A randomized trial of zinc nasal spray for the treatment of upper respiratory illness in adults

Zinc for prevention and treatment of the common cold

BACKGROUND

The common cold is an acute, self-limiting viral respiratory illness. Symptoms include nasal congestion and mucus discharge, sneezing, sore throat, cough, and general malaise. Given the frequency of colds, they are a public health burden and a significant cause of lost work productivity and school absenteeism. There are no established interventions to prevent colds or shorten their duration. However, zinc supplements are commonly recommended and taken for this purpose.

OBJECTIVES

To assess the effectiveness and safety of zinc for the prevention and treatment of the common cold.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, CINAHL, and LILACS to 22 May 2023, and searched Web of Science Core Collection and two trials registries to 14 June 2023. We also used reference checking, citation searching, and contact with study authors to identify additional studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in children or adults that tested any form of zinc against placebo to prevent or treat the common cold or upper respiratory infection (URTI). We excluded zinc interventions in which zinc was combined with other minerals, vitamins, or herbs (e.g. a multivitamin, or mineral supplement containing zinc).

DATA COLLECTION AND ANALYSIS

We used the Cochrane risk of bias tool to assess risks of bias, and GRADE to assess the certainty of the evidence. We independently extracted data. When necessary, we contacted study authors for additional information. We assessed zinc (type and route) with placebo in the prevention and treatment of the common cold. Primary outcomes included the proportion of participants developing colds (for analyses of prevention trials only), duration of cold (measured in days from start to resolution of the cold), adverse events potentially due to zinc supplements (e.g. unpleasant taste, loss of smell, vomiting, stomach cramps, and diarrhoea), and adverse events considered to be potential complications of the common cold (e.g. respiratory bacterial infections).

MAIN RESULTS

We included 34 studies (15 prevention, 19 treatment) involving 8526 participants. Twenty-two studies were conducted on adults and 12 studies were conducted on children. Most trials were conducted in the USA (n = 18), followed by India, Indonesia, Iran, and Turkey (two studies each), and Australia, Burkina Faso, Colombia, Denmark, Finland, Tanzania, Thailand, and the UK (one study each). The 15 prevention studies identified the condition as either common cold (n = 8) or URTI (n = 7). However, almost all therapeutic studies (17/19) focused on the common cold. Most studies (17/34) evaluated the effectiveness of zinc administered as lozenges (3 prevention; 14 treatment) in acetate, gluconate, and orotate forms; gluconate lozenges were the most common (9/17). Zinc gluconate was given at doses between 45 and 276 mg/day for between 4.5 and 21 days. Five (5/17) lozenge studies gave acetate lozenges and two (2/17) gave both acetate and gluconate lozenges. One (1/17) lozenge study administered intranasal (gluconate) and lozenge (orotate) zinc in tandem for cold treatment. Of the 17/34 studies that did not use lozenges, 1/17 gave capsules, 3/17 administered dissolved powders, 5/17 gave tablets, 4/17 used syrups, and 4/17 used intranasal administration. Most studies were at unclear or high risk of bias in at least one domain. There may be little or no reduction in the risk of developing a cold with zinc compared to placebo (risk ratio (RR) 0.93, 95% CI 0.85 to 1.01; I2 = 20%; 9 studies, 1449 participants; low-certainty evidence). There may be little or no reduction in the mean number of colds that occur over five to 18 months of follow-up (mean difference (MD) -0.90, 95% CI -1.93 to 0.12; I2 = 96%; 2 studies, 1284 participants; low-certainty evidence). When colds occur, there is probably little or no difference in the duration of colds in days (MD -0.63, 95% CI -1.29 to 0.04; I² = 77%; 3 studies, 740 participants; moderate-certainty evidence), and there may be little or no difference in global symptom severity (standardised mean difference (SMD) 0.04, 95% CI -0.35 to 0.43; I² = 0%; 2 studies, 101 participants; low-certainty evidence). When zinc is used for cold treatment, there may be a reduction in the mean duration of the cold in days (MD -2.37, 95% CI -4.21 to -0.53; I² = 97%; 8 studies, 972 participants; low-certainty evidence), although it is uncertain whether there is a reduction in the risk of having an ongoing cold at the end of follow-up (RR 0.52, 95% CI 0.21 to 1.27; I² = 65%; 5 studies, 357 participants; very low-certainty evidence), or global symptom severity (SMD -0.03, 95% CI -0.56 to 0.50; I² = 78%; 2 studies, 261 participants; very low-certainty evidence), and there may be little or no difference in the risk of a change in global symptom severity (RR 1.02, 95% CI 0.85 to 1.23; 1 study, 114 participants; low-certainty evidence). Thirty-one studies reported non-serious adverse events (2422 participants). It is uncertain whether there is a difference in the risk of adverse events with zinc used for cold prevention (RR 1.11, 95% CI 0.84 to 1.47; I2 = 0%; 7 studies, 1517 participants; very low-certainty evidence) or an increase in the risk of serious adverse events (RR 1.67, 95% CI 0.78 to 3.57; I2 = 0%; 3 studies, 1563 participants; low-certainty evidence). There is probably an increase in the risk of non-serious adverse events when zinc is used for cold treatment (RR 1.34, 95% CI 1.15 to 1.55; I2 = 44%; 2084 participants, 16 studies; moderate-certainty evidence); no treatment study provided information on serious adverse events. No study provided clear information about adverse events considered to be potential complications of the common cold.

AUTHORS' CONCLUSIONS

The findings suggest that zinc supplementation may have little or no effect on the prevention of colds but may reduce the duration of ongoing colds, with an increase in non-serious adverse events. Overall, there was wide variation in interventions (including concomitant therapy) and outcomes across the studies, as well as incomplete reporting of several domains, which should be considered when making conclusions about the efficacy of zinc for the common cold.

Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials

OBJECTIVE

To evaluate the benefits and risks of zinc formulations compared with controls for prevention or treatment of acute viral respiratory tract infections (RTIs) in adults.

METHOD

Seventeen English and Chinese databases were searched in April/May 2020 for randomised controlled trials (RCTs), and from April/May 2020 to August 2020 for SARS-CoV-2 RCTs. Cochrane rapid review methods were applied. Quality appraisals used the Risk of Bias 2.0 and Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Twenty-eight RCTs with 5446 participants were identified. None were specific to SARS-CoV-2. Compared with placebo, oral or intranasal zinc prevented 5 RTIs per 100 person-months (95% CI 1 to 8, numbers needed to treat (NNT)=20, moderate-certainty/quality). Sublingual zinc did not prevent clinical colds following human rhinovirus inoculations (relative risk, RR 0.96, 95% CI 0.77 to 1.21, moderate-certainty/quality). On average, symptoms resolved 2 days earlier with sublingual or intranasal zinc compared with placebo (95% CI 0.61 to 3.50, very low-certainty/quality) and 19 more adults per 100 were likely to remain symptomatic on day 7 without zinc (95% CI 2 to 38, NNT=5, low-certainty/quality). There were clinically significant reductions in day 3 symptom severity scores (mean difference, MD -1.20 points, 95% CI -0.66 to -1.74, low-certainty/quality), but not average daily symptom severity scores (standardised MD -0.15, 95% CI -0.43 to 0.13, low-certainty/quality). Non-serious adverse events (AEs) (eg, nausea, mouth/nasal irritation) were higher (RR 1.41, 95% CI 1.17 to 1.69, NNHarm=7, moderate-certainty/quality). Compared with active controls, there were no differences in illness duration or AEs (low-certainty/quality). No serious AEs were reported in the 25 RCTs that monitored them (low-certainty/quality).

CONCLUSIONS

In adult populations unlikely to be zinc deficient, there was some evidence suggesting zinc might prevent RTIs symptoms and shorten duration. Non-serious AEs may limit tolerability for some. The comparative efficacy/effectiveness of different zinc formulations and doses were unclear. The GRADE-certainty/quality of the evidence was limited by a high risk of bias, small sample sizes and/or heterogeneity. Further research, including SARS-CoV-2 clinical trials is warranted.

PROSPERO REGISTRATION NUMBER

CRD42020182044.

Phytopharmaceuticals mediated Furin and TMPRSS2 receptor blocking: can it be a potential therapeutic option for Covid-19?

BACKGROUND

Currently, novel coronavirus disease (Covid-19) outbreak creates global panic across the continents, as people from almost all countries and territories have been affected by this highly contagious viral disease. The scenario is deteriorating due to lack of proper & specific target-oriented pharmacologically safe prophylactic agents or drugs, and or any effective vaccine. drug development is urgently required to back in the normalcy in the community and to combat this pandemic.

PURPOSE

Thus, we have proposed two novel drug targets, Furin and TMPRSS2, as Covid-19 treatment strategy. We have highlighted this target-oriented novel drug delivery strategy, based on their pathophysiological implication on SARS-CoV-2 infection, as evident from earlier SARS-CoV-1, MERS, and influenza virus infection via host cell entry, priming, fusion, and endocytosis. STUDY DESIGN &  METHODS: An earlier study suggested that Furin and TMPRSS2 knockout mice had reduced level of viral load and a lower degree of organ damage such as the lung. The present study thus highlights the promise of some selected novel and potential anti-viral Phytopharmaceutical that bind to Furin and TMPRSS2 as target.

RESULT

Few of them had shown promising anti-viral response in both preclinical and clinical study with acceptable therapeutic safety-index.

CONCLUSION

Hence, this strategy may limit life-threatening Covid-19 infection and its mortality rate through nano-suspension based intra-nasal or oral nebulizer spray, to treat mild to moderate SARS-COV-2 infection when Furin and TMPRSS2 receptor may initiate to express and activate for processing the virus to cause cellular infection by replication within the host cell and blocking of host-viral interaction.

Safety and Efficacy of 0.5% Carbomer 980 Gel for Treatment of Symptoms of Common Cold: Results of 2 Randomized Trials

BACKGROUND

Two studies of intranasal 0.5% carbomer 980 gel were conducted evaluating nasal tolerability in healthy volunteers and safety and efficacy in adults with common cold symptoms.

METHODS

Study 1 randomly assigned healthy adults to 0.5% carbomer 980 gel (n = 20) or placebo (n = 10) administered intranasally four times daily for 7 days. Nasal examinations were conducted at baseline and daily throughout the study. The primary endpoint was local nasal tolerability. Study 2 randomly assigned adults with an investigator-confirmed diagnosis of symptomatic common cold to 0.5% carbomer 980 gel (n = 87) or placebo (n = 81), administered intranasally four times daily for 7 days (except for day 1, where subjects who received their first dose mid-day administered only three doses). The primary efficacy endpoint was the average nasal symptom score over days 1‒4 (ANSS_1-4). Secondary efficacy endpoints included ANSS over days 1‒7 and average total symptom score (ATSS). Adverse events (AEs) were recorded throughout the study.

RESULTS

In study 1, subjects assigned to 0.5% carbomer 980 gel had no mucosal grading higher than grade 1B (superficial nasal mucosal erosion) and low incidences of mucosal bleeding and crusting. In study 2, there were no statistically significant differences between treatments for any efficacy endpoints. Active treatment was well-tolerated; the most commonly reported AEs were headache, myalgia, and cough.

CONCLUSION

While 0.5% carbomer 980 gel nasal spray demonstrated good local nasal tolerability in healthy volunteers, the spray did not significantly impact the course of infection or resolution of cold symptoms in subjects with common cold.

Anosmia after Intranasal Zinc Gluconate Use

Background

Zinc is an essential mineral. Beneficial zinc absorption takes place via enteral, parenteral, or cutaneous routes. However, direct application to the olfactory epithelium has been reported to cause loss of smell. Recently, intranasal zinc gluconate has been recommended as a treatment for the common cold. Severe posttreatment hyposmia and anosmia have been observed.

Methods

The case report of a typical patient is presented and analyzed in detail, followed by a series of patients with severe hyposmia or anosmia after the use of intranasal zinc gluconate.

Results

Although interindividual variation in drug response and drug effect is apparent, the severe hyposmia or anosmia appears to be long lasting or permanent in some cases. The mechanism of olfactory loss is thought to be the direct action of the divalent zinc ion on the olfactory receptor cell.

Conclusions

Zinc ions are toxic to olfactory epithelium. Reports of severe hyposmia with parosmia or anosmia have occurred after intranasal use of zinc gluconate.

Partitioned log-rank tests for the overall homogeneity of hazard rate functions

In survival analysis, it is routine to test equality of two survival curves, which is often conducted by using the log-rank test. Although it is optimal under the proportional hazards assumption, the log-rank test is known to have little power when the survival or hazard functions cross. To test the overall homogeneity of hazard rate functions, we propose a group of partitioned log-rank tests. By partitioning the time axis and taking the supremum of the sum of two partitioned log-rank statistics over different partitioning points, the proposed test gains enormous power for cases with crossing hazards. On the other hand, when the hazards are indeed proportional, our test still maintains high power close to that of the optimal log-rank test. Extensive simulation studies are conducted to compare the proposed test with existing methods, and three real data examples are used to illustrate the commonality of crossing hazards and the advantages of the partitioned log-rank tests.

Influence of zinc supplementation on histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen during subchronic exposure of Wistar rats to glyphosate

A subchronic toxicity study was carried out to determine the glyphosate-induced histopathological changes in the stomach, liver, kidney, brain, pancreas and spleen of rats and the attendant ameliorative effect when pretreated with zinc at the dose rate of 50 mg/kg body weight. The rats were exposed to two doses of the glyphosate (375 and 14.4 mg/kg body weight) for the period of 8 weeks which was the duration of the study, and some groups were exposed to the glyphosate after pretreatment with zinc. The histopathological changes recorded during the study were only in the rats exposed to the glyphosate at the dose rate of 375 mg/kg body weight except the vacuolation encountered in the brains and haemosiderosis in the spleens of rats exposed to zinc alone. Degenerated mucosal epithelial cells which involved the muscularis mucosa and the glands in the stomachs of rats were seen microscopically. Hepatic cells degeneration especially at the portal areas of the livers of rats was observed. The histopathological examination of the kidneys showed glomerular degeneration, mononuclear cells infiltration into the interstices of the tubules and tubular necrosis. The conspicuous changes seen in the brains were neuronal degeneration. Pancreatic acinar cells were degenerated while the spleen of the rats showed depopulated splenic cells in both the red and the white pulps. It was concluded that zinc supplementation in rats prior to glyphosate exposure ameliorated the histopathological changes observed in the stomach, liver, kidney, brain, pancreas and spleen with no observable alteration in the histoarchitecture in the organs of the zinc-supplemented rats.

Serum biochemical assessment of hepatic and renal functions of rats during oral exposure to glyphosate with zinc

A subchronic toxicity study was carried out to assess hepatic and renal functions of rats during oral exposure to glyphosate with zinc for the period of 8 weeks. Forty-eight Wistar rats used for the study were randomized into six groups of eight Wistar rats each, and each group had equal number of male and female Wistar rats. The Wistar rats administered with distilled water at 2 ml/kg body weight served as the control group (DW); others were administered with zinc at 50 mg/kg body weight (Z) group, glyphosate at 375 mg/kg body weight (G) group, a combination of zinc and glyphosate at 50 and 375 mg/kg body weight, respectively (Z + G), group, glyphosate at 14.4 mg/kg body weight (GC) group, and a combination of zinc and glyphosate at 50 and 14.4 mg/kg body weight, respectively (Z + GC), group. At the end of the study, blood samples were collected from each rats; from which, sera samples were obtained and assayed for total protein, albumin, alanine and aspartate aminotransferases, alkaline phosphatase, Na⁺, K⁺, Cl⁻, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{HCO}_3^{-} $$\end{document}, Ca²⁺, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{PO}_4^{-} $$\end{document}, urea and creatinine using autoanalyzer, and globulin was calculated. The albumin concentration was significantly high (p < 0.05) in GC group compared to DW group, and this change was ameliorated following supplementation with zinc. The total protein and globulin concentrations did not differ significantly between the groups (p > 0.05), and the relative changes were ameliorated by supplementation with zinc. The alkaline phosphatase activity was relatively low in GC group; however, supplementation with zinc in Z + GC group made it to be significantly high (p < 0.05) compared to GC group. The alanine and aspartate aminotransferases in G and GC groups were relatively high compared to DW group, which were ameliorated by supplementation with zinc. The relatively low Ca²⁺ concentration in G and GC groups compared to DW were ameliorated in Z + G group, and it was significantly high in Z + GC group at p < 0.01 compared to DW, p < 0.001 compared to G and GC groups and p < 0.05 compared to Z + G group. There were only slight changes in the electrolytes concentrations (Na⁺, K⁺, Cl⁻, \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{HCO}_3^{-} $$\end{document} and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \mathrm{PO}_4^{-} $$\end{document}), which were differentially ameliorated by zinc supplementation. The reasons for the various changes recorded were discussed. It was concluded that subchronic oral exposure to glyphosate caused both hepatic and renal functions toxicity in rats, which were ameliorated by zinc supplementation.

Respiratory viruses other than influenza virus: impact and therapeutic advances

Though several antivirals have been developed and marketed to treat influenza virus infections, the development of antiviral agents with clinical activity against other respiratory viruses has been more problematic. Here we review the epidemiology of respiratory viral infections in immunocompetent and immunocompromised hosts, examine the evidence surrounding the currently available antivirals for respiratory viral infections other than influenza, highlight those that are in the pipeline, and discuss the hurdles for development of such agents.

Effect of zinc sulfate on common cold in children: randomized, double blind study

BACKGROUND

The aim of the present randomized, double-blind, placebo-controlled study was to determine the efficacy of zinc sulfate on the duration and severity of common cold in children.

METHODS

Children presenting at least two of 10 symptoms of common cold within the 24-48 h of the onset of illness were eligible for the study. Children were randomized to receive either oral zinc containing zinc sulfate or placebo. A diary was completed to record symptoms and adverse effects. Symptoms were scored as absent (0), mild (1), moderate (2), or severe (3).

RESULTS

One hundred and fifty children participated in the study, and 120 children were included in the final analysis. The median duration of all cold symptoms was 6 days (P = 0.20), and the median duration of nasal symptoms was 5 days in both groups (P = 0.09). However, total symptom severity scores were significantly lower in the zinc group, starting from the second day of the study. The lower scores in the zinc group were largely due to improvement of nasal symptom scores. Adverse effects were similar in both groups.

CONCLUSION

Zinc sulfate had no effect on the duration of cold symptoms. However, it appears to be effective in reducing the severity of the cold symptoms in healthy children.

Treatment of naturally acquired common colds with zinc: a structured review

BACKGROUND

Over the past 20 years, the use of zinc as an over-the-counter alternative therapy for the common cold has vastly grown in popularity. Recent reports of potentially permanent anosmia caused by intranasal zinc therapy warrant careful analysis of the therapeutic effects of zinc.

METHODS

A search of the Medline database (including articles published during 1966-2006) for studies of zinc and the common cold produced 105 published reports. Fourteen were randomized, placebo-controlled studies that examined the effect of zinc lozenges, nasal sprays, or nasal gels on naturally acquired common colds. Eleven features of experimental design affecting signal quality, chance, bias, and blinding were used to evaluate the 14 placebo-controlled studies. These criteria were validated case definition, quantifiable hypothesis, sample size calculation, randomized assignment, double blinding, proof of blinding, measurement of compliance, measurement of dropout rate, analysis by intent to treat, description of methods of analysis, and measurements of probability. Equal weight was given to each criterion, because failure to meet any one could potentially invalidate the findings of a clinical trial.

RESULTS

Four studies met all 11 criteria. Three of these studies reported no therapeutic effect from zinc lozenge or nasal spray. One study reported positive results from zinc nasal gel. Of the remaining 10 studies, 6 reported a positive effect and 4 reported no effect. Intent-to-treat analysis was the most common criterion not met.

CONCLUSIONS

This structured review suggests that the therapeutic effectiveness of zinc lozenges has yet to be established. One well-designed study did report a positive effect of zinc nasal gel.

Blinded trials taken to the test: an analysis of randomized clinical trials that report tests for the success of blinding

BACKGROUND

Blinding can reduce bias in randomized clinical trials, but blinding procedures may be unsuccessful. Our aim was to assess how often randomized clinical trials test the success of blinding, the methods involved and how often blinding is reported as being successful.

METHODS

We analysed a random sample of blinded randomized clinical trials indexed in the The Cochrane Central Register of Controlled Trials and published in 2001. We identified 1599 blinded trials, and noted if they had conducted any test for the success of blinding. We also selected 200 trials randomly that did not report any such test, and sent a questionnaire to the corresponding authors asking them if they had conducted any tests.

RESULTS

Thirty-one out of 1599 trials (2%) reported tests for the success of blinding. Test methods varied, and reporting was generally incomplete. Blinding was considered successful in 14 out of the 31 trials (45%) and unclear in 10 (32%). Of the seven trials (23%) reporting unsuccessful blinding the risk of a biased trial result was either not addressed or was discounted in six cases. We received 130 questionnaires from trial authors (65%) of which 15 (12%) informed that they had conducted, but not published, tests.

CONCLUSIONS

Blinding is rarely tested. Test methods vary, and the reporting of tests, and test results, is incomplete. There is a considerable methodological uncertainty how best to assess blinding, and an urgent need for improved methodology and improved reporting.

Comparing two crossing hazard rates by Cox proportional hazards modelling

Motivated by a clinical trial of zinc nasal spray for the treatment of the common cold, we consider the problem of comparing two crossing hazard rates. A comprehensive review of the existing methods for dealing with the crossing hazard rates problem is provided. A new method, based on modelling the crossing hazard rates, is proposed and implemented under the Cox proportional hazards framework. The main advantage of the proposed method is the utilization of the Box-Cox transformation which covers a wide range of hazard crossing patterns. Simulation studies are conducted for comparing the performance of the existing methods and the proposed one, which show that the proposed method outperforms some of its peers in certain cases. Applications to a kidney dialysis patients data and the zinc nasal spray clinical trial data are discussed.

Intranasal Zinc in the Management of the Common Cold

Because zinc ions may prevent rhinovirus from attaching to and infecting cells in the nasal cavity, it has been recently hypothesized that direct application of ionic zinc to the nasal mucosa would be effective in reducing the duration of rhinovirus-associated colds. Five studies that compare intranasal zinc to placebo were identified in the medical literature. These studies provide conflicting results and are reviewed in detail. In the clinical trials that found efficacy, intranasal zinc was administered within the first 24 to 48 hours of the onset of cold symptoms. Adverse effects reported in clinical trials include nasal stinging or burning, epistaxis, headache, dry nose, dry mouth, nasal irritation, throat irritation, and nasal pain. Also of importance, case reports of intranasal zinc—induced persistent anosmia (complete loss of the sense of smell) have been reported in the literature. It is important that pharmacists inform their patients who want to use intranasal zinc of this possible complication.

The prophylactic and therapeutic effectiveness of zinc sulphate on common cold in children

AIM

To determine the efficacy of prophylactic administration of zinc sulphate in reducing the occurrence of the common cold in children, and to evaluate the efficacy of zinc sulphate in reducing the duration and severity of cold symptoms.

METHODS

A total of 200 healthy children were randomly assigned to receive oral zinc sulphate (zinc group, n=100) or placebo (placebo group, n=100). Zinc sulphate (15 mg of zinc) or placebo syrup were administered for prophylaxis once daily during a 7-mo study period. The dose was increased to two times per day (30 mg of zinc) at the onset of cold, until symptoms resolved.

RESULTS

The mean number of colds in the zinc group was significantly less than in the placebo group (1.2 vs 1.7 colds per child; p=0.003). The mean cold-related school absence was 0.9 d per child in the zinc group versus 1.3 d in the placebo group (p=0.04). Compared to the placebo group, the zinc group had shorter mean duration of cold symptoms and decreased total severity scores for cold symptoms (p<0.0001). Adverse effects were mild and similar in both groups.

CONCLUSION

Zinc sulphate appears to be an easily administered, safe and well-tolerated alternative for the prevention and treatment of the common cold in children.

Efficacy of zinc against common cold viruses: an overview

Objective

To review the laboratory and clinical evidence of the medicinal value of zinc for the treatment of the common cold.

Data Sources

Published articles identified through Medline (1980–2003) using the search terms zinc, rhinovirus, and other pertinent subject headings. Additional sources were identified from the bibliographies of the retrieved articles.

Study Selection

By the author.

Data Extraction

By the author.

Data Synthesis

Human rhinoviruses, by attaching to the nasal epithelium via the intracellular adhesion molecule-1 (ICAM-1) receptor, cause most colds. Ionic zinc, based on its electrical charge, also has an affinity for ICAM-1 receptor sites and may exert an antiviral effect by attaching to the ICAM-1 receptors in the rhinovirus structure and nasal epithelial cells. Clinical tests of zinc for treatment of common colds have been inconsistent, primarily because of study design, blinding, and lozenge contents. Early formulations of lozenges also were unpalatable. In three trials with similar study designs, methodologies, and efficacy assessments, zinc effectively and significantly shortened the duration of the common cold when it was administered within 24 hours of the onset of symptoms. Recent reports of trials with zinc gluconate administered as a nasal gel have supported these findings; in addition, they have shown that treatment with zinc nasal gel is effective in reducing the duration and severity of common cold symptoms in patients with established illness.

Conclusion

Clinical trial data support the value of zinc in reducing the duration and severity of symptoms of the common cold when administered within 24 hours of the onset of common cold symptoms. Additional clinical and laboratory evaluations are warranted to further define the role of ionic zinc for the prevention and treatment of the common cold and to elucidate the biochemical mechanisms through which zinc exerts its symptom-relieving effects.

Preventive and curative effects of acupuncture on the common cold: a multicentre randomized controlled trial in Japan

OBJECTIVE

To determine the preventive and curative effects of manual acupuncture on the symptoms of the common cold.

METHOD

Students and staff in five Japanese acupuncture schools (n=326) were randomly allocated to acupuncture and no-treatment control groups. A specific needling point (Y point) on the neck was used bilaterally. Fine acupuncture needles were gently manipulated for 15 s, evoking de qi sensation. Acupuncture treatments were performed four times during the 2-week experimental period with a 2-week follow-up period. A common cold diary was scored daily for 4 weeks, and a common cold questionnaire was scored before each acupuncture treatment and twice at weekly intervals. A reliability test for the questionnaire was performed on the last day of recording.

RESULTS

Five of the 326 subjects who were recruited dropped out. The diary score in the acupuncture group tended to decrease after treatment, but the difference between groups was not significant (Kaplan-Meier survival analysis, log rank test P=0.53, Cox regression analysis, P>0.05). Statistically significantly fewer symptoms were reported in the questionnaire by the acupuncture group than control group (P=0.024, general linear model, repeated measure). Significant inter-centre (P<0.001, general linear model) and sex (P=0.027, general linear model) differences were also detected. Reliability tests indicated that the questionnaire with 15 items was sufficiently reliable. No severe adverse event was reported.

CONCLUSION

This is the first report of a multi-centre randomized controlled trial of acupuncture for symptoms of the common cold. A significantly positive effect of acupuncture was demonstrated in the summed questionnaire data, although a highly significant inter-centre difference was observed. Needling on the neck using the Japanese fine needle manipulating technique was shown to be effective and safe. The use of acupuncture for symptoms of the common cold symptoms should be considered, although further evidence from placebo controlled RCTs is required.

The common cold: a review of the literature

Respiratory viral infections, also known as the common cold, are the most common infections in humans. Despite their benign nature, they are a major cause of morbidity and mortality on a worldwide basis. Several viruses have been associated with such illness, of which rhinovirus is the most common. Symptom production is a combination of viral cytopathic effect and the activation of inflammatory pathways. Therefore, antiviral treatment alone may not be able to prevent these events. The optimal use of such agents also requires earlier initiation; therefore, it is important to develop accurate and rapid diagnostic techniques for respiratory viruses. Before any reliable and effective treatment is available, symptomatic therapies may remain the only possible choice of management.