***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract Objective : To evaluate the effect of simultaneous zinc and vitamin A supplementation on  diarrhoea and acute lower respiratory infections in children . Study design : R and omised double blind placebo controlled trial . Setting : Urban slums of Dhaka , Bangladesh . Participants and methods : 800 children aged 12 - 35 months were r and omly assigned to one of four intervention groups : 20 mg zinc once daily for 14 days ; 200 000 IU vitamin A , single dose on day 14 ; both zinc and vitamin A ; placebo . The children were followed up once a week for six months , and morbidity information was collected . Results : The incidence and prevalence of diarrhoea were lower in the zinc and vitamin A groups than in the placebo group . Zinc and vitamin A interaction had a rate ratio ( 95 % confidence interval ) of 0.79 ( 0.66 to 0.94 ) for the prevalence of persistent diarrhoea and 0.80 ( 0.67 to 0.95 ) for dysentery . Incidence ( 1.62 ; 1.16 to 2.25 ) and prevalence ( 2.07 ; 1.76 to 2.44 ) of acute lower respiratory infection were significantly higher in the zinc group than in the placebo group . The interaction term had rate ratios of 0.75 ( 0.46 to 1.20 ) for incidence and 0.58 ( 0.46 to 0.73 ) for prevalence of acute lower respiratory infection . Conclusions : Combined zinc and vitamin A synergistically reduced the prevalence of persistent diarrhoea and dysentery . Zinc was associated with a significant increase in acute lower respiratory infection , but this adverse effect was reduced by the interaction between zinc and vitamin A. What is already known on this topic Trials of vitamin A supplementation have failed to show a beneficial effect on morbidity in children Experimental studies have shown that , in the presence of zinc deficiency , vitamin A supplementation fails to reverse vitamin A deficiency Coexistence of deficiencies of zinc and vitamin A could be a reason for the failure of vitamin A supplementation , but data in humans are limited What this paper adds Combined zinc and vitamin A supplementation is more effective in reducing persistent diarrhoea and dysentery than either vitamin A or zinc alone Zinc alone increased respiratory illnesses , but interaction between zinc and vitamin A reduced this adverse There is uncertainty over whether vitamin A supplementation reduces morbidity among children with sub clinical deficiency of the vitamin . Hence a double-blind , placebo-controlled trial of the effect of vitamin A supplementation on  childhood morbidity  was conducted among 11,124 children aged 6 - 83 months in the northwest of Haiti . After a r and om start , children were sequentially assigned by household units to receive either megadose vitamin A or placebo in three distribution cycles 4 months apart . 2 to 8 weeks after each administration of the vitamin A and placebo capsules , indicators of childhood morbidity were reassessed through interviews conducted in the homes of participating families . The vitamin A group was found to have an increased 2-week prevalence of all symptoms and signs of childhood morbidity assessed , including diarrhoea ( rate ratio [ RR ] = 1.09 , 95 % confidence interval 1.05 - 1.14 ) , rhinitis ( RR = 1.02 , 95 % confidence interval 1.00 - 1.04 ) , cold/flu symptoms ( RR = 1.04 , 95 % confidence interval 1.01 - 1.06 ) , cough ( RR = 1.07 , 95 % confidence interval 1.03 - 1.11 ) , and rapid breathing ( RR = 1.18 , 95 % confidence interval 1.09 - 1.27 ) . The study shows an increased 2-week prevalence of diarrhoea and the symptoms of respiratory infections after vitamin A supplementation OBJECTIVES --To determine whether a single high dose of vitamin A given to all children in communities with high mortality and malnutrition could affect mortality and to assess whether periodic community wide supplementation could be readily incorporated into an ongoing primary health programme . DESIGN --Opportunistic controlled trial . SETTING --Jumla district , Nepal . SUBJECTS -- All children aged under 5 years ; 3786 in eight subdistricts given single dose of vitamin A and 3411 in remaining eight subdistricts given no supplementation .  MAIN OUTCOME MEASURES --Mortality and cause of death in the five months after supplementation . RESULTS --Risk of death for children aged 1 - 59 months in supplemented communities was 26 % lower ( relative risk 0.74 , 95 % confidence interval 0.55 to 0.99 ) than in unsupplemented communities . The reduction in mortality was greatest among children aged 6 - 11 months : death rate ( deaths/1000 child years at risk ) was 133.8 in supplemented children and 260.8 in unsupplemented children ( relative risk 0.51 , 0.30 to 0.89 ) . The death rate from diarrhoea was also reduced ( 63.5 supplemented v 97.5 unsupplemented ; relative risk 0.65 , 0.44 to 0.95 ) . The extra cost per death averted was about $ 11 . CONCLUSION --The results support a role for Vitamin A in increasing child survival . The supplementation programme was readily integrated with the ongoing community health programme at little extra cost The authors assessed the efficacy of the World Health Organization ( WHO ) recommendation of 200,000 IU of vitamin A in oil to treat acute non-xerophthalmic measles patients . Acute measles patients who did not require hospitalization were enrolled in a r and omized , double-masked , clinical trial of vitamin A ( n=90 ) versus placebo ( n=110 ) carried out in Ndola , Zambia , in 1991 . Measles-associated morbidity was defined by the presence of signs and symptoms of acute respiratory infection . Daily evaluations for the first 3 days were followed by weekly visits for a month at urban health centers . Baseline demographic , clinical , and biochemical characteristics were similar in both groups . Cross-sectional analysis of morbidity status , by group , at each weekly evaluation showed no significant differences until week 4 , when more placebo-treated patients had cough or pneumonia ( p=0.005 ) . However , longitudinal analysis , which looked at changes among individuals and controlled for initial health status , showed more equivocal results . The odds ratio for the development of pneumonia in patients with measles cough in vitamin A-treated subjects was 0.73 ( 95 % confidence interval ( Cl ) 0.30 - 1.80 ) . The odds ratio for the development of measles-associated cough or pneumonia in asymptomatic measles patients was 0.52 ( 95 % Cl 0.24 - 1.13 ) , in favor of vitamin A , but the odds ratio for failing to improve from pneumonia in vitamin A-treated subjects was 1.23 ( 95 % Cl 0.68 - 2.3 ) , a result in favor of placebo . These results suggest that the evidence for the efficacy of one dose of vitamin A in oil to prevent measles complications is not as strong as that previously shown for two 200,000 IU doses of water-miscible vitamin A , and that the WHO recommendation may need to be reexamined BACKGROUND R and omized controlled trials have shown inconsistent responses of childhood pneumonia to the use of vitamin A as an adjunct to the st and ard treatment of pneumonia . OBJECTIVE We evaluated the effect of a moderate dose of vitamin A as an adjunct to st and ard 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 r and omly 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 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 r and omly 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 Vitamin A supplementation of population s of vitamin A-deficient preschool-age children has been shown to reduce childhood mortality , but the primary preventive effects of such supplements on childhood infectious diseases have not been carefully evaluated . We conducted an individually r and omized , placebo-controlled , double-masked trial among 1,407 Indonesian preschool-age children , to measure the effects of high dose vitamin A on acute respiratory and diarrheal illnesses . Signs and symptoms of morbidity were monitored using every other day home surveillance by trained interviewers . High dose vitamin A supplements increased the incidence of acute respiratory illnesses ( ARI ) by 8 % , and acute lower respiratory illnesses ( ALRI ) by 39 % . These detrimental effects on acute lower respiratory illnesses were most marked in children with adequate nutritional status ( rate ratio 1.83 , 95 % confidence interval 1.257 - 2.669 ) . In contrast , vitamin A tended to be protective of ALRI in chronically malnourished children ( rate ratio 0.71 , 95 % confidence interval 0.375 - 1.331 ) . There was no overall effect of high-dose vitamin A supplements on the incidence of diarrheal disease ( rate ratio 1.06 , 95 % confidence interval 0.920 - 1.225 ) . However , we found a significant interaction between supplementation and age : vitamin A increased the incidence of diarrhea in children < 30 mo of age , but tended to reduce the incidence in older children . The finding of a significant adverse effect of vitamin A supplements in adequately nourished children highlights the need to review the criteria for selecting population s of preschool-age children for vitamin A supplementation At immunization contact , 165 infants 2.5 mo old were r and omly assigned to receive either 15 mg vitamin A ( retinyl palmitate ) or placebo . Three doses were given at monthly intervals with each diphtheria , pertussis , tetanus and oral polio ( DPT/OPV ) immunization dose . The diarrhea and acute respiratory infection ( ARI ) morbidity was similar in the vitamin A and placebo groups . However , the duration ( days per child-year , mean + /- SD ) of ARI was less in 
    Output:
    
There is evidence for vitamin A supplements to prevent acute LRTIs in children with low serum retinol or those with a poor nutritional status