Controlled study of respiratory viruses and wheezing

Efficacy of vitamin C for the prevention and treatment of upper respiratory tract infection. A meta-analysis in children

PURPOSE

Upper respiratory tract infection (URTI) is a common infection in children, generally caused by viral respiratory infection. Vitamin C is currently proposed as prophylaxis for URTI. The purpose of this study was to assess the effectiveness of vitamin C administration in children for the prevention and reduced duration of URTI through a systematic literature review.

METHODS

Review of the literature conducted between October 2017 and January 2018 in the main medical databases (CENTRAL, Medline and Embase) and by a gray literature approach. The selection criteria were: double-blind randomized controlled trials (RCTs) comparing vitamin C use to placebo in children aged 3 months to 18 years without chronic infection. Efficacy was assessed in terms of incidence, duration and severity of symptoms of URTI. A meta-analysis was conducted where possible.

RESULTS

Eight RCTs, including 3135 children aged 3 months to 18 years, were selected. Quantitative analysis showed no difference between vitamin C administration and placebo (odds ratio = 0.75, 95% CI [0.54-1.03], p = 0.07, I² = 74%). Vitamin C administration was found to decrease the duration of URTI by 1.6 days (standardized mean differences = -0.30 [-0.53; -0.08], p = 0.009, I² = 70%). Children under 6 years of age benefit from more effective vitamin C supplementation associated with echinacea. No serious adverse events were reported.

CONCLUSIONS

Although no preventive effects were found, vitamin C intake reduced the duration of URTI. Considering the frequency of URTI, the inappropriate prescription of antibiotics, and the safe nature of vitamin C, its supplementation is justified, especially in children under 6 years of age and those who present a high frequency of URTI. There is a sound rationale for further trials with greater statistical power among children of this age.

HPV, KRAS mutations, alcohol consumption and tobacco smoking effects on esophageal squamous-cell carcinoma carcinogenesis

Esophageal squamous-cell carcinoma (ESCC) is an invasive neoplastic disease generally associated with poor survival rates. The incidence of ESCC is characterized by marked geographic variation, with highest rates noted in developing Southeastern African, Central and Eastern Asian countries. In the developed Western European and North American regions where there is a low disease incidence, heavy alcohol and cigarette consumption constitute major risk factors. The toxic effects of both these risk factors cause chronic irritation and inflammation of the esophageal mucosa, while at the cellular level they further confer mutagenic effects by the activation of oncogenes (e.g., RAS mutations), inhibition of tumor-suppressor genes, and profound DNA damage. Viral infections, particularly with human papillomavirus, may activate specific antiapoptotic, proliferative and malignant cellular responses that may be intensified in combination with the effects of alcohol and tobacco. In countries with a high ESCC incidence, low socioeconomic status and an inadequate diet of poorly preserved food are combined with basic nutritional deficiencies and inadequate medical treatment. These conditions are favorable to the above-mentioned risk factors implicated in ESCC development, which may be present and/or habitually used in certain populations. New perspectives in epidemiological studies of ESCC development and its risk factors allow genome-wide research involving specific environments and habits. Such research should consist of adequately large and representative samples, should use newly designed informative genetic markers, and apply genomic variation analysis of the functional transcripts involved in malignant cell cycle regulation and neoplastic transformation in the multi-step process of ESCC carcinogenesis.

Intranasal delivery of whole influenza vaccine prevents subsequent allergen-induced sensitization and airway hyper-reactivity in mice

BACKGROUND

Infection with influenza virus has been associated with seemingly opposing effects on the development of asthma. However, there are no data about the effects of mucosal vaccination with inactivated influenza on the inception of allergic asthma.

OBJECTIVE

To assess the immunological effects of inhaled inactivated influenza vaccine, using two different types of flu vaccines, on the inception of allergic sensitization and allergen-mediated airway disease in a mouse model.

METHODS

BALB/c mice were intranasally or intratracheally vaccinated with whole or split influenza virus vaccine (days -1 or -1, 27) before systemic sensitization with ovalbumin (OVA) (days 1, 14) and repeated airway allergen challenges (days 28-30). Allergen sensitization (IgE serum levels), airway inflammation (differential cells in bronchoalveolar lavage fluid) and airway hyper-reactivity (AHR) (in vivo lung function) were analysed.

RESULTS

The intranasal instillation of whole influenza vaccine before allergen sensitization significantly reduced the serum levels of total and OVA-specific IgE as well as allergen-induced AHR. Prevention was due to an allergen-specific shift from a predominant T helper (Th)2- towards a Th1-immune response. Application of split influenza vaccine did not show the same preventive effect.

CONCLUSION

Intranasal administration of inactivated whole influenza vaccine reduced subsequent allergen sensitization and prevented allergen-induced AHR. Our results show that the composition of the influenza vaccine has a major influence on subsequent development of allergen-induced sensitization and AHR, and suggest that mucosal inactivated whole influenza vaccination may represent a step towards the development of a preventive strategy for atopic asthma.

Effectiveness of influenza vaccine for the prevention of asthma exacerbations

BACKGROUND

There is a lack of clinical evidence that annual vaccination against influenza prevents asthma exacerbations in children.

METHODS

Retrospective cohort study of 800 children with asthma, where one half did, and the other half did not receive the influenza vaccine. The two groups were compared with respect to clinic visits, emergency department (ED) visits, and hospitalisations for asthma. In multivariable analyses, adjustment was made for baseline asthma severity, prior utilisation of health services, receipt of vaccine in the previous year, and demographic variables.

RESULTS

After adjusting for other variables, the vaccine group had a significantly increased risk of asthma related clinic visits and ED visits (odds ratios 3.4 and 1.9, respectively).

CONCLUSION

This study failed to provide evidence that the influenza vaccine prevents paediatric asthma exacerbations.

Noninvasive positive-pressure ventilation in children with lower airway obstruction

STUDY OBJECTIVES

Mechanical ventilation of patients with severe lower airway obstruction presents significant risks; therefore, avoiding the intubation in these patients has been a principal goal of clinical management. Noninvasive positive-pressure ventilation has been shown to be effective in treating adults with chronic obstructive pulmonary disease, but its use has not been studied prospectively in children with acute obstructive lower airways disease. The objective of this study was to determine whether noninvasive mask ventilation improved respiratory function in children with asthma and other obstructive lower airways diseases.

STUDY DESIGN

A prospective, randomized, crossover study.

PATIENTS

A total of 20 children admitted to the pediatric intensive care unit with acute lower airway obstruction.

METHODS

Children were randomized to receive either 2 hrs of noninvasive ventilation followed by crossover to 2 hrs of standard therapy or 2 hrs of standard therapy followed by 2 hrs of noninvasive ventilation.

RESULTS

Using a Clinical Asthma Score, we found that noninvasive ventilation decreased signs of work of breathing such as respiratory rate, accessory muscle use, and dyspnea as compared with standard therapy. There was no serious morbidity associated with noninvasive ventilation.

CONCLUSIONS

We conclude that noninvasive ventilation can be an effective treatment for children with acute lower airway obstruction.

Three day versus five day treatment with amoxicillin for non-severe pneumonia in young children: a multicentre randomised controlled trial

OBJECTIVE

To assess the efficacy of three days versus five days of treatment with oral amoxicillin for curing non-severe pneumonia in children.

DESIGN

Randomised, double blind, placebo controlled multicentre trial.

SETTING

Outpatient departments of seven referral hospitals in India.

PARTICIPANTS

2188 children aged 2-59 months, 1095 given three days of treatment and 1093 given five days.

INTERVENTION

Oral amoxicillin 31-54 mg/kg/day in three divided doses.

MAIN OUTCOME MEASURES

Treatment failure: defined as development of chest indrawing, convulsions, drowsiness, or inability to drink at any time; respiratory rate above age specific cut points on day 3 or later; or oxygen saturation by pulse oximetry < 90% on day 3.

RESULTS

The clinical cure rates with three days and five days of treatment were 89.5% and 89.9%, respectively (absolute difference 0.4 (95% confidence interval--2.1 to 3.0)). Adherence to treatment regimen was 94% and 85% for three day and five day treatments, respectively. Loss to follow up was 5.4% by day 5. There were no deaths, 41 hospitalisations, and 36 minor adverse reactions. There were 225 (10.3%) clinical failures and 106 (5.3%) relapses, and rates were similar in both treatments. At enrollment, 513 (23.4%) children tested positive for respiratory syncytial virus, and Streptococcus pneumoniae and Haemophilus influenzae were isolated from the nasopharynx in 878 (40.4%) and 496 (22.8%) children, respectively. Clinical failure was associated with isolation of respiratory syncytial virus (adjusted odds ratio 1.95 (95% confidence interval 1.0 to 3.8)), excess respiratory rate of > 10 breaths/minute (2.89 (1.83 to 4.55)), and non-adherence with treatment at day 5 (11.57 (7.4 to 18.0)).

CONCLUSIONS

Treatment with oral amoxicillin for three days was as effective as for five days in children with non-severe pneumonia.