Influenza and asthma

The relationship between infections of the respiratory tract and exacerbations of pulmonary symptoms in individuals with asthma is well established on clinical grounds. Patients having an acute attack of asthma often give a history of a "cold" before the onset of the exacerbation. The identification rate of viruses during exacerbations of asthma (10-30%) is much higher than the viral identification rate generally found during asymptomatic periods in asthmatics (3%). The mechanisms whereby upper respiratory viruses might induce or contribute to attacks of asthma are currently unknown: epithelial damage, increased cytokines releasability, mouth breathing.... Influenza vaccination is recommended in patients with chronic pulmonary diseases. However, bronchial hyperreactivity has been reported after influenza vaccination in asthmatics. Reactions to these vaccines may be due to non-immunogenic impurities, which are not present in the more recently developed subunit vaccines. In spite of the lack of double-blind studies between subunit and killed influenza virus vaccines, and because of the potential bad prognosis of influenza infection on airway obstruction, influenza vaccination should be recommended in asthmatics with stable respiratory function but influenza vaccination rate remains low.     

Predictors of seasonal influenza vaccination in chronic asthma

Background

Guidelines advise annual influenza vaccination in chronic asthma. The aim of this study was to determine uptake of the influenza vaccine in a group of patients (n?=?146) with moderate to severe chronic asthma and establish the main predictors of vaccination.

Method

Patients attending a hospital asthma clinic were asked to complete a questionnaire in February 2012 (n?=?146). These same patients were contacted a year later via telephone (n?=?109 responded), and they were asked to complete the same questionnaire.

Results

Vaccination rate was 50.3% in winter 2011/12, and 57.8% in 2012/13. Using binary logistic regression, the predictors for vaccination in 2012 were patient advice (Odds ratio [OR] 15.37 p?=?0.001), female gender (OR 2.75, p?=?0.028), past side effects (OR 0.21, p?=?0.001) and comorbidity (OR 0.39, p?=?0.013). Stepwise regression resulted in age as predictor (T value?=?3.99, p?=?0.001). On analyzing the responses from the second questionnaire at one year after attendance to asthma clinic, predictors changed to compliance to medication (OR 9.52, p= 0.001) and previous exacerbations (OR 4.19, p?=?0.026). Out of the 56 patients vaccinated in 2011/12, 33 reported asthma exacerbations before 2012, and 29 reported asthma exacerbations after receiving the influenza vaccine. Out of the 46 unvaccinated patients in 2012, 27 had asthma exacerbations before 2012 and 19 patients had exacerbations in 2013. Patients vaccinated in 2011/12 needed 0.59 courses of steroid/patient/year, and 1.23 visits for nebulizer/patient/year while non-vaccinated patients needed 0.18 courses of steroids/patient/year (p?=?0.048), and 0.65 visits for nebulized/patient/year (p?=?0.012). Patients’ subjective statements broadly confirmed the predictors. 16/69 (23.1%) received the vaccine in winter 2012/13 despite reporting previous side effects.

Conclusions

Advice to patient, female gender and patients’ age predicted vaccination, while past side effects to the influenza vaccine, and presence of comorbidities predicted non vaccination. Symptomatic asthma patients are more likely to be vaccinated. One year after the first contact, treatment compliance and previous asthma exacerbations gained statistical significance as predictors of vaccination.

     

Evaluation of Respiratory Viral Pathogens in Acute Asthma Exacerbations during Childhood

Objective. Common upper respiratory tract viruses are the most frequent and important causes of asthma exacerbations in both children and adults. Prospective epidemiologic studies report that up to 80% of childhood exacerbations are associated with viral upper respiratory tract infections. Materials and methods. The study group consisted of 104 children with asthma aged 3–17 years who received treatment for asthma exacerbations in our clinic between September 2009 and 2010. Nasopharyngeal and nasal swabs were obtained from all patients during an acute attack, and from the control group (31 subjects). These specimens were investigated for the presence of viral respiratory pathogens using a real-time multiplex PCR method. The patients were compared for the presence of respiratory pathogens and factors related to the severity of the asthma exacerbation. Results. A pathogenic respiratory virus was detected in 53.8% of patients in the acute exacerbation group. The most commonly encountered viral agent was Rhinovirus (35.6%). Patients who had an acute exacerbation with or without a detectable viral pathogen were compared according to the severity of the exacerbation, the need for systemic steroids, and hospitalization rates. No statistically significant difference was found. Conclusion. Although viral upper respiratory tract infections are the most common cause of asthma exacerbations, the severity level of the exacerbation seems to be independent of whether a respiratory virus has been detected.     

Influenza vaccination in subjects with alpha1-antitrypsin deficiency

BACKGROUND: Influenza vaccination is recommended for all subjects with COPD, including alpha(1)-antitrypsin deficiency (AATD), but immunization practices are below US national goals. Influenza vaccination practices and their relation to respiratory outcomes in AATD are unknown. METHODS: Nine hundred thirty-nine subjects with AATD were followed up prospectively by monthly telephone interviews during the 2003 to 2004 influenza season. Vaccination status, exacerbation rates, and health-care utilization were documented. Residence zip codes were used to group subjects as living in high or low influenza-like illness (ILI) prevalence areas according to published Centers for Disease Control and Prevention data for the same influenza season. RESULTS: Overall, 81.6% of subjects received influenza vaccination, with no differences noted by gender, age (median age 52 years), Global Initiative for Chronic Obstructive Lung Disease stage, or ILI prevalence area. No significant differences were noted in the overall acute exacerbation rates using two different criteria between vaccinated and unvaccinated subjects (mean, 1.5 +/- 1 exacerbations per subject). Similarly, no differences were noted in either the severity of exacerbations or the monthly exacerbation rates between the two groups. Unvaccinated subjects had more unscheduled physician visits than vaccinated subjects, but there were no significant differences in scheduled visits, emergency department visits, or hospitalizations between the two groups. Older age (> 60 years) or residence in a high ILI prevalence area had no effect on outcomes. CONCLUSION: Subjects with AATD in the United States receive adequate influenza vaccination regardless of age. However, we did not observe a significant impact of the vaccination on disease exacerbations and other respiratory outcomes during the 2003 to 2004 influenza season.     

Role of viruses in exacerbations of chronic obstructive pulmonary disease

Exacerbations of chronic obstructive pulmonary disease (COPD) are a major cause of morbidity and mortality and hospital admission. Respiratory viral infections, especially rhinoviruses, are a major cause of COPD exacerbations, with upper respiratory tract infections being associated with over 50% of COPD exacerbations. The presence of an upper respiratory tract infection leads to a more severe exacerbation and a longer symptom recovery time at exacerbation. Respiratory viral infections occurring during COPD exacerbations are more likely to lead to hospitalization. Sputum inflammatory markers were found to be higher in those patients with symptoms of a common cold or where rhinovirus was detected at exacerbation, thus suggesting that viral infections lead to greater airway inflammation and thus more severe exacerbations. COPD exacerbations are associated also with systemic inflammatory effects with increases in markers such as plasma fibrinogen and interleukin-6. Respiratory viruses have also been detected when the patients are stable, and this suggests that chronic viral infection may occur. Strategies to prevent viral infection will have a significant effect on the morbidity of COPD and will improve quality of life.     

The similarities and differences of epidemic cycles of chronic obstructive pulmonary disease and asthma exacerbations

The majority of chronic obstructive pulmonary disease (COPD) and asthma exacerbations in both children and adults are associated with respiratory viral infections and are cyclic in nature. Some variation in these cycles is associated with the timing of the appearance of respiratory viruses, particularly influenza and respiratory syncytial virus. Much more, however, is associated with signal events that are of either fixed or predictable timing. In children, asthma exacerbations reach epidemic levels following school return after the summer vacation and these are predominantly associated with rhinovirus infections. Although younger adults experience a rise in asthma exacerbations at this time, these are secondary to the epidemic in children. Older adults with either COPD or asthma experience only a slightly elevated risk of exacerbations after school return, and hospital presentations for pneumonia in any age group show only marginal increases at that time. Exacerbations of both COPD and adult asthma, with increasing risk with age, are at their highest average annual levels during the Christmas period. This effect appears to be independent of the timing of above average levels of influenza, RSV, parainfluenza, or adenovirus detections; however, hospitalization for respiratory tract infections in all age groups reaches high levels at the same time. Both the post-summer vacation asthma epidemic and the Christmas epidemic of COPD, asthma, and pneumonia are synchronous with the timing of signal events, the day of school return for the former and Christmas Day for the latter, and have been for several years. The agents responsible for the Christmas epidemic of respiratory diseases have not yet been identified. The differences between age and disease exacerbation patterns after school return and at Christmas suggest that either different agents are involved or that the response to a common agent is different between the two signal events.     

Influenza Vaccination in Adults with Asthma: Safety of an Inactivated Trivalent Influenza Vaccine

Despite recommendations in most countries for giving inactivated influenza vaccine to people with asthma, only a minority currently receive it. One reason for low vaccine coverage has been concern that vaccination may induce exacerbations of asthma. In this randomized trial, 291 patients between 18 and 65 years of age received either an inactivated influenza vaccine followed 14 days later by a saline placebo or placebo followed by the vaccine. Each patient received 1 dose of vaccine and 1 dose of placebo. The percentage of patients reporting at least one asthma exacerbation within 14 days after injection was similar following vaccine or placebo (28.3% and 25.5%, respectively). The combined exacerbation rate during the first 14-day interval was higher (31.5%) than that during the second 14-day interval (22.4%, P = 0.0135), indicating that the occurrence of exacerbations was not likely to be related to the sequence of injections. The percentages of individuals with solicited systemic symptoms were 56.6% and 44.8% after vaccine or placebo injection, respectively. We conclude that influenza vaccination did not increase the incidence of asthma exacerbations compared to placebo in this study and the vaccine was well tolerated. The results thus support annual influenza vaccination in patients with asthma.     

Influenza Vaccination in Adults with Asthma: Safety of an Inactivated Trivalent Influenza Vaccine

Despite recommendations in most countries for giving inactivated influenza vaccine to people with asthma, only a minority currently receive it. One reason for low vaccine coverage has been concern that vaccination may induce exacerbations of asthma. In this randomized trial, 291 patients between 18 and 65 years of age received either an inactivated influenza vaccine followed 14 days later by a saline placebo or placebo followed by the vaccine. Each patient received 1 dose of vaccine and 1 dose of placebo. The percentage of patients reporting at least one asthma exacerbation within 14 days after injection was similar following vaccine or placebo (28.3% and 25.5%, respectively). The combined exacerbation rate during the first 14-day interval was higher (31.5%) than that during the second 14-day interval (22.4%, P = 0.0135), indicating that the occurrence of exacerbations was not likely to be related to the sequence of injections. The percentages of individuals with solicited systemic symptoms were 56.6% and 44.8% after vaccine or placebo injection, respectively. We conclude that influenza vaccination did not increase the incidence of asthma exacerbations compared to placebo in this study and the vaccine was well tolerated. The results thus support annual influenza vaccination in patients with asthma.     

The epidemiology of COPD and asthma exacerbations in a general hospital

This retrospective study identified the clinical and epidemiological characteristics of patients coming to the emergency room of our hospital with exacerbated asthma or chronic obstructive pulmonary disease (COPD) in 1993 and 1994. We followed a previously established protocol to review the case histories of patients from both years. The 1,592 exacerbations we identified in 1,209 asthmatics accounted for 0.9% of all emergency visits, with a mean of 2.2 1.6 (0-9) visits daily. The 2,106 exacerbations of COPD in 1,208 patients accounted for 1.2% of all emergencies, with a mean 2.9 (1-12) visits per day. The mean age was 51.2 (14-93) years for asthmatics and 70.3 (29-96) years for COPD patients. Of asthmatics, 69.8% were women and 30.1% were men, whereas 91.4% of COPD patients were men. The readmission rate was 3.4% for asthmatics and 4.8% for COPD patients. The hospitalization rate was 26.7% for asthmatics and 49.4% for COPD exacerbation patients. The hospital saw 22.6% of asthma exacerbations between midnight and 8 a.m. and 41.6% of COPD exacerbations during the same time frame. For both diseases, more emergencies occurred in winter. Correlation between asthma and COPD and declared influenza cases in the community were r = 0.63 (p < 0.001) for asthma and r = 0.83 (p < 0.0001) for COPD. Our findings underline the considerable emergency care burden generated by exacerbations of obstructive airway diseases and suggest that community acquired respiratory infections are usually the underlying cause.     

Protective effects of influenza A (H1N1) pandemic 2009 vaccination against the onset of influenza-like illness and asthma exacerbation in Japanese children

Background: Vaccination against influenza A(H1N1)pdm09 in Japan started in October 2009. Children with asthma are considered as a high-risk group and are recommended to preferentially receive the vaccine. Objective: To identify the clinical effects of vaccination in Japanese children with and without asthma. Methods: We conducted a cross-sectional, questionnaire-based survey to compare vaccination rates, vaccine effectiveness against physician-diagnosed influenza A infection (PDIA), and consecutive asthma exacerbations between children with and without asthma. Results: Of the 460 children included in this study, those with asthma had higher vaccination rates (46.5%, 67/144) than those without asthma (30.4%, 96/316). Influenza A infections were diagnosed in 28 of 163 vaccinated children (17.2%) compared to 164 of 297 unvaccinated children (55.2%, p?Conclusions: The administration of an inactivated, split-virus, non-adjuvanted monovalent A(H1N1)pdm09 vaccine during the pandemic period reduced the number of physician-diagnosed influenza A infections and asthma exacerbations in children with asthma. Therefore, we strongly recommend that high-risk children with a history of asthma receive vaccines during pandemics.     

The role of viral respiratory infections in the pathogenesis and exacerbation of asthma

Respiratory viral infections are implicated in both the pathogenesis and exacerbation of asthma. Infections with respiratory syncytial virus and parainfluenza virus are the major cause of wheezing-related respiratory infections early in life. Infections in early childhood affect the immune system and modify the risk for subsequent development of allergies and asthma. Later in life, rhinovirus and influenza are implicated frequently in the exacerbation of asthma. The management of respiratory viral infections includes adequate prophylaxis and treatment of acute infections. Insights into the mechanism of viral respiratory tract infections will provide therapeutic targets for treatment and possibly the prevention of virus-induced asthma.     

Immunomodulating effect of influenza vaccination in the elderly differing in health status

The aim of this study was to analyse whether split influenza vaccine may elicit NK cytotoxic response in the vaccinated elderly people and whether this effect may be maintained over few weeks after vaccination. It was also worth investigating the relation between NK activity in the vaccinated and specific immune protection against influenza and non-specific against other infections. Two groups of volunteers were vaccinated with trivalent split viron influenza vaccine in two consecutive seasons (1999/2000; 2000/2001). The elderly group consisted of 142 people (65-92 years old) in the first season and 110 in the second; while the young (16-44 years old) of 98 and 67 people, respectively. An analysis of NK cytotoxic activity had been done before vaccination, two days, one month and fifth months thereafter. The results revealed that vaccination with the influenza vaccine had an augmenting effect on NK activity, in all groups examined, in both epidemic seasons, visible at two days and 1 month after the vaccination. In the elderly high pre- and post-vaccination NK activity was related to higher titers of anti-hemagglutinin, better health status and lower incidence of all cause respiratory tract infections. At the second vaccination, most of the elderly with chronic medical conditions and high NK activity, who did not attain the protective level of anti-hemagglutinins in the first season, converted into the protected. High pre- and post-vaccination NK activity predisposes elderly people to the protective humoral anti-hemagglutinin response and gives better protection from respiratory tract infections.     

What is the role of virus vaccination in patients with asthma?

It is estimated that viruses play a role in 30% to 80% of asthma exacerbations. Thus, virus vaccination in patients with asthma could play an important role in preventing asthma exacerbations and other complications. Influenza is the only agent for which a routine vaccine is currently available. This article discusses whether influenza vaccination in patients with asthma, based on the available evidence, is justified. Cost-effectiveness of (influenza) vaccination for patients with asthma is questionable. For the other major viruses involved, the present state of affairs is described. Although progress is being made, a vaccine may be available in the near future only for respiratory syncytial virus (RSV). Meanwhile, clinicians and patients should aim for an optimal treatment with the currently available asthma medication.     

Two cases of asthmatic exacerbation caused by parainfluenza virus 3 infection]

Although viral respiratory tract infections are considered to be the most frequent causes of asthmatic exacerbation, respiratory viruses can rarely be detected in the adult population. We describe 2 cases, in a 43-yr-old man with severe atopic asthma and in a 69-yr-old man with moderate non-atopic asthma. After the onset of nasal discharge, sore throat and fever, the asthma had become exacerbated in both cases during the summer of 2002. In both cases, parainfluenza virus (PIV) 3 viral RNA could be detected from oral gargling by RT-PCR, and the serum viral antibody titer against PIV 3 increased significantly. These cases were therefore diagnosed as undergoing asthmatic exacerbation caused by PIV 3 infection and were successfully treated with systemic steroids. During summer, 2002, in our outpatient clinic, PIV 3 infection was demonstrated in approximately half of the asthmatic exacerbations associated with upper respiratory symptoms, including the present cases. Collectively, PIV 3 seems to represent an important viral cause of asthma exacerbation in summer.     

Identification of strains on recurrent Haemophilus influenzae infections in patients with chronic respiratory tract infections]

Nontypable Haemophilus influenzae is one of the most important pathogenic bacteria in respiratory tract infections. H. influenzae is most frequently associated with recurrent infections in chronic respiratory tract infections (CRTIs). It is known that H. influenzae often reemerges after the antibiotic treatment has been stopped. We analyzed serotype, biotype, and the OMP patterns of H. influenzae isolates from sputum of CRTIs patients to determine whether an exacerbation is caused by an identical H. influenzae strain, or by a new H. influenzae strain. One hundred eighty nine strains of H. influenzae were obtained from 124 exacerbation from 24 patients. The first and second isolates were identical in 23 out of 33 exacerbations (< or = 15-days interval between each exacerbation) and also in 22 out of 34 exacerbations (15 < days but < or = 30-days interval between each exacerbation). This is called early recurrence. In contrast, the first and second isolates were different in 28 out of 34 exacerbations (> 30-days interval between each exacerbation). This is called late recurrence. These results suggest that early recurrence and late recurrence of recurrent H. influenzae infections occur in a different mechanism.     

Childhood respiratory infections and hospital admissions for COPD

BACKGROUND: Chronic Obstructive Pulmonary Disease (COPD) exacerbations are associated with viral infections. We wished to determine if respiratory viral infection of children in the community was associated with hospital admissions of patients with exacerbations of COPD. METHODS: We collected data over a 45-month period from the Northern Ireland Regional Virus Laboratory and from a general hospital in the same locality. We studied the relationship between upper respiratory infections in children and COPD admissions. We also examined the role of school holidays. RESULTS: Correlations were seen between the frequency of all viral infections in children and the number of adult COPD hospitalizations (P<0.005). Subgroup analysis showed distinct relationships with epidemics of; influenza A (P<0.001), influenza B (P<0.05), adenovirus (P=0.05), respiratory syncytial virus (P<0.005) and hospital admissions of patients with COPD. There were significantly fewer COPD admissions in the week after the start of a school holiday period (P<0.05). CONCLUSIONS: When children are hospitalized with viral respiratory infection there is an associated rise in adult COPD admissions. This suggests exacerbations of COPD are associated with epidemics of respiratory viruses. When children are on school holidays there is a reduction in COPD admissions in the community. This provides further support for respiratory viruses in the pathogenesis of COPD exacerbations.     

Rhinoviruses infect the lower airways

Rhinoviruses are the major cause of the common cold and a trigger of acute asthma exacerbations. Whether these exacerbations result from direct infection of the lower airway or from indirect mechanisms consequent on infection of the upper airway alone is currently unknown. Lower respiratory infection was investigated in vitro by exposing primary human bronchial epithelial cells to rhinoviruses and in vivo after experimental upper respiratory infection of human volunteers. Bronchial infection was confirmed by both approaches. Furthermore, rhinoviruses induced production of interleukin-6, -8, and -16 and RANTES and were cytotoxic to cultured respiratory epithelium. This evidence strongly supports a direct lower respiratory epithelial reaction as the initial event in the induction of rhinovirus-mediated asthma exacerbations. The frequency of infection and the nature of the inflammatory response observed are similar to those of the upper respiratory tract, suggesting that rhinovirus infections may be one of the most important causes of lower in addition to upper respiratory disease.     

Effectiveness of pneumococcal polysaccharide vaccine in older patients with chronic respiratory diseases]

To evaluate effectiveness of pneumococcal polysaccharide vaccine, we recommended 1378 outpatients aged over 60 with chronic respiratory diseases to be vaccinated from August to October 2002, and 647 patients were vaccinated from August to November 2002. In the 1229 patients without respiratory failure, the incidence of antimicrobial treatment for bacterial respiratory infections in 547 vaccinated patients significantly decreased from 7.9% in the 2001/02 winter season to 5.7% in the 2002/03 winter season, although that in the 682 unvaccinated patients increased from 3.8% to 5.7%. The incidence of antimicrobial treatment for bacterial respiratory infections in 229 vaccinated patients with pneumococcal and influenza vaccines together significantly decreased from 10.5% in the 2001/02 winter season to 5.2% in 2002/03 winter season although that in 110 subjects vaccinated with influenza vaccine only increased from 2.7% to 7.2%. These findings suggest the effectiveness of the pneumococcal polysaccharide vaccine for the prevention of bacterial respiratory infections and the additive effectiveness of pneumococcal and influenza vaccines together.