Browsing by Subject "common cold"

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  • Niemi, Peter (Helsingin yliopisto, 2017)
    The aims of this study are to determine the prevalence of clinically apparent orolabial herpes and the rate of recrudescence in the Finnish population. As a secondary aim we evaluate the significance of sociodemographic, health-related and other factors previously associated with the disease. The study sample was collected from the Finnish population register office using simple random sampling. A mailed questionnaire was sent to 3200 adults and 1000 children in 1989-1990. Response rate was excellent. In the adult study sample (15-65 years old) the lifetime prevalence of recurrent herpes labialis is 19.4%. Over 60% of cases have 1-3 relapses per year. Family background and health factors are found to be independent predictive factors for recurrent herpes labialis: mother (OR 3.38; 95% CI 2.35 – 4.86), chapped lips (OR 3.28; 95% CI 2.39 - 4.49). A larger proportion of women than men have the disease (OR 2.17; 95% CI 1.70 – 2.77). In order to develop the management of the disease further studies on the role of factors affecting the clinical manifestation, symptomatic and asymptomatic latency reactivation are needed.
  • Hemilä, Harri; Chalker, Elizabeth (2021)
    In this individual patient data meta-analysis we examined datasets of two randomized placebo-controlled trials which investigated the effect of nasal carrageenan separately on children and adults. In both trials, iota-carrageenan was administered nasally three times per day for 7 days for patients with the common cold and follow-up lasted for 21 days. We used Cox regression to estimate the effect of carrageenan on recovery rate. We also used quantile regression to calculate the effect of carrageenan on colds of differing lengths. Nasal carrageenan increased the recovery rate from all colds by 54% (95% CI 15%-105%; p = .003). The increase in recovery rate was 139% for coronavirus infections, 119% for influenza A infections, and 70% for rhinovirus infections. The mean duration of all colds in the placebo groups of the first four quintiles were 4.0, 6.8, 8.8, and 13.7 days, respectively. The fifth quintile contained patients with censored data. The 13.7-day colds were shortened by 3.8 days (28% reduction), and 8.8-day colds by 1.3 days (15% reduction). Carrageenan had no meaningful effect on shorter colds. In the placebo group, 21 patients had colds lasting over 20 days, compared with six patients in the carrageenan group, which corresponds to a 71% (p = .003) reduction in the risk of longer colds. Given that carrageenan has an effect on diverse virus groups, and effects at the clinical level on two old coronaviruses, it seems plausible that carrageenan may have an effect on COVID-19. Further research on nasal iota-carrageenan is warranted.
  • Hemilä, Harri; Chalker, Elizabeth (2021)
    A Commentary on: The Long History of Vitamin C: From Prevention of the Common Cold to Potential Aid in the Treatment of COVID-19. A review of the effects of vitamin C on the immune system and respiratory tract infections was recently published (1). We are the authors of a review of vitamin C and the common cold (2), which was cited in the article. We consider that some of the authors’ statements are inaccurate and here we describe the issues on which we disagree.
  • Hemilä, Harri (1997)
    Although the role of vitamin C in common cold incidence had been studied extensively, the level of vitamin C intake has not been unequivocally shown to affect the incidence of colds. In the present study the six largest vitamin C supplementation (> or = 1 g/d) studies, including over 5000 episodes in all, have been analysed, and it is shown that common cold incidence is not reduced in the vitamin C-supplemented groups compared with the placebo groups (pooled rate ratio (RR) 0.99; 95% CI 0.93, 1.04). Consequently these six major studies give no evidence that high-dose vitamin C supplementation decreases common cold incidence in ordinary people. Nevertheless, the analysis was continued with the hypothesis that vitamin C intake may affect common cold susceptibility in specific groups of people. It was assumed that the potential effect of supplementation might be most conspicuous in subjects with low dietary vitamin C intake. The average vitamin C intake has been rather low in the UK and plasma vitamin C concentrations are in general lower in males than in females. In four studies with British females vitamin C supplementation had no marked effect on common cold incidence (pooled RR 0.95; 95% CI 0.86, 1.04). However, in four studies with British male schoolchildren and students a statistically highly significant reduction in common cold incidence was found in groups supplemented with vitamin C (pooled RR 0.70; 95% CI 0.60, 0.81). Thus, these studies with British males indicate that vitamin C intake has physiological effects on susceptibility to common cold infections, although the effect seems quantitatively meaningful only in limited groups of people and is not very large.
  • Hemilä, Harri; Carr, Anitra; Chalker, Elizabeth (2021)
    Given the previous research on vitamin C, we read with great interest the report on the COVID A to Z Randomized Clinical Trial (COVID A to Z trial) which investigated the effects of 8 g/day vitamin C on the recovery from outpatient SARS-CoV-2 infection (9). However, we unfortunately found several methodological shortcomings in the trial. Here we describe our major concerns and statistical reanalysis of the findings.
  • Hemilä, Harri (1996)
    In 1971, Linus Pauling carried out a meta-analysis of four placebo-controlled trials and concluded that it was highly unlikely that the decrease in the "integrated morbidity of the common cold" in vitamin C groups was caused by chance alone (P < 0.00003). Studies carried out since then have consistently found that vitamin C (> or = 1 g/d) alleviates common cold symptoms, indicating that the vitamin does indeed have physiologic effects on colds. However, widespread conviction that the vitamin has no proven effects on the common cold still remains. Three of the most influential reviews drawing this conclusion are considered in the present article. Two of them are cited in the current edition of the RDA nutritional recommendations as evidence that vitamin C is ineffective against colds. In this article, these three reviews are shown to contain serious inaccuracies and shortcomings, making them unreliable sources on the topic. The second purpose is to suggest possible conceptual reasons for the persistent resistance to the notion that vitamin C might have effects on colds. Although placebo-controlled trials have shown that vitamin C does alleviate common cold symptoms, important questions still remain.
  • Hemilä, Harri (1996)
    A large number of placebo-controlled studies have shown that vitamin C supplementation alleviates the symptoms of the common cold, but widespread skepticism that vitamin C could have any significant effect remains. One of the most influential common cold studies, published in 1975, was carried out by Thomas Karlowski et al, at the National Institutes of Health. Their placebo consisted of lactose, which can easily be distinguished from ascorbic acid by taste. Karlowski et al, found a 17% decrease in the duration of cold episodes in the group administered vitamin C (6 g/day); however, they suggested that the decrease was entirely due to the placebo effect. In this article it will be shown that the placebo effect is not a valid explanation for the results of the Karlowski study, as it is inconsistent with their results. This is an important conclusion for two reasons. First, the placebo explanation becomes even more unreasonable as regards the reported benefits found in several other studies with valid placebo tablets. Second, as the results from the Karlowski study are not due to the placebo effect, their results can be used to assess the quantitative effects of vitamin C supplementation. The most important conclusions from Karlowski's study are that therapeutic vitamin C supplementation during a common cold episode appears to be as effective as regular supplementation, and that there appears to be linear dose dependency at least up to 6 g/day. These findings suggest that large therapeutic vitamin C doses might alleviate the symptoms of the common cold substantially.
  • Hemilä, Harri; Haukka, Jari; Alho, Marianne; Vahtera, Jussi; Kivimäki, Mika (2020)
    Objective To examine a commercially available zinc acetate lozenge for treating the common cold. Design Randomised, double-blinded, placebo-controlled trial. Setting Working population in Finland. Participants We included men and women aged >= 18 years who usually had >= 1 cold per winter. Exclusions were pregnancy, lactation, chronic runny nose or chronic cough. Intervention We randomised 253 participants to receive a package of lozenges to be taken if they caught the common cold. Of the 253 participants, 88 contracted the common cold and 87 were included in our primary analysis. Zinc acetate lozenges contained 13 mg elemental zinc and placebo lozenges contained sucrose octa-acetate to camouflage the taste of zinc. Instruction to use was six times per day for the maximum of 5 days. Primary outcome Rate of recovery from the common cold analysed by Cox regression. Results There was no difference in the recovery rate between zinc and placebo participants during the 10-day follow-up (rate ratio for zinc vs placebo=0.68, 95% CI 0.42 to 1.08; p=0.10). The recovery rate for the two groups was similar during the 5-day intervention, but for 2 days after the end of zinc/placebo use, the zinc participants recovered significantly slower compared with the placebo participants (p=0.003). In the zinc group, 37% did not report adverse effects, the corresponding proportion being 69% in the placebo group. Conclusions A commercially available zinc acetate lozenge was not effective in treating the common cold when instructed to be used for 5 days after the first symptoms. Taste has been a common problem in previous zinc lozenge trials, but a third of zinc participants did not complain of any adverse effects. More research is needed to evaluate the characteristics of zinc lozenges that may be clinically efficacious before zinc lozenges can be widely promoted for common cold treatment.
  • Hemila, Harri; Petrus, Edward J.; Fitzgerald, James T.; Prasad, Ananda (2016)
    AimsThe aim of this study was to determine whether the allergy status and other characteristics of common cold patients modify the effects of zinc acetate lozenges. MethodsWe had available individual patient data for three randomized placebo-controlled trials in which zinc acetate lozenges were administered to common cold patients. We used both one stage and two stage meta-analysis to estimate the effects of zinc lozenges. ResultsThe total number of common cold patients was 199, the majority being females. Eighty percent of them fell into the age range 20-50years. One third of the patients had allergies. The one stage meta-analysis gave an overall estimate of 2.73days (95% CI 1.8, 3.3days) shorter colds by zinc acetate lozenge usage. The two stage meta-analysis gave an estimate of 2.94days (95% CI 2.1, 3.8days) reduction in common cold duration. These estimates are to be compared with the 7day average duration of colds in the three trials. The effect of zinc lozenges was not modified by allergy status, smoking, baseline severity of the common cold, age, gender or ethnic group. ConclusionSince the effects of zinc acetate lozenges were consistent between the compared subgroups, the overall estimates for effect seemed applicable over a wide range of common cold patients. While the optimal composition of zinc lozenges and the best frequency of their administration should be further investigated, given the current evidence of efficacy, common cold patients may be encouraged to try zinc lozenges for treating their colds.
  • Hemilä, Harri; Fitzgerald, James T.; Petrus, Edward J.; Prasad, Ananda (2017)
    BACKGROUND: A previous meta-analysis of 3 zinc acetate lozenge trials estimated that colds were on average 40% shorter for the zinc groups. However, the duration of colds is a time outcome, and survival analysis may be a more informative approach. The objective of this individual patient data (IPD) meta-analysis was to estimate the effect of zinc acetate lozenges on the rate of recovery from colds. METHODS: We analyzed IPD for 3 randomized placebo-controlled trials in which 80-92 mg/day of elemental zinc were administered as zinc acetate lozenges to 199 common cold patients. We used mixed-effects Cox regression to estimate the effect of zinc. RESULTS: Patients administered zinc lozenges recovered faster by rate ratio 3.1 (95% confidence interval, 2.1-4.7). The effect was not modified by age, sex, race, allergy, smoking, or baseline common cold severity. On the 5th day, 70% of the zinc patients had recovered compared with 27% of the placebo patients. Accordingly, 2.6 times more patients were cured in the zinc group. The difference also corresponds to the number needed to treat of 2.3 on the 5th day. None of the studies observed serious adverse effects of zinc. CONCLUSIONS: The 3-fold increase in the rate of recovery from the common cold is a clinically important effect. The optimal formulation of zinc lozenges and an ideal frequency of their administration should be examined. Given the evidence of efficacy, common cold patients may be instructed to try zinc acetate lozenges within 24 hours of onset of symptoms.
  • Hemilä, Harri (2017)
    OBJECTIVE: To compare the efficacy of zinc acetate lozenges with zinc gluconate lozenges in common cold treatment and to examine the dose-dependency of the effect. DESIGN: Meta-analysis. SETTING: Placebo-controlled zinc lozenge trials, in which the zinc dose was > 75 mg/day. The pooled effect of zinc lozenges on common cold duration was calculated by using inverse-variance random-effects method. PARTICIPANTS: Seven randomised trials with 575 participants with naturally acquired common colds. MAIN OUTCOME MEASURE: Duration of the common cold. RESULTS: The mean common cold duration was 33% (95% CI 21% to 45%) shorter for the zinc groups of the seven included trials. Three trials that used lozenges composed of zinc acetate found that colds were shortened by 40% and four trials that used zinc gluconate by 28%. The difference between the two salts was not significant: 12 percentage points (95% CI: -12 to + 36). Five trials used zinc doses of 80-92 mg/day, common cold duration was reduced by 33%, and two trials used zinc doses of 192-207 mg/day and found an effect of 35%. The difference between the high-dose and low-dose zinc trials was not significant: 2 percentage points (95% CI: -29 to + 32). CONCLUSIONS: Properly composed zinc gluconate lozenges may be as effective as zinc acetate lozenges. There is no evidence that zinc doses over 100 mg/day might lead to greater efficacy in the treatment of the common cold. Common cold patients may be encouraged to try zinc lozenges for treating their colds. The optimal lozenge composition and dosage scheme need to be investigated further.