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

Measles outbreaks in Micronesia, 1991 to 1994

BACKGROUND

Several islands in Micronesia experienced large measles outbreaks, during 1991 through 1994. Except for Guam, none of the islands had reported measles outbreaks during the previous 20 years.

METHODS

To characterize the outbreaks, measles surveillance data, hospital records and death certificates were reviewed. Preoutbreak vaccination coverage rates were assessed by reviewing public health vaccination records. Viral isolates were genetically sequenced to determine the source of transmission. Linear regression analysis was performed to assess the effectiveness of outbreak control measures.

RESULTS

Between 1991 and 1994 more than 1300 measles cases and 16 measles-related deaths were reported in Micronesia. Preoutbreak vaccination coverage rates among 2-year-old children were 55 to 94%. Genetic sequencing of the viral isolates and epidemiologic investigations suggested transmission between islands and new importations from outside of Micronesia. The highest attack rates were among children ages < 5 years (20/1000) and 10 to 19 years (38/1000). Compared with attack rates among children ages < 1 and 10 to 19 years, attack rates were lower among those ages 5 to 9 years, in whom 2-dose vaccination coverage rates were highest (P < 0.001). Early and rapid implementation of mass vaccination campaigns was significantly associated with shorter duration of outbreaks (P = 0.049).

CONCLUSION

The measles outbreaks in Micronesia show that island populations may be highly susceptible to measles. High two-dose vaccination coverage levels must be maintained to prevent such outbreaks. Early and rapidly implemented mass measles vaccination campaigns were effective in control of island outbreaks. Strengthening public health infrastructure and surveillance is necessary for early identification of outbreaks and rapid implementation of mass campaigns.

The dynamics of measles epidemics

The interepidemic interval (T) of measles in London from 1647 to 1837 evolved progressively from 5-yearly to 2-yearly by 1800. Measles mortality was significantly ( p<0.001) cross-correlated with the annual wheat prices, a good index of nutrition although at a 2-year lag. Epidemics correlated with low autumn temperatures (p<0. 001). A linearised model of the dynamics of epidemics shows that T is determined by the product of population (N) and susceptibility (beta) and that the system will settle at its steady state unless the epidemics are driven. It is suggested that (i) the progressive change in T was caused by a rise in population size (N) and an increased susceptibility (beta) related to malnutrition and (ii) epidemics were driven by oscillations in low autumn temperature (p<0. 001) and by cycles of susceptible young children produced by malnutrition during pregnancy.

High dose vitamin A supplementation in the course of pneumonia in Vietnamese children

We carried out a randomized, placebo-controlled, double-blinded trial to evaluate the effect on morbidity of high dose oral vitamin A, given on hospital admission to 592 children aged 1-59 months with moderate and severe pneumonia. Severely underweight children were not included, but 45% were moderately underweight. The vitamin A and placebo groups were comparable in baseline characteristics. Four patients died. Among all of the surviving children, no differences were found regarding mean time for normalization of fever, respiratory rate and time of hospitalization. Stratification for moderate malnutrition, degree of pneumonia, age and sex revealed moderately malnourished vitamin A-supplemented children to have a shorter time of hospitalization (p = 0.04), due to an effect in females aged > 12 months (p = 0.02) and females with very severe pneumonia (p = 0.048). This study indicates that, in developing countries like Vietnam, supplementation with vitamin A in children with pneumonia could shorten the recovery rate in the ones that are undernourished, especially females > 1 y old.

Identifying areas with vitamin A deficiency: the validity of a semiquantitative food frequency method

OBJECTIVES

The prevalence of vitamin A deficiency has traditionally been assessed through xerophthalmia or biochemical surveys. The cost and complexity of implementing these methods limits the ability of nonresearch organizations to identify vitamin A deficiency. This study examined the validity of a simple, inexpensive food frequency method to identify areas with a high prevalence of vitamin A deficiency.

METHODS

The validity of the method was tested in 15 communities, 5 each from the Philippines, Guatemala, and Tanzania. Serum retinol concentrations of less than 20 micrograms/dL defined vitamin A deficiency.

RESULTS

Weighted measures of vitamin A intake six or fewer times per week and unweighted measures of consumption of animal sources of vitamin A four or fewer times per week correctly classified seven of eight communities as having a high prevalence of vitamin A deficiency (i.e., 15% or more preschool-aged children in the community had the deficiency) (sensitivity = 87.5%) and four of seven communities as having a low prevalence (specificity = 57.1%).

CONCLUSIONS

This method correctly classified the vitamin A deficiency status of 73.3% of the communities but demonstrated a high false-positive rate (42.9%).

Integrated management of childhood illness by outpatient health workers: technical basis and overview. The WHO Working Group on Guidelines for Integrated Management of the Sick Child

This article describes the technical basis for the guidelines for the integrated management of childhood illness (IMCI), which are presented in the WHO/UNICEF training course on IMCI for outpatient health workers at first-level health facilities in developing countries. These guidelines include the most important case management and preventive interventions against the leading causes of childhood mortality--pneumonia, diarrhoea, malaria, measles and malnutrition. The training course enables health workers who use the guidelines to make correct decisions in the management of sick children. The guidelines have been refined through research studies and field-testing in the Gambia, Ethiopia, Kenya, and United Republic of Tanzania, as well as studies on clinical signs in the detection of anaemia and malnutrition. These studies, and two others from Uganda and Bangladesh, are presented in this Supplement to the Bulletin of the World Health Organization.

Prevention of diarrhoea in young children in developing countries

An updated review of nonvaccine interventions for the prevention of childhood diarrhoea in developing countries is presented. The importance of various key preventive strategies (breast-feeding, water supply and sanitation improvements) is confirmed and certain aspects of others (promotion of personal and domestic hygiene, weaning education/food hygiene) are refined. Evidence is also presented to suggest that, subject to cost-effectiveness examination, two other strategies-vitamin A supplementation and the prevention of low birth weight-should be promoted to the first category of interventions, as classified by Feachem, i.e. those which are considered to have high effectiveness and strong feasibility.

Clinical problems in measles case management

Measles remains one of the leading causes of childhood morbidity and mortality in developing countries. The World Health Organization has identified effective case management as one of the specific strategies to reduce the burden of this disease. The purpose of this article is to review the aetiology, natural history, treatment and outcome of the common clinical problems associated with measles with a view to identifying possible deficiencies in case management. Complications such as pneumonia, diarrhoea, croup and malnutrition have been well defined in terms of their relative contribution to morbidity and mortality. However, there are few published data on the aetiology and natural history of these specific complications. Such data are crucial for rational case management strategies. Data on treatment of measles and its complications are limited and the role of antibiotic prophylaxis and therapy is unclear. The only specific research focus on case management during the last decade has been vitamin A therapy. There is a continuing need for community and hospital-based studies on the natural history of measles and its complications, the aetiology of these complications and intervention strategies that will improve measles case management.

Vitamin A therapy for children with respiratory syncytial virus infection: a multicenter trial in the United States

BACKGROUND

High dose vitamin A therapy is effective in reducing morbidity and mortality associated with measles infection. Children with acute respiratory syncytial virus (RSV) infection have low serum vitamin A concentrations.

METHODS

We performed a multicenter, randomized, placebo-controlled trial of high dose vitamin A therapy among 239 children 1 month to 6 years of age to determine whether high dose vitamin A therapy would reduce morbidity associated with RSV infection.

RESULTS

There were no differences between the vitamin A and placebo recipients for most clinical outcomes; however, vitamin A recipients had-longer hospital stays than placebo recipients (5.0 days vs. 4.4 days, P = 0.01) after enrollment. This effect was significant for children who were older than 1 year (who also had received the highest doses of vitamin A), particularly among those at low risk for complications of RSV infection and those enrolled during the second study season. Serum retinol levels at enrollment were inversely correlated with severity of illness.

CONCLUSIONS

We found no evidence of a beneficial effect of vitamin A for the treatment of RSV infection in children in the United States. There may be groups of children for which vitamin A has an adverse effect, resulting in longer hospital stays.

Treatment of respiratory syncytial virus infection with vitamin A: a randomized, placebo-controlled trial in Santiago, Chile

BACKGROUND

Treatment with high dose vitamin A reduces complications and duration of hospitalization for children with measles. In respiratory syncytial virus (RSV) infection, as with measles, low serum vitamin A concentrations correlate with increased severity of illness.

METHODS

To determine whether high dose vitamin A treatment is also effective for treating RSV disease, we conducted a randomized, double blind, placebo-controlled trial among 180 RSV-infected children between 1 month and 6 years of age at three hospitals in Santiago, Chile. Children with nasal washes positive for RSV antigen were given oral vitamin A (50,000 to 200,000 IU of retinyl palmitate, doses according to age; n = 89) or placebo (n = 91) within 2 days of admission.

RESULTS

There was no significant benefit from vitamin A treatment for the overall group in duration of hospitalization, need for supplemental oxygen or time to resolve hypoxemia. For the subgroup of children with significant hypoxemia on admission (room air oxygen saturation level < or = 90%), those given vitamin A had more rapid resolution of tachypnea (P = 0.01) and a shorter duration of hospitalization (5.5 vs. 9.3 days, P = 0.09). No toxicities were seen, including excess vomiting or bulging fontanel.

CONCLUSIONS

If vitamin A has a beneficial effect on the course of RSV disease, it may be seen only in more severely ill children.

A to Z: vitamin A and zinc, the miracle duo

Dietary micronutrients such as vitamins and trace minerals are known modulators of host immune responses against common pathogens. In this respect, vitamin A and zinc have recently received increased attention. Several in vivo and in vitro studies suggest that vitamin A may be a critical player in the mucosal immune responses in the respiratory and gastrointestinal tracts, particularly in undernourished children. The effect may be mediated primarily by stabilization of the membrane of mucosal epithelial cells, as well as enhanced leukocyte functions. The beneficial effect of vitamin A therapy in reducing measles-associated morbidity and mortality suggests its crucial role in defenses against viral pathogens. Zinc is also known affect leukocyte functions such as phagocytosis and T-lymphocyte-mediated immune responses. However, unlike vitamin A, zinc has been investigated primarily for its effects on bacterial infections. Dietary supplementation or therapeutic treatment with vitamin A and zinc may be a cheap yet effective means of preventing or treating infections in highly susceptible populations. Additional studies, however, are required to better define the types of pathogens and the specific human populations that may benefit from such therapy.

Nutrition and immunity with emphasis on infection and autoimmune disease

Nutrition and nutritional status can have profound effects on immune functions, resistance to infection and autoimmunity in man and other animals. Nutrients enhance or depress immune function depending on the nutrient and level of its intake. Protein-energy malnutrition and vitamin A deficiency are strongly associated with impaired immunity and infectious disease. The essential role vitamin A plays in infection and maintenance of mucosal surfaces has long been known. Recent evidence shows that T-cell subpopulations, cytokines and antibody subclasses are all affected by vitamin A. In animal studies supplementation with vitamin E protects against infection and is linked to stimulatory effects on the immune system. In man vitamin E and other anti-oxidants increase the number of CD4+ cells. Dietary lipids and zinc have a substantial impact on autoimmunity from protective to potentiation of immuno-pathological processes in animals. There is considerable potential to modify human autoimmune disease by manipulation of lipid nutrition. Deficiency of pyridoxine induces atrophy of lymphoid organs, marked reduction in lymphocyte numbers, impairs antibody responses and IL-2 production. Dietary copper is important in the prevention of infection in some animal species and T-cell function is defective under deficiency states due to an inability to produce IL-2. Selenium has been linked to viral infection, enhanced T-cell functions and TNF beta induced increase in natural killer cell activity. Understanding the molecular and cellular immunological mechanisms involved in nutrient-immune interactions will increase our applications for nutrition of the immune system in health and in disease

Plasma retinol level, vitamin A supplementation and acute respiratory infections in children of 1-5 years old in a developing country. Respiratory Diseases Working Group

STUDY OBJECTIVE

To evaluate the relationship between vitamin A supplementation, plasma retinol level (PRL) and incidence, severity and duration of acute respiratory infect ions (ARI) in children 1-5 years old.

DESIGN AND SETTING

A one year prospective randomized intervention study from June 1989 to May 1990 in Cikutra, a suburb of Bandung, Indonesia.

SUBJECTS AND MEASUREMENTS

Out of almost 2000 children aged 12-54 months, 269 were selected by stratified randomization. Vitamin A (200,000 IU orally) was administered at 6-monthly intervals in a double blind, placebo controlled programme. Every 2 weeks, primary health care workers collected data on respiratory symptoms in the children, and every month a pediatrician examined the children. Venous blood samples were obtained at the start and at 3 and 6 months for plasma retinol levels (PRL).

RESULTS

The mean PRL at the start of the study was 20 +/- 8 micrograms/dl; 8% of the children showed a deficient level of less than 10 micrograms/dl. The incidence or ARI was 6.7 +/- 3.5 episodes per child per year with a mean duration of 5.3 +/- 3.1 days per episode. In vitamin A supplemented children the duration of ARI was slightly shorter (5.2 +/- 3.1 versus 5.6 +/- 3.1 days, P < 0.01) but no effect on the incidence or severity of ARI was detected. Low, and especially deficient, PRL had improved after 3 months and even after 6 months, but this was unrelated to vitamin A supplementation. There was also no relationship between PRL and incidence, severity or duration of ARI.

CONCLUSIONS

Only a slight relationship is found between vitamin A supplementation and ARI duration in under-fives.

Assumptions and contradictions in measles and measles immunization research: is measles good for something?

Measles infection, the major cause of childhood mortality among infections preventable by immunization, has been considered to kill mainly young and malnourished children. Assuming that mainly 'weak' children are saved by immunizations, it has been speculated that the impact on survival of immunization is likely to be limited because the malnourished children are more prone to die of other infections. However, recent studies from developing countries have suggested that host factors may not be the most important determinants of acute and long-term mortality after measles infection. Instead, it was found that infection contracted after exposure at home infection contracted from someone outside the home. Furthermore, measles is particularly severe if contracted from someone of the opposite sex. Hence transmission factors, in particularly intensity of exposure and cross-sex transmission, may be more important determinants of measles mortality than the determinants of measles mortality than the host factors usually emphasized. Consistent with these observations and in contrast to assumptions about 'weak' children dying, immunization is associated with a major reduction in mortality. Since measles immunization is associated with a 30% reduction in mortality or more, the impact is much larger than should be expected from the proportion of all deaths attributed to measles. It has therefore been suggested that measles immunization may prevent the persistent immunosuppression and delayed mortality assumed to be associated with measles. However, several observations contradict the common understanding that the function of measles immunization is only to prevent the acute and long-term mortality associated with measles infection. Recently, the high-titre measles immunization recommended by WHO was found to be associated with reduced survival for female recipients compared with girls who have received the standard low-dose measles vaccine, and this difference in survival was not due to suboptimal protection against measles infection. Contrary to usual assumptions. against measles infection. Contrary to usual assumptions, standard low-dose measles vaccine reduces mortality even more when given before 9 months of age, the age currently recommended by WHO. The beneficial impact of standard vaccine is apparently temporary, lasting 1 to 2 years, whereas it should increase with the age of the child. The beneficial effect seems to be particularly strong for girls. The most likely interpretation of these observations, is that standard low-dose measles vaccine has a non-specific beneficial effect. Contrary to current assumptions, children who survive the acute phase of measles infection may have a survival advantage compared with unimmunized, uninfected children.(ABSTRACT TRUNCATED AT 400 WORDS)

Aflatoxin and outcome from acute lower respiratory infection in children in The Philippines

Aflatoxin is immunosuppressive in experimental conditions. This study addressed its potentially contributory role in the poor outcome of acute lower respiratory infections (ALRI) in children in The Philippines. The catchment area included peri-urban slums and middle-class housing. One hundred and fifteen children (mean age 2.1, range 0.08-12 years) were enrolled and their serum and urine obtained at presentation with ALRI. Aflatoxins in serum and aflatoxin metabolites in urine were measured by previously validated ELISA tests. Using the 1986 WHO criteria for the severity of ALRI, 31% had mild, 12% moderate, 49% severe and 8% severe complicated pneumonia. Eighty of 97 (82%) chest radiographs were abnormal. Ninety per cent of the children were below average weight for age, using Filipino standards, with a mean of 79% (range 27-157%). Thirteen (11%) children died. Aflatoxin in their serum, reflecting recent ingestion, was detected in 33%, with a mean positive value of 462 pg/ml. Aflatoxin metabolites (reflecting chronic ingestion) were detected in 64 of 65 urines collected, with a mean value of 0.1-4.77ng/ml. None of the children with detectable serum aflatoxin died. Anorexia and impaired consciousness were strongly associated with a poor outcome (prolonged fever or death). There was a strong association between undetectable serum aflatoxin concentrations and death (p = 0.004), perhaps reflecting anorexia. There was no relationship between the concentration of urinary aflatoxin metabolites and outcome. Serum was also obtained from 29 mothers on admission and none contained detectable aflatoxin. As virtually all the children had evidence of exposure to aflatoxin, a potentially immunosuppressive role in the context of pneumonia cannot be excluded.

Clinical trial of vitamin A as adjuvant treatment for lower respiratory tract infections

OBJECTIVE

To test the efficacy of a high dose of vitamin A as adjuvant treatment for radiographically confirmed cases of acute lower respiratory tract infection (ALRI).

DESIGN

Randomized, double-masked, placebo-controlled clinical trial.

SETTING

Two large urban hospitals in Guatemala City.

PATIENTS

Sequential sample of 263 children aged 3 to 48 months, identified in the emergency departments and admitted to the hospital.

INTERVENTIONS

Vitamin A (100,000 IU for children less than 1 year of age, and 200,000 IU for older children) or placebo in addition to standard treatment for ALRI which included antibiotics, oxygen, bronchodilators, and intravenously administered solutions.

MEASUREMENTS AND MAIN RESULTS

The children were assessed every 8 hours. There were neither statistically nor clinically significant differences by treatment group in the rate of normalization in respiratory rate, oxygen saturation, temperature, or clinical score. Duration of hospitalization was not different by treatment group. Adverse outcomes (mechanical ventilation, prolonged hospitalization, readmission or transfer, and death) were equally distributed between the two groups.

CONCLUSIONS

Treatment with high doses of vitamin A over and above standard care for infants and children with non-measles-related ALRI is not efficacious for the current episode. Additional trials among populations in which vitamin A deficiency is more prevalent and severe should be considered.

Safety and pharmacokinetics of vitamin A therapy for infants with respiratory syncytial virus infections

Infants with respiratory syncytial virus infection have low serum vitamin A levels. We treated 21 respiratory syncytial virus-infected children with 12,500 to 25,000 IU of oral vitamin A. Vitamin A levels were normalized at 6 h, and none of the children experienced vitamin A toxicity or exacerbation of respiratory illness. Vitamin A treatment of previously healthy respiratory syncytial virus-infected infants at these doses is safe and well tolerated.

The decline of admissions for xerophthalmia at Cicendo Eye Hospital, Indonesia, 1981-1992

Xerophthalmia due to vitamin A deficiency is a leading cause of blindness in children and has been a serious problem in Indonesia. To determine whether progress has been made in the eradication of xerophthalmia, we assessed hospital admissions for xerophthalmia at Cicendo Eye Hospital, Bandung, Indonesia. The hospital admission registry from 1981 to 1992 was reviewed. Between January 1981 and December 1992, there were 117 admissions for xerophthalmia, and of these, 63 were boys and 54 were girls, with an average age of 3.9 +/- 0.3 years. Hospital admissions for xerophthalmia declined steeply from 1981 to 1985, with a few rare cases from 1985 through 1992. During the same period from 1981 through 1992, there were no overall changes in total hospital admissions or total pediatric admissions. These results suggest that xerophthalmia is becoming less common in Indonesia.

Potential interventions for the prevention of childhood pneumonia in developing countries: a meta-analysis of data from field trials to assess the impact of vitamin A supplementation on pneumonia morbidity and mortality. The Vitamin A and Pneumonia Working Group

Reported are the results of a meta-analysis (12 large-scale field trials in seven countries) of the impact of vitamin A supplementation on pneumonia morbidity and mortality, undertaken as part of a wider review process of a range of possible potential interventions for the prevention of childhood pneumonia. The summary estimate of the relative risk for the impact of vitamin A supplementation on pneumonia incidence was 0.95 (95% confidence interval (CI) = 0.89, 1.01), and for pneumonia mortality, 0.98 (95% CI = 0.75, 1.28). This is in marked contrast to the substantial impact of vitamin A supplementation on all-cause mortality (combined rate ratio (RR) = 0.77, 95% CI = 0.71, 0.84), and on diarrhoea-specific and measles-specific mortality. There was no evidence for a differential impact on pneumonia mortality by age. Since the majority of pneumonia deaths occur in the first year of life, we complemented the paucity of data on pneumonia-specific mortality among this age group with a detailed examination of all-cause mortality among infants. The mortality reduction in the 6-11 month age group was consistent with that observed for older age groups (RR = 0.69; 95% CI = 0.54, 0.90), but there was no reduction for 0-5 month-olds (RR = 0.97; 95% CI = 0.73, 1.29).

The epidemiology of measles: thirty years of vaccination

Measles is a highly infectious disease which has a major impact on child survival, particularly in developing countries. The importance of understanding the epidemiology of this disease is underlined by its ability to change rapidly in the face of increasing immunization coverage. Much is still to be learned about measles epidemiology and the best strategies for administering measles vaccines, as well as about the biological mechanisms of action of measles vaccines. However, it is clear that tremendous progress can be made in preventing death and disease from measles with existing knowledge about the disease, and by using the presently available vaccines and applying well tried methods of treating cases. Research in the coming decade may provide improved strategies and more effective vaccines for use in immunization programmes.

Impact of massive dose of vitamin A given to preschool children with acute diarrhoea on subsequent respiratory and diarrhoeal morbidity

OBJECTIVE

To assess the impact of vitamin A supplementation on morbidity from acute respiratory tract infections and diarrhoea.

DESIGN

Double blind randomised placebo controlled field trial.

SETTING

An urban slum area in New Delhi, India.

SUBJECTS

900 children aged 12-60 months attending a local health facility for acute diarrhoea of less than seven days' duration randomly allocated to receive vitamin A 200,000 IU or placebo.

MAIN OUTCOME MEASURES

Incidence and prevalence of acute lower respiratory tract infections and diarrhoea during the 90 days after termination of the enrolment diarrhoeal episode measured by twice weekly household surveillance.

RESULTS

The incidence (relative risk 1.07; 95% confidence interval 0.92 to 1.26) and average number of days spent with acute lower respiratory tract infections were similar in the vitamin A supplementation and placebo groups. Among children aged 23 months or less there was a significant reduction in the incidence of measles (relative risk 0.06; 95% confidence interval 0.01 to 0.48). The incidence of diarrhoea was also similar (relative risk 0.95; 0.86 to 1.05) in the two groups. There was a 36% reduction in the mean daily prevalence of diarrhoea associated with fever in the vitamin A supplemented children older than 23 months.

CONCLUSIONS

Results were consistent with a lack of impact on acute lower respiratory tract related mortality after vitamin A supplementation noted in other trials and a possible reduction in the severity of diarrhoea.

Serum vitamin A levels in respiratory syncytial virus infection

Respiratory syncytial virus causes worldwide epidemics of respiratory disease. Of 23 children infected with respiratory syncytial virus, 65% had low serum concentrations of vitamin A during acute illness; these low values were associated with more severe illness. Vitamin A supplementation may have a role in the management of infection with respiratory syncytial virus.

Clinical and laboratory features of measles in hospitalized adults

PURPOSE

Description of the epidemiology, morbidity, and mortality of hospitalized adults with typical measles.

PATIENTS AND METHODS

Retrospective case analysis of 33 adults who required acute care for complications of measles in a public hospital in Los Angeles, California. The diagnosis of measles was established on standard clinical or serologic grounds.

RESULTS

Of 68 patients (age greater than 14) with signs and symptoms of measles who presented for medical care, 33 (19 males and 14 females) required hospitalization; 18 were natives of the United States. The patient age was 26.1 +/- 7.3 (mean +/- SD) years; four patients, all natives of the U.S., were born before 1957. The duration of hospitalization was 6.8 +/- 8.8 days for all patients and 13.4 +/- 14.2 days for the nine patients who required intensive care unit (ICU) care. Six of the ICU patients required mechanical ventilation for 11.0 +/- 15.0 days; two deaths occurred among these patients. During the course of their illness, 7 of 25 (28%), 11 of 28 (39%), 6 of 28 (21%), and 5 of 16 patients (31%) had peak lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, and creatine kinase values, respectively, that were greater than 5 times the upper limit of normal. Fifteen of 28 patients (54%) developed total serum calcium levels less than or equal to 2.0 mmol/L. Ten cases were serologically confirmed; 23 cases were diagnosed as probable measles on clinical grounds. There were no significant demographic, clinical, or laboratory differences between patients with confirmed and probable measles. No patients had characteristic manifestations of atypical measles. The sole immunocompromised patient died.

CONCLUSIONS

Measles in adults may result in severe, life-threatening complications that utilize substantial medical resources. Physicians need to appreciate the clinical presentations and manifestations of severe measles in adults and to provide measles vaccine to nonimmune adults during community-wide outbreaks.

Physiological role of antioxidants in the immune system

Diets contain naturally occurring antioxidant compounds that can stabilize highly reactive, potentially harmful molecules called free radicals. Free radicals are generated during normal cellular metabolism and result from the metabolism of certain drugs or xenobiotics. Exposure to UV light, cigarette smoke, and other environmental pollutants also increases the body's free radical burden. The harmful activities of free radicals are associated with damage to membranes, enzymes, and DNA. The ability of antioxidants to destroy free radicals protects the structural integrity of cells and tissues. This review focuses on data indicating that the functions of the human immune system depend on the intake of micronutrients, which can act as antioxidants. Recent clinical trials have found that antioxidant supplementation can significantly improve certain immune responses. Specifically, supplementation with vitamins C, E, and A or beta-carotene increased the activation of cells involved in tumor immunity in the elderly. Supplementation with the antioxidant vitamins also protected immune responses in individuals exposed to certain environmental sources of free radicals. Supplementation with vitamin A, a relatively weak antioxidant, decreases morbidity and mortality associated with measles infections in children.

Vitamin A supplementation in infectious diseases: a meta-analysis

OBJECTIVE

To study the effect of vitamin A supplementation on morbidity and mortality from infectious disease.

DESIGN

A meta-analysis aimed at identifying and combining mortality and morbidity data from all randomised controlled trials of vitamin A.

RESULTS

Of 20 controlled trials identified, 12 trials were randomised trials and provided "intention to treat" data: six community trials in developing countries, three in children admitted to hospital with measles, and three in very low birth weight infants. Combined results for community studies suggest a reduction of 30% (95% confidence interval 21% to 38%; two tailed p < 0.0000001) in all cause mortality. Analysis of cause specific mortality showed a reduction in deaths from diarrhoeal disease (in community studies) by 39% (24% to 50%; two tailed p < 0.00001); from respiratory disease (in measles studies) by 70% (15% to 90%; two tailed p = 0.02); and from other causes of death (in community studies) by 34% (15% to 48%; two tailed p = 0.001). Reductions in morbidity were consistent with the findings for mortality, but fewer data were available.

CONCLUSIONS

Adequate supply of vitamin A, either through supplementation or adequate diet, has a major role in preventing morbidity and mortality in children in developing countries. In developed countries vitamin A may also have a role in those with life threatening infections such as measles and those who may have a relative deficiency, such as premature infants.

Etiology of corneal opacification in central Tanzania

The frequency and causes of visually significant corneal opacification in central Tanzania was assessed by a population-based survey. The overall prevalence of bilateral corneal opacification was 1.16% (95% CI 0.31-1.44) and unilateral corneal opacification was 2.07% (95% CI 1.55-2.73). Bilateral corneal opacification was most frequently associated with trachoma, keratoconjunctivitis, vitamin A deficiency and measles. Unilateral corneal opacification had similar causes with the addition of cases caused by trauma. Corneal scarring is a frequent occurrence in this region. The majority of cases of corneal opacification are secondary to potentially preventable or treatable causes.

Low serum retinol is associated with increased severity of measles in New York City children

Children with no known prior vitamin A deficiency exhibited a significant decline in their serum retinol levels during the acute phase of measles. This decline in circulating retinol was associated with increased duration of fever, higher hospitalization rates, and decreased antibody titers.

Vitamin A supplementation and child survival

Previous studies of the effect of 6-monthly vitamin A supplementation on child mortality have given conflicting results. In other trials, more frequent doses of vitamin A have significantly reduced mortality among children at risk of vitamin A deficiency. We have done a double-blind, placebo-controlled trial of vitamin A supplementation in the Sudan among 28,753 children aged 9-72 months at risk of vitamin A deficiency. Children were assigned to receive either 200,000 IU vitamin A and 40 IU vitamin E every 6 months (vitamin A group) or 40 IU vitamin E alone (placebo group). During the 18 months of follow-up, there were 120 deaths (8.4/1000) in the vitamin A group and 112 (7.9/1000) in the placebo group (relative risk 1.06, 95% confidence interval 0.82-1.37). Controlling for geographic site, round of observation, anthropometry, morbidity, dietary intake of vitamin A, sex, and all baseline differences between the two groups did not change the results. Children living in poor and unsanitary environments, younger children, and those sick, stunted, wasted, or consuming diets low in vitamin A were at a significantly higher risk of dying. The lack of an effect of large-dose vitamin A supplementation on mortality, despite a clear association between dietary vitamin A and mortality, underscores the need to identify factors that modify the efficacy of vitamin A supplements as a public-health measure. Reducing poverty, improvements in sanitation, and access to adequate diets should remain the main goals to improve child survival.

Vitamin A levels in children with measles in Long Beach, California

Studies from Africa suggest that vitamin A supplementation may reduce morbidity and mortality rates associated with measles among poorly nourished children. We studied 20 children with measles in Long Beach, Calif., and found that 50% (95% confidence interval; 28% to 72%) were vitamin A deficient. This frequency among presumably well nourished American children supports evaluation of vitamin A status as a part of acute management of measles in the United States.

Vitamin A deficiency and attributable mortality among under-5-year-olds

Reported are estimates of the prevalence in developing countries of physiologically significant vitamin A deficiency and the number of attributable deaths. The WHO classification of countries by the severity and extent of xerophthalmia was used to categorize developing countries by likely risk of subclinical vitamin A deficiency. Using vital statistics compiled by UNICEF, we derived population figures and mortality rates for under-5-year-olds. The findings of vitamin A supplementation trials were applied to populations at-risk of endemic vitamin A deficiency to estimate the potential impact of improved vitamin A nutriture in reducing mortality during preschool years. Worldwide, over 124 million children are estimated to be vitamin A deficient. Improved vitamin A nutriture would be expected to prevent approximately 1-2 million deaths annually among children aged 1-4 years. An additional 0.25-0.5 million deaths may be averted if improved vitamin A nutriture can be achieved during the latter half of infancy. Improved vitamin A nutriture alone could prevent 1.3-2.5 million of the nearly 8 million late infancy and preschool-age child deaths that occur each year in the highest-risk developing countries.

Measles

Measles has become epidemic over most of the world, with an important increase in the number of cases and associated morbidity and mortality in the United States since 1986. The two major factors responsible for this rise in the number of cases are, first, the increase in unvaccinated preschool-age children and, second, vaccine nonresponders (approximately 5%). The highest attack rate occurred in teenagers (15 to 19 years old) and in nine states (82% of cases). This situation has prompted revised immunization recommendations for those counties reporting more than five cases of measles among preschool-age children during each of the previous 5 years. In these counties, a first dose with monovalent measles vaccine is recommended at 9 months of age, followed by a second dose with measles, mumps, and rubella vaccine at 15 months of age, and revaccination of all children at the time of school entry. Recent publications regarding the use of vitamin A and certain antiviral agents are encouraging and are discussed in the manuscript. All cases of measles should be reported and investigated promptly. A good outbreak-control program will depend on the rapid recognition of the disease, a team approach, and prompt vaccination or IgG administration to susceptible persons.

Efficacy of vitamin A in reducing preschool child mortality in Nepal

Community trials of the efficacy of vitamin A supplementation in reducing preschool childhood mortality have produced conflicting results. To resolve the question, a randomised, double-masked, placebo-controlled community trial of 28,630 children aged 6-72 months was carried out in rural Nepal, an area representative of the Gangetic flood plain of South Asia. Randomisation was carried out by administrative ward; the vitamin-A-supplemented children received 60,000 retinol equivalents every 4 months and placebo-treated children received identical capsules containing 300 retinol equivalents. After 12 months, the relative risk of death in the vitamin-A-supplemented compared with the control group was 0.70 (95% confidence interval 0.56-0.88), equivalent to a 30% reduction in mortality. The trial, which had been planned to last 2 years, was discontinued. The reduction in mortality was present in both sexes (relative risk for boys 0.77; for girls 0.65), at all ages (range of relative risks 0.83-0.50), and throughout the year (0.76-0.67). The reduction in mortality risk was not affected by acute nutritional status, as measured by arm circumference. Thus, periodic vitamin A delivery in the community can greatly reduce child mortality in developing countries.

Plasma vitamin A and carotene in maternal and cord blood

Mean plasma vitamin A and carotene levels in 200 pregnant women at term were 30.3 mcg% and 43.6 mcg%. Sixty-four percent of women had vitamin A in lower limit of normal (less than 33 mcg%) and 26% had deficient and low levels of carotene. Mean values of plasma vitamin A and carotene in cord blood was 13.7 mcg% and 16.5 mcg%, respectively, and lower than that of maternal blood at term. Women who had adequate levels of vitamin A (greater than 33 mcg%) in blood had significantly higher intake of vitamin A. Similarly the newborn babies of those mothers who had adequate levels of vitamin A had significantly higher levels of vitamin A than those of mothers who had inadequate levels (less than 33 mcg%).