Is there a role for influenza vaccination in cystic fibrosis?

Update on advances in cystic fibrosis towards a cure and implications for primary care clinicians

During the past quarter century, the diagnosis and treatment of cystic fibrosis (CF) have been transformed by molecular sciences that initiated a new era with discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The knowledge gained from that breakthrough has had dramatic clinical impact. Although once a diagnostic dilemma with long delays, preventable deaths, and irreversible pathology, CF can now be routinely diagnosed shortly after birth through newborn screening programs. This strategy of pre-symptomatic identification has eliminated the common diagnostic "odyssey" that was a failure of the healthcare delivery system causing psychologically traumatic experiences for parents. Therapeutic advances of many kinds have culminated in CFTR modulator treatment that can reduce the effects of or even correct the molecular defect in the chloride channel -the basic cause of CF. This astonishing advance has transformed CF care as described fully herein. Despite this impressive progress, there are challenges and controversies in the delivery of care. Issues include how best to achieve high sensitivity newborn screening with acceptable specificity; what course of action is appropriate for children who are identified through the unavoidable incidental findings of screening tests (CFSPID/CRMS cases and heterozygote carriers); how best to ensure genetic counseling; when to initiate the very expensive but life-saving CFTR modulator drugs; how to identify new CFTR modulator drugs for patients with non-responsive CFTR variants; how to adjust other therapeutic modalities; and how to best partner with primary care clinicians. Progress always brings new challenges, and this has been evident worldwide for CF. Consequently, this article summarizes the major advances of recent years along with controversies and describes their implications with an international perspective.

A bird eye view on cystic fibrosis: An underestimated multifaceted chronic disorder

Cystic fibrosis (CF) is an autosomal recessive disease which involves the mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. CF involves in the inflammatory processes and is considered as a multisystem disorder that is not confined to lungs, but it also affects other vital organs that leads to numerous co-morbidities. The respiratory disorder in the CF results in mortality and morbidity which is characterized by series of serious events involving mucus hypersecretion, microbial infections, airways obstruction, inflammation, destruction of epithelium, tissue remodeling and terminal lung diseases. Mucins are the high molecular weight glycoproteins important for the viscoelastic properties of the mucus, play a significant role in the disease mechanisms. Determining the functional association between the CFTR and mucins might help to identify the putative target for specific therapeutic approach. In fact, furin enzyme which helps in the entry of novel COVID-19 virus into the cell, is upregulated in CF and this can also serve as a potential target for CF treatment. Moreover, the use of nano-formulations for CF treatment is an area of research being widely studied as they have also demonstrated promising outcomes. The in-depth knowledge of non-coding RNAs like miRNAs and lncRNAs and their functional association with CFTR gene expression and mutation can provide a different range of opportunity to identify the promising therapeutic approaches for CF.

Pulmonary complications of influenza infection: a targeted narrative review

Severe influenza infection represents a leading cause of global morbidity and mortality. Several clinical syndromes that involve a number of organs may be associated with Influenza infection. However, lower respiratory complications remain the most common and serious sequel of influenza infection. These include influenza pneumonia, superinfection with bacteria and fungi, exacerbation of underlying lung disease and ARDS. This review analyzes the available literature on the epidemiology and clinical considerations of these conditions. It also provides an overview of the effects of type of influenza, antiviral therapy, vaccination and other therapies on the outcome of these complications.

Coverage and predictors of influenza vaccination in patients with cystic fibrosis in a campaign with a mobile phone text messaging intervention

Annual influenza vaccination is considered the best protection against influenza infection. We analyzed the influenza vaccine coverage (IVC) in cystic fibrosis (CF) patients and evaluated the factors associated with the IVC, including the effect of text-message/SMS reminders.

We performed a cross-sectional study in the Community of Madrid (Spain) in 2015. The target population was people with CF older than 6 months of age at the beginning of the flu vaccination campaign. The IVC was calculated according to the study variables.

A total of 445 CF patients were analyzed. In 2015, IVC reached 67.9% and was higher in children and women. The main factor associated with flu vaccination was having been vaccinated in the previous campaign (aOR 14.36; IC95%: 8.48–24.32).

The probability of being vaccinated after receiving the SMS was more than twice than for those who did not receive it, although no statistical significance was reached.

In conclusion the IVC of patients with CF is high, but it still has room for improvement. SMS reminders sent to CF patients might improve influenza vaccine uptake.

Adverse events following live-attenuated intranasal influenza vaccination of children with cystic fibrosis: Results from two influenza seasons

BACKGROUND

Despite the approved use of live-attenuated intranasal influenza vaccine (LAIV) for seasonal immunization of patients with cystic fibrosis (CF), many questions remain unanswered regarding the timing, duration, and types of adverse events that occur following administration of this vaccine.

METHODS

In 2012 and 2013, 264 LAIV doses were administered to 198 patients aged 2-19 with CF. Vaccinees were followed prospectively for 55 days after vaccination (day 0) and information on adverse events was collected. Bayesian change-point analysis was used to identify the risk period following LAIV during which participants had a higher risk of reporting adverse events. Multivariable zero-inflated Poisson regression models were then used to estimate the adjusted incidence rate ratio (aIRR) and 95% credible interval (CrI) of reporting each adverse event in the risk period versus the control period.

RESULTS

There was a higher risk of reporting serious adverse events (SAEs) (aIRR 1.45, 95% CrI (0.29, 5.17)) and solicited symptoms during days 0-6 of follow-up compared to control period days 7-55. However, most SAEs were not causally related to LAIV and the solicited symptom episodes were brief, usually lasting 1-2 days. There was no increased risk of antibiotic prescriptions for respiratory conditions in the risk vs. control periods (aIRR 0.48, 95% CrI (0.23, 0.91)).

CONCLUSIONS

Adverse events were most common 0-6 days after LAIV administration but were generally benign and self-limiting. Pulmonary exacerbations did not increase in frequency.

Cystic Fibrosis Pulmonary Exacerbations Attributable to Respiratory Syncytial Virus and Influenza: A Population-Based Study

BACKGROUND.

Characterization of the role of respiratory viral pathogens on cystic fibrosis (CF) pulmonary disease is needed. We aimed to determine the association of influenza and respiratory syncytial virus (RSV) activity with risk of pulmonary exacerbation (PEx) in persons with CF in the United States.

METHODS.

We conducted a cohort study from January 2003 to March 2009 using the CF Foundation Patient Registry merged with Centers for Disease Control and Prevention respiratory virus surveillance data. The primary goal was to determine the association between regional influenza or RSV detections with risk of PEx requiring intravenous antibiotics or hospitalization. We analyzed outcomes by geographic region and week of event using multivariable regression models adjusted for demographic and clinical predictors of PEx stratified for children (<18 years) and adults (≥18 years) to calculate relative risks (RRs) of PEx.

RESULTS.

There were 21022 individuals (52% male) in the CF patient cohort in 2003 comprised of 12702 children and 8320 adults. The overall incidence rate of PEx was 521.9 per 10000 person-months. In children, a 10% increase in the proportion of surveillance tests positive for influenza or RSV was significantly associated with increased PEx risk (RR, 1.02; 95% confidence interval [CI], 1.01-1.03) and (RR, 1.05; 95% CI, 1.02-1.07), respectively. In adults, surveillance tests positive for influenza (RR, 1.02; 95% CI, 1.01-1.02), but not RSV (RR, 0.99; 95% CI, .98-1.01), had a significant association with PEx risk.

CONCLUSIONS.

Our large CF population-based cohort demonstrated a significant association between PEx risk and influenza activity in children and adults and with RSV activity in children.

Viruses in cystic fibrosis patients' airways

Although bacteria have historically been considered to play a major role in cystic fibrosis (CF) airway damage, a strong impact of respiratory viral infections (RVI) is also now recognized. Emerging evidence confirms that respiratory viruses are associated with deterioration of pulmonary function and exacerbation and facilitation of bacterial colonization in CF patients. The aim of this review is to provide an overview of the current knowledge on respiratory viruses in CF airways, to discuss the resulting inflammation and RVI response, to determine how to detect the viruses, and to assess their clinical consequences, prevalence, and interactions with bacteria. The most predominant are Rhinoviruses (RVs), significantly associated with CF exacerbation. Molecular techniques, and especially multiplex PCR, help to diagnose viral infections, and the coming rise of metagenomics will extend knowledge of viral populations in the complex ecosystem of CF airways. Prophylaxis and vaccination are currently available only for Respiratory syncytial and Influenza virus (IV), but antiviral molecules are being tested to improve CF patients' care. All the points raised in this review highlight the importance of taking account of RVIs and their potential impact on the CF airway ecosystem.

The diagnosis and management of respiratory viral infections in cystic fibrosis

INTRODUCTION

Respiratory viruses, such as those that cause influenza and the common cold, are a regular feature of life for the entire human population. Among people with CF, these viruses are associated with prolonged respiratory illness and show a clear association with pulmonary exacerbations which in turn are associated with lung function decline and risk of death. Human rhinovirus is the most commonly encountered respiratory viral pathogen in CF although adenovirus, bocavirus, coronavirus, influenza, parainfluenza, metapneumovirus and respiratory syncytial virus are all also responsible for infections in this population. Areas covered: This article reviews the epidemiology, clinical impact and therapeutic options for respiratory virus infection in both children and adults with CF. Expert commentary: The management of CF to date has largely focused on airway clearance strategies, nutritional support and aggressive antibacterial therapy. We highlight the significant role that respiratory viruses play in CF lung disease and argue that these pathogens represent an under-exploited target in the battle to control patients' symptoms and disease progression.

Neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis

BACKGROUND

Cystic fibrosis is the most common, life-threatening, recessively inherited disease of Caucasian populations. It is a multisystem disorder caused by a mutation in the gene encoding the cystic fibrosis transmembrane conductance regulator protein which is important in producing sweat, digestive juices and mucus.The impaired or absent function of this protein results in the production of viscous mucus within the lungs and an environment that is susceptible to chronic airway obstruction and pulmonary colonization by a range of pathogenic bacteria. Morbidity and mortality of cystic fibrosis is related to chronic pulmonary sepsis and its complications by these bacteria.Influenza can worsen the course of the disease in cystic fibrosis by increasing the risk of pneumonia and secondary respiratory complications. Antiviral agents form an important part of influenza management and include the neuraminidase inhibitors zanamivir and oseltamivir. These inhibitors can limit the infection and prevent the spread of the virus.

OBJECTIVES

To assess the effects of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 02 November 2015.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs.

DATA COLLECTION AND ANALYSIS

Two review authors had planned to independently screen studies, extract data and assess risk of bias using standard Cochrane methodologies. No studies were identified for inclusion.

MAIN RESULTS

No relevant studies were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled studies or quasi-randomised controlled studies on the efficacy of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis. The absence of high level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately powered, randomised controlled clinical studies.

Neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis

BACKGROUND

Cystic fibrosis is the most common, life-threatening, recessively inherited disease of Caucasian populations. It is a multisystem disorder caused by a mutation in the gene encoding the cystic fibrosis transmembrane conductance regulator protein which is important in producing sweat, digestive juices and mucus.The impaired or absent function of this protein results in the production of viscous mucus within the lungs and an environment that is susceptible to chronic airway obstruction and pulmonary colonization by a range of pathogenic bacteria. Morbidity and mortality of cystic fibrosis is related to chronic pulmonary sepsis and its complications by these bacteria.Influenza can worsen the course of the disease in cystic fibrosis by increasing the risk of pneumonia and secondary respiratory complications. Antiviral agents form an important part of influenza management and include the neuraminidase inhibitors zanamivir and oseltamivir. These inhibitors can limit the infection and prevent the spread of the virus.

OBJECTIVES

To assess the effects of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 08 July 2013.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs.

DATA COLLECTION AND ANALYSIS

Two review authors had planned to independently screen studies, extract data and assess risk of bias using standard Cochrane Collaboration methodologies. No studies were identified for inclusion.

MAIN RESULTS

No relevant studies were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the efficacy of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis. The absence of high level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately powered, randomised controlled clinical trials.

Influenza vaccination in children with cystic fibrosis

Cystic fibrosis (CF) is an inherited autosomal recessive disease characterized by progressive pulmonary damage and respiratory failure. It is known that bacterial infections play a critical role in the development of significant lung damage, whereas the role of respiratory viruses in CF pulmonary exacerbations and the relationship between viral infections and the progression of lung damage are uncertain. Health authorities throughout the world recommend influenza vaccination for CF patients. The aim of this review is to analyze the impact of seasonal and pandemic influenza on CF patients and data concerning influenza vaccination in order to assess the current situation and identify areas for future study. As data are limited, further well-constructed clinical studies of the effectiveness of influenza vaccination on the main clinical outcome measures of pulmonary function and nutritional status in patients with CF are required.

The role of respiratory viruses in adult patients with cystic fibrosis receiving intravenous antibiotics for a pulmonary exacerbation

BACKGROUND

Respiratory viruses have become increasingly recognised as important agents in pulmonary exacerbations in infants and children with CF. The aim of this study was to determine the prevalence of respiratory viruses during acute pulmonary exacerbations in adults and compare the severity of these exacerbations with non-viral associated exacerbations.

METHODS

This was a retrospective case control study. Viral throat swabs were taken from all patients presenting with an acute pulmonary exacerbation requiring intravenous antibiotic treatment over a 12 month period.

RESULTS

There were 432 pulmonary exacerbations in 180 adults. A positive viral PCR in 42 exacerbations indicated a prevalence of 9.7%. The commonest virus isolated was rhinovirus (n = 29, 69%) with influenza A/H1N1 in seven patients (16.7%). Exacerbations associated with a positive viral PCR had a greater fall in lung function at presentation with higher levels of inflammatory markers. They received more days of intravenous antibiotics, showed less response to treatment and had a shorter time to next pulmonary exacerbation compared to matched controls.

CONCLUSION

Viral associated pulmonary exacerbations in adults with CF are associated with more severe pulmonary involvement and respond less well to standard treatment.

Spectrum of viral infections in patients with cystic fibrosis

This review explores the extensive influence of viral infections leading to chronic deterioration of lung function in patients with cystic fibrosis (CF). The mechanisms how viral agents affect the pathogenesis as well as the inflammatory and immune response of CF are discussed. Viral infections of the upper and lower respiratory tract due to viruses in CF patients and methods for diagnosis of respiratory viruses are described in detail. The importance of respiratory and non-respiratory viral agents for the pathogenesis, especially for the exacerbation of bacterial lower respiratory tract infections and course of CF, is stressed, especially emphasizing respiratory syncytial virus, influenza virus, rhinovirus, and human herpes viruses. Possible harmful effects of further viruses like adenovirus, bocavirus, coronavirus, metapneumovirus, parainfluenzavirus on the lung function of CF patients are discussed. The potential use of adenovirus-based vectors for somatic gene therapy is mentioned.

The emerging relationship between the airway microbiota and chronic respiratory disease: clinical implications

Until recently, relationships between evidence of colonization or infection by specific microbial species and the development, persistence or exacerbation of pulmonary disease have informed our opinions of airway microbiology. However, recent applications of culture-independent tools for microbiome profiling have revealed a more diverse microbiota than previously recognized in the airways of patients with chronic pulmonary disease. New evidence indicates that the composition of airway microbiota differs in states of health and disease and with severity of symptoms and that the microbiota, as a collective entity, may contribute to pathophysiologic processes associated with chronic airway disease. Here, we review the evolution of airway microbiology studies of chronic pulmonary disease, focusing on asthma, chronic obstructive pulmonary disease and cystic fibrosis. Building on evidence derived from traditional microbiological approaches and more recent culture-independent microbiome studies, we discuss the implications of recent findings on potential microbial determinants of respiratory health or disease.

Influenza vaccination in patients with pulmonary sarcoidosis: efficacy and safety

BACKGROUND

Sarcoidosis is an inflammatory, granulomatous disorder of unknown etiology. The role of cellular and humoral immune systems in this disease is unclear, whereas dysregulation of the immune system is suggested. Patients with sarcoidosis show diverse responses while exposed to various antigens. Although influenza vaccination is recommended in pulmonary sarcoidosis, its efficacy and safety has not been investigated.

OBJECTIVES

  To evaluate safety and immunogenicity of influenza vaccine in patients with sarcoidosis.

PATIENTS/METHODS

Influenza vaccination was performed in 23 eligible patients with sarcoidosis (SP) and 26 healthy controls (HC). Antibody titers against H1N1, H3N2, and B influenza virus antigens were evaluated just before and 1 month after vaccination. Patients were followed for 6 months to assess vaccine safety.

RESULTS

Serological response and magnitude of changes in antibody titers against influenza vaccine antigens were comparable between SPs and HCs. Women showed a better serological response against B antigen (P = 0·034) than men. Twenty-four-hour urine calcium was associated with antibody response against H1N1 [correlation coefficient (CC) = 0·477, P = 0·003] and H3N2 (CC = 0·352, P = 0·028) antigens. Serum angiotensin-converting enzyme correlated negatively with antibody response against B antigen (CC = -0·331, P = 0·040). Higher residual volume was associated with fewer rises in antibody titer against H3N2 antigen (CC = -0·377, P = 0·035). No major adverse events or disease flare-up was observed during follow-up.

CONCLUSIONS

In this study, influenza vaccination did not cause any major adverse event in SPs, and their serological response was equal to HCs. Studies with larger sample size and a broader selection of subjects could help validate the results of this study.

Influenza-associated cystic fibrosis pulmonary exacerbations

BACKGROUND

Although cystic fibrosis (CF) is the most common inherited respiratory disease, the burden of influenza among individuals with CF is not well characterized.

METHODS

We used the CF Foundation Patient Registry to determine the relationship between pulmonary exacerbation incidence rate and influenza virus season from July 2003 through June 2007. The outcome of interest, pulmonary exacerbation, was defined as treatment of a respiratory illness with IV antibiotics. Each influenza season was defined as all months during which >/= 15% of laboratory tests for influenza virus were positive in the US influenza virologic surveillance system. We calculated incidence rates of pulmonary exacerbation during the influenza and summertime seasons as well as relative rates with 95% CIs. A multivariate regression model adjusted for demographic and clinical predictors.

RESULTS

In 2003, the patient cohort size was 21,506 patients, and 7,727 patients experienced at least one pulmonary exacerbation. The overall pulmonary exacerbation incidence rate in the influenza season was 595.0 per 10,000 person-months compared with a summertime baseline of 549.6 per 10,000 person-months. The incidence rate ratio was 1.08 (95% CI: 1.06, 1.10). Multivariate analysis did not change our estimate of risk (adjusted odds ratio: 1.07; 95% CI: 1.05, 1.10). An estimated annual excess of 147.6 per 10,000 person-months or an excess 2.1% of total exacerbations occur during the influenza season.

CONCLUSION

Our data demonstrate a substantial contribution of the influenza season to CF morbidity. Further studies to determine any causal link between influenza infection and CF pulmonary exacerbations are necessary.

Neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis

BACKGROUND

Cystic fibrosis is the most common, life-threatening, recessively inherited disease of Caucasian populations. It is a multisystem disorder caused by a mutation in the gene encoding the cystic fibrosis transmembrane conductance regulator protein which is important in producing sweat, digestive juices and mucus.The impaired or absent function of this protein results in the production of viscous mucus within the lungs and an environment that is susceptible to chronic airway obstruction and pulmonary colonization by a range of pathogenic bacteria. Morbidity and mortality of cystic fibrosis is related to chronic pulmonary sepsis and its complications by these bacteria.Influenza can worsen the course of the disease in cystic fibrosis by increasing the risk of pneumonia and secondary respiratory complications. Antiviral agents form an important part of influenza management and include the neuraminidase inhibitors zanamivir and oseltamivir. These inhibitors can limit the infection and prevent the spread of the virus.

OBJECTIVES

To assess the effects of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis.

SEARCH STRATEGY

We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group Trials Register comprising references identified from comprehensive electronic database searches and handsearches of relevant journals and abstract books of conference proceedings.Most recent search: 12 August 2009.

SELECTION CRITERIA

Randomised controlled trials and quasi-randomised controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs.

DATA COLLECTION AND ANALYSIS

Two review authors had planned to independently screen studies, extract data and assess risk of bias using standard Cochrane Collaboration methodologies. No studies were identified for inclusion.

MAIN RESULTS

No relevant studies were retrieved after a comprehensive search of the literature.

AUTHORS' CONCLUSIONS

We were unable to identify any randomised controlled trials or quasi-randomised controlled trials on the efficacy of neuraminidase inhibitors for the treatment of influenza infection in people with cystic fibrosis. The absence of high level evidence for the effectiveness of these interventions emphasises the need for well-designed, adequately powered, randomised controlled clinical trials.

A fusion protein vaccine containing OprF epitope 8, OprI, and type A and B flagellins promotes enhanced clearance of nonmucoid Pseudomonas aeruginosa

Although chronic Pseudomonas aeruginosa infection is the major cause of morbidity and mortality in cystic fibrosis (CF) patients, there is no approved vaccine for human use against P. aeruginosa. The goal of this study was to establish whether a multivalent vaccine containing P. aeruginosa type A and B flagellins as well as the outer membrane proteins OprF and OprI would promote enhanced clearance of P. aeruginosa. Intramuscular immunization with flagellins and OprI (separate) or OprI-flagellin fusion proteins generated significant antiflagellin immunoglobulin G (IgG) responses. However, only the fusions of OprI with type A and type B flagellins generated OprI-specific IgG. Immunization with a combination of OprF epitope 8 (OprF(311-341)), OprI, and flagellins elicited high-affinity IgG antibodies specific to flagellins, OprI, and OprF that individually promoted extensive deposition of C3 on P. aeruginosa. Although these antibodies exhibited potent antibody-dependent complement-mediated killing of nonmucoid bacteria, they were significantly less effective with mucoid isolates. Mice immunized with the OprF(311-341)-OprI-flagellin fusion had a significantly lower bacterial burden three days postchallenge and cleared the infection significantly faster than control mice. In addition, mice immunized with the OprF(311-341)-OprI-flagellin fusion had significantly less inflammation and lung damage throughout the infection than OprF-OprI-immunized mice. Based on our results, OprF(311-341)-OprI-flagellin fusion proteins have substantial potential as components of a vaccine against nonmucoid P. aeruginosa, which appears to be the phenotype of the bacterium that initially colonizes CF patients.

Influenza vaccination coverage in patients with cystic fibrosis followed at 12 care centers in the Greater South Region of France for the season 2005/2006

The objective of this observational study was to estimate influenza vaccination coverage for the 2005/2006 season in cystic fibrosis (CF) patients consulting at or hospitalized in 12 CF care centers. Data from 518 CF patients >6 months of age (children: 64.9%) were analyzed: 79.9% were vaccinated. The vaccination coverage was 85.6% in children, 69.4% in adults and 44.4% in transplanted patients. General practitioners vaccinated 67.9% of the patients. "Lack of time" reason was reported by 24.7% non-vaccinated patients. In France, influenza vaccination coverage in CF patients meets the National Health objective (> or =75% by 2008), but could be improved in adults and transplanted patients.

The role of respiratory viruses in cystic fibrosis

Background

Previous studies have suggested a role played by respiratory viruses in the exacerbation of cystic fibrosis (CF). However, the impact of respiratory viruses could have been underestimated because of the low detection rate by conventional laboratory methods.

Methods

Children with CF had nasal swabs and sputum samples obtained on a routine basis and when they developed respiratory exacerbations. Nucleic Acid Sequence Based Amplification (NASBA) was used to detect respiratory viruses from nasal swabs. The definition of a respiratory exacerbation was when the symptom score totalled to 4 or more, or if the peak expiratory flow fell by more than 50 l/min from the child's usual best value, or if the parent subjectively felt that the child was developing a cold.

Results

71 patients had 165 reported episodes of respiratory exacerbations. 138 exacerbation samples were obtained of which 63 (46%) were positive for respiratory viruses. In contrast, 23 of 136 asymptomatic nasal swabs (16.9%) were positive for respiratory viruses. There was significantly more viruses being detected during respiratory exacerbations, in particular influenza A, influenza B and rhinovirus (p < 0.05).

Upper respiratory symptoms significantly correlated with positive respiratory viral detection (p < 0.05). This study also showed that viral respiratory exacerbations in CF could be independent from bacterial infections.

Conclusions

Respiratory viruses are associated with exacerbations in CF and upper respiratory symptoms are strong predictors for their presence. ‘Real-time’ NASBA has a rapid turn-around time and has the potential to aid clinical decision making, such as the use of anti-virals and administration of antibiotics.