epidemiologic studies that have examined the relationship between micronutrient deficiencies and health outcomes in childhood and HIV infection, as well as clinical trials of micronutrient supplementation. Vitamin A supplementation among communities at risk of deficiency effectively reduces mortality and morbidity in children younger than age 5, and vitamin A may be especially effective in HIV-infected children. Vertical transmission of HIV has not to date been affected by maternal micronutrient supplementation. In children with poor dietary zinc intake and/or bioavailability, zinc supplementation reduces the incidence and severity of diarrheal diseases, as well as the occurrence of pneumonia. Vitamin A therapy has not been associated with improved growth, whereas some trials have shown that zinc supplementation is associated with greater increments in height. Further trials of micronutrient supplementation are warranted.

Impaired bioavailability of vitamin A in adults and children with persistent diarrhoea in Zambia

BACKGROUND

We have previously demonstrated a strong relationship between low serum retinol concentration and mortality in Zambian AIDS patients with diarrhoea, but were unable to detect any benefit from oral micronutrient supplementation.

AIM

To test the hypothesis that this is related to impaired availability of vitamin A, we analysed serum retinol concentration changes over 6 h following oral mega-dose therapy (60, 120 or 180 mg retinol).

METHODS

Twenty-four men without diarrhoea, 15 adults with persistent diarrhoea and 11 children (six girls, five boys) with persistent diarrhoea were studied.

RESULTS

Men with persistent diarrhoea had lower baseline serum retinol concentrations (median 0.39 micromol/L, interquartile range 0.21-0.56) than controls (median 1.16 micromol/L, interquartile range 0.84-1.47; P=0.0003). After 60 mg retinol, the rise in serum retinol in HIV seropositive controls (median 0.63 micromol/L, interquartile range 0.35-0.77) did not differ significantly from that observed in HIV seronegative controls (median 0.35 micromol/L, interquartile range - 0.04-0.56; P=0.20). Increasing the dose to 120 mg or 180 mg retinol did not enhance the increase in serum retinol concentration. The increase in serum retinol was less in adults with persistent diarrhoea (median 0.25 micromol/L, interquartile range 0.04-0.35) and in children (median 0.11 micromol/L, interquartile range 0.04-0.46) than in men without diarrhoea (median 0.44 micromol/L, interquartile range 0.26-0.74; P=0.03). Adults and children with diarrhoea had greater losses of retinol in urine over a 24-h period than controls, but less than 1% of the ingested dose was excreted.

CONCLUSIONS

These results suggest that persistent diarrhoea in this population is associated with reduced bioavailability of retinol. Further work is required to determine the metabolic fate of therapeutic doses of retinol and to determine appropriate replacement strategies for HIV infected individuals.

Micronutrients as adjunct therapy of acute illness in children: impact on the episode outcome and policy implications of current findings

Role of micronutrients namely vitamin A, zinc and folate, as adjunct therapy of illness episodes in children in developing countries have been discussed in the light of health policy. Apart from a selective review, attempts have been made to statistically combine results of several studies to address policy issues. In children, vitamin A supplementation during illness has (a) a profound effect in reducing mortality in measles, (b) possibly a significant effect in reducing persistent diarrhea episodes in children with acute diarrhea, and (c) no benefit in pneumonia. Use of large dose vitamin A is recommended during measles episodes but not in non-measles pneumonia. Its use in acute diarrhea is debatable but recommended in persistent diarrhea and in severe malnutrition as a component of a micronutrient mixture. Large dose vitamin A supplementation should be used with caution in young infants as there are unresolved concerns about its safety particularly, bulging fontanelle observed in infants when co-administered at immunization. In children, zinc supplementation during illness, (a) had a marked effect in reducing prolonged episodes and a modest effect on episode duration in acute diarrhea, (b) resulted in reduced rate of treatment failure and death in persistent diarrhea, (c) had no effect in measles and non-measles pneumonia, and (d) probably had a detrimental effect of increasing death rate when a large dose was used in severely malnourished children. The desirability of routine zinc supplementation therapy of undernourished children with acute diarrhea should be assessed further. Concerning policy, zinc supplementation as a component of a micronutrient mixture is recommended in the rehabilitation of severely malnourished children and in persistent diarrhea. However, recommendation for its routine use in all cases of acute diarrhea in children needs additional studies on effectiveness, cost, operations and safety. In two randomized controlled trials folate has been evaluated in acute and persistent diarrhea and found to have no beneficial effect. Folate is not recommended as adjunct therapy of diarrhea. Role of folate in preventing severe disease and/or death deserves further evaluation.

Vitamin A supplementation: implications for morbidity and mortality in children

Vitamin A deficiency impairs epithelial integrity and systemic immunity and increases the incidence and severity of infections during childhood. However, findings from vitamin A supplementation trials are not consistent. Supplementation has resulted in significant reductions in mortality in several (but not all) large community-based trials among apparently healthy children. In hospital-based studies, vitamin A supplements have been consistently found to reduce the severity of measles infection, but no effect on nonmeasles respiratory infections has been observed. In some cases, the supplements were associated with an apparently increased risk of lower respiratory infection. Vitamin A supplements also reduced the severity of diarrhea in most (but not all) trials. Potential explanations for the differences in efficacy across trials are reviewed. While vitamin A supplementation is effective in reducing total mortality and complications from measles infections, it is likely to be more effective in populations suffering from nutritional deficiencies.

Malnutrition, morbidity and mortality in children and their mothers

While being underweight or stunted is recognized as an important risk factor for increased prevalence and severity of infection and high mortality rates, there is increasing evidence for an independent role for micronutrient deficiency. Improving vitamin A status reduces mortality among older infants and young children and reduces pregnancy-related mortality; it also reduces the prevalence of severe illness and clinic attendance among children. Improving Zn status reduces morbidity from diarrhoeal and respiratory infection. Treatment of established infection with vitamin A is effective in measles-associated complications, but is not as useful in the majority of diarrhoeal or respiratory syndromes. Zn supplements, however, have significant benefit on the clinical outcome of diarrhoeal and respiratory infections. Concerns that Fe supplements might increase morbidity if given in malarious populations appear to be decreasing, in the light of new studies on Fe supplements showing improved haemoglobin without an increase in morbidity. Breast-feeding, well known to protect against diarrhoea, is also important in protecting against respiratory infection, especially in the young infant. Transmission of human immunodeficiency virus (HIV) in breast milk is recognized, but new data showing reduced transmission in infants who receive exclusive breast-feeding rather than mixed feeding reinforces the importance of promoting this practice in areas where environmental contamination precludes the safe use of other infant feeding regimens. The presence of subclinical mastitis, now recognized to occur in approximately 20 % of mothers in several developing countries, has been shown to increase the concentration of HIV in breast milk. Preliminary findings suggest that the prevalence of subclinical mastitis is reduced by dietary supplements containing antioxidants. Governments and international agencies now have a strong scientific basis to be much more active and innovative in the introduction of focused nutrition interventions especially micronutrients, for the control of infection.

Nutrition and the eye

The topic "nutrition and the eye" cannot adequately be covered in a single review article; indeed, dozens of books and hundreds of articles have been written on the subject. This review concentrates on three areas in which specific nutrients are known or theorized to have a major impact on vision and the visual system: vitamin A deficiency; antioxidants and their proposed role in the prevention of age-related cataract and macular degeneration; and nutritional optic neuropathies, including those of the recent Cuban epidemic. In addition, this article touches on nutritional treatments that have been suggested for several less common eye diseases and, finally, considers several less prevalent conditions in which deficiency of or excess exposure to a particular nutrient has been associated with ocular pathology.

Simultaneous vitamin A administration at routine immunization contact enhances antibody response to diphtheria vaccine in infants younger than six months

A randomized, double-blind, placebo-controlled trial was conducted to evaluate the effect of simultaneous vitamin A supplementation and diphtheria, pertussis and tetanus (DPT) vaccination on the antibody levels. Infants aged 6-17 wk (n = 56) were randomly given 15 mg oral vitamin A or placebo at the time of their DPT immunization. Three such doses were given at monthly intervals. Immunoglobulin (Ig) G antibodies to diphtheria, pertussis and tetanus were assayed on enrollment and 1 mo after the third dose. Baseline antibody concentrations to diphtheria, pertussis and tetanus did not differ between the vitamin A-supplemented and placebo-treated groups. The postdose antibody to diphtheria level was significantly greater in the vitamin A than in the placebo-treated group. The geometric mean +/- SEM antibody levels (mg/L) were 22.9 +/- 1.2 and 11.0 +/- 1.3 in the vitamin A and placebo groups, respectively (P = 0.029). The postsupplementation concentrations of antibodies to pertussis and tetanus did not differ between the two groups. These results suggest that antibody response to diphtheria vaccination was potentiated by simultaneous vitamin A administration and DPT immunization.

The beneficial effects of weekly low-dose vitamin A supplementation on acute lower respiratory infections and diarrhea in Ecuadorian children

BACKGROUND

Previous studies of large-dose vitamin A supplementation on respiratory morbidity have produced conflicting results in a variety of populations. The influence of malnutrition has not been examined in the majority of these trials. We hypothesized that weekly low-dose vitamin A supplementation would prevent respiratory and diarrheal disease morbidity and that malnutrition might influence the efficacy of vitamin A supplementation.

METHODS

In a randomized, double-blind, placebo-controlled field trial of 400 children, 6 to 36 months of age in a high Andean urban slum, half of the children received 10 000 IU of vitamin A weekly and half received placebo for 40 weeks. Children were visited weekly at home by physicians and assessed for acute diarrheal disease and acute respiratory infections.

RESULTS

Acute diarrheal disease and acute respiratory infection did not differ globally or by severity between supplement-treated and placebo groups. However, the incidence of acute lower respiratory infection (ALRI) was significantly lower in underweight (weight-for-age z score [WAZ] <-2 SD) supplement-treated children than in underweight children on placebo (8.5 vs 22.3 per 10(3) child-weeks; rate ratio: 0.38 [95% CI: 0.17-0.85]). ALRI incidence was significantly higher in normal-weight (WAZ >-2 SD) supplement-treated children than in normal-weight children on placebo (9.8 vs 4.4 per 10(3) child-weeks; rate ratio: 2.21 [95% CI: 1.24-3.93]). By logistic regression analysis the risk of ALRI was lower in underweight supplement-treated children than in underweight children on placebo (point estimate 0.148 [95% CI: 0.034-0.634]). In contrast, risk of ALRI was higher in normal-weight supplement-treated children (WAZ >-1 SD to mean) than in normal-weight children on placebo in the same WAZ stratum (point estimate: 2.51 [95% CI: 1.24-5.05]). The risk of severe diarrhea was lower in supplement-treated children 18 to 23 months of age than in children on placebo in this age group (point estimate: 0.26 [95% CI: 0.06-1.00]).

CONCLUSIONS

Weekly low-dose (10 000 IU) vitamin A supplementation in a region of subclinical deficiency protected underweight children from ALRI and paradoxically increased ALRI in normal children with body weight over -1 SD. Protection from severe diarrhea was consistent with previous trials. Additional research is warranted to delineate potential beneficial and detrimental interactions between nutritional status and vitamin A supplementation regarding ALRI.

The impact of vitamin A supplementation given during a pneumonia episode on the subsequent morbidity of children

OBJECTIVE

To evaluate the impact of large-dose vitamin A supplementation given to infants > 6 months old (200000 IU) and to preschool children aged 1-4 years (400000 IU) during a pneumonia episode, on their subsequent morbidity and severe morbidity.

METHOD

In a randomized, double-blind, placebo controlled trial, the children were followed-up with 2-weekly visits at home for 16 weeks, with the first visit 2 weeks after treatment for pneumonia was initiated. The field workers asked about the presence of morbidity on the day of the visit and in the previous two weeks and about the occurrence and number of clinic attendances and hospital admissions since the last visit. They also measured the patients respiratory rate and temperature and assessed the children for the presence of cyanosis, chest indrawing and wheezing.

RESULTS

Except for the prevalence of diet refusal which was higher in the vitamin A group, no differences between the study groups were observed, either in the prevalence of morbidity or in the incidence of clinic attendances and hospital admissions.

CONCLUSION

No evidence was found for a beneficial effect of vitamin A given during acute pneumonia on the subsequent morbidity and severe morbidity of children in a population with marginal vitamin A deficiency.

New Issues in Developing Effective Approaches for the Prevention and Control of Vitamin A Deficiency

Even mild to moderate vitamin A deficiency is now recognized as an important factor in child health and survival. This has given increased emphasis to the goal of virtually eliminating vitamin A deficiency and its consequences, including blindness, by the end of the decade. The implications of vitamin A deficiency, however, vary according to the group at risk, and this needs to be addressed when looking at ways to achieve the goal. In pre-school children, vitamin A deficiency can lead to increased risk of mortality and morbidity and to blindness. In pregnant and lactating women, it can lead to night-blindness and appears to have implications for maternal morbidity and mortality. Although the immediate health consequences for schoolchildren and adolescents are not completely known, they are probably less dramatic. Nevertheless, it is clear that there is a cross-generational cycle leading to and perpetuating vitamin A deficiency in affected communities. This also has implications when addressing prevention and control strategies. The existing, somewhat successful approach has been to target children aged six months to six years; it is implicit that this criterion is used to measure progress towards the end-of-decade goals. A broader, complementary, life-cycle approach to vitamin A deficiency is now appropriate in many countries. There is increasing emphasis on such approaches, i.e., fortifying foods with vitamin A and improving the diet, which address the whole population at risk. A mix of interventions will give governments the chance to shift from a subsidized vitamin A capsule programme to more sustainable, non-subsidized, consumer-funded vitamin A interventions, although in an appreciable number of countries, supplementation with vitamin A will be a necessity for some years to come. Guidelines to assist governments in such transitions are a high priority.

Xerophthalmia and vitamin A status

The existence of 'fat-soluble A' has been known for over 80 years. But until recently clinicians were almost wholly absorbed by the ocular changes accompanying deficiency (xerophthalmia), and scientists with the vitamin's metabolic role in the rhodopsin cycle. The past two decades have witnessed a revolution in clinical and scientific concerns. Xerophthalmia is now recognized as a late manifestation of severe deficiency rather than of early, mild deficiency; as the mechanism responsible for half or more of all measles-associated blindness; and as the cause of half a million or more cases of pediatric blindness worldwide. Milder deficiency increases the severity of infectious morbidity, exacerbates iron deficiency anemia, retards growth, and is responsible for one to three million childhood deaths each year. Scientists are now busy unraveling vitamin A-dependent gene regulation to explain the myriad manifestations accompanying deficiency, while clinicians are designing and supervising programs to improve vitamin A status in over 60 countries, up from only three countries two decades ago. Control of vitamin A deficiency is now a major health challenge and goal of both UNICEF and the World Health Organization (WHO). Reaching that goal requires better parameters for assessing vitamin A status, increased understanding of metabolic pathways responsible for corneal dissolution (keratomalacia) and the molecular and cellular basis by which vitamin A status mediates resistance to infection. These issues are detailed elsewhere (Sommer and West, 1996).