Contribution of influenza and respiratory syncytial virus to community cases of influenza-like illness: an observational study

Effects of influenza plus pneumococcal conjugate vaccination versus influenza vaccination alone in preventing respiratory tract infections in children: a randomized, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the effects of influenza vaccination with or without heptavalent pneumococcal conjugate vaccination on respiratory tract infections (RTIs) in children.

STUDY DESIGN

This was a randomized, double-blind, placebo-controlled trial comprising 579 children age 18 to 72 months with a previous history of physician-diagnosed RTI, recruited between 2003 and 2005. The children were assigned to 2 doses of parenteral inactivated trivalent subunit influenza plus heptavalent pneumococcal conjugate vaccination (TIV+PCV7), influenza plus placebo vaccination (TIV+plac), or control hepatitis B virus vaccination plus placebo (HBV+plac). Main outcome measures were febrile RTI and related polymerase chain reaction (PCR)-confirmed influenza, primary care visits, antibiotic prescriptions, and acute otitis media (AOM) episodes.

RESULTS

During influenza seasons, febrile RTI were reduced by 24% (95% confidence interval [CI] = 1% to 42%) in the TIV+PCV7 group and by 13% (95% CI = -12% to 32%) in the TIV+plac group compared with the control group. The occurrence of PCR-confirmed influenza was reduced by 52% (95% CI = 7% to 75%) in the TIV+PCV7 group and by 51% (95% CI = 3% to 75%) in the TIV+plac group. Episodes of AOM were reduced by 57% (95% CI = 6% to 80%) in the TIV+PCV7 group and by 71% (95% CI = 30% to 88%) in the TIV+plac group. Outside of the influenza seasons, no significant effects of vaccinations were demonstrated on the studied outcomes.

CONCLUSIONS

During influenza seasons, influenza vaccination with or without pneumococcal conjugate vaccination substantially reduced cases of confirmed influenza and AOM episodes.

Influenza A and respiratory syncytial virus hospital burden in young children in East London

Epidemiological studies have demonstrated high hospitalization rates attributable to influenza and RSV in children aged 6 months and those aged <12 months, respectively (43 and 92.5/10 000 person-months, respectively). In conclusion, these high paediatric RSV and influenza incidence rates can be used to inform UK policy on childhood influenza immunization and subsequent RSV immunization in the future.

Role of respiratory pathogens in infants hospitalized for a first episode of wheezing and their impact on recurrences

In order to evaluate the infectious agents associated with the first episode of severe acute wheezing in otherwise healthy infants and to define the role of each of them in recurrences, 85 patients in Italy, aged <12 months, hospitalized because of a first acute episode of wheezing, were prospectively enrolled between 1 October 2005 and 31 March 2006. Upon enrollment, nasopharyngeal swabs were collected for the real-time PCR detection of respiratory syncytial virus (RSV) types A and B, influenza virus types A and B, adenovirus, parainfluenza viruses types 1, 2, 3 and 4, rhinovirus, human metapneumovirus, human coronavirus types 229E, OC43, NL63, and HKU1, bocavirus, enterovirus, and paraechovirus; nasopharyngeal aspirates were also obtained to detect atypical bacteria. At least one infectious agent was identified in 76 children (89.4%). RSV was the most frequently detected pathogen and its prevalence was significantly higher than that of the other pathogens in both age groups, and significantly higher in the children aged 3-12 months than in those aged <3 months. Only the children with RSV infection experienced recurrent wheezing. Viral load was significantly higher in children with than in those without recurrent wheezing. This study shows that RSV is the main reason for hospitalization during the first wheezing episode in infants, and that it appears to be the only pathogen associated with a high frequency of recurrences. A high viral load seems to be strictly related to the likelihood of recurrence.

Cigarette smoke worsens lung inflammation and impairs resolution of influenza infection in mice

BACKGROUND

Cigarette smoke has both pro-inflammatory and immunosuppressive effects. Both active and passive cigarette smoke exposure are linked to an increased incidence and severity of respiratory virus infections, but underlying mechanisms are not well defined. We hypothesized, based on prior gene expression profiling studies, that upregulation of pro-inflammatory mediators by short term smoke exposure would be protective against a subsequent influenza infection.

METHODS

BALB/c mice were subjected to whole body smoke exposure with 9 cigarettes/day for 4 days. Mice were then infected with influenza A (H3N1, Mem71 strain), and analyzed 3 and 10 days later (d3, d10). These time points are the peak and resolution (respectively) of influenza infection.

RESULTS

Inflammatory cell influx into the bronchoalveolar lavage (BALF), inflammatory mediators, proteases, histopathology, viral titres and T lymphocyte profiles were analyzed. Compared to smoke or influenza alone, mice exposed to smoke and then influenza had more macrophages, neutrophils and total lymphocytes in BALF at d3, more macrophages in BALF at d10, lower net gelatinase activity and increased activity of tissue inhibitor of metalloprotease-1 in BALF at d3, altered profiles of key cytokines and CD4+ and CD8+ T lymphocytes, worse lung pathology and more virus-specific, activated CD8+ T lymphocytes in BALF. Mice smoke exposed before influenza infection had close to 10-fold higher lung virus titres at d3 than influenza alone mice, although all mice had cleared virus by d10, regardless of smoke exposure. Smoke exposure caused temporary weight loss and when smoking ceased after viral infection, smoke and influenza mice regained significantly less weight than smoke alone mice.

CONCLUSION

Smoke induced inflammation does not protect against influenza infection.In most respects, smoke exposure worsened the host response to influenza. This animal model may be useful in studying how smoke worsens respiratory viral infections.

Lessons from 40 years' surveillance of influenza in England and Wales

The influenza virus continues to pose a significant threat to public health throughout the world. Current avian influenza outbreaks in humans have heightened the need for improved surveillance and planning. Despite recent advances in the development of vaccines and antiviral drugs, seasonal epidemics of influenza continue to contribute significantly to general practitioner workloads, emergency hospital admissions, and deaths. In this paper we review data produced by the Royal College of General Practitioners Weekly Returns Service, a sentinel general practice surveillance network that has been in operation for over 40 years in England and Wales. We show a gradually decreasing trend in the incidence of respiratory illness associated with influenza virus infection (influenza-like illness; ILI) over the 40 years and speculate that there are limits to how far an existing virus can drift and yet produce substantial new epidemics. The burden of disease caused by influenza presented to general practitioners varies considerably by age in each winter. In the pandemic winter of 1969/70 persons of working age were most severely affected; in the serious influenza epidemic of 1989/90 children were particularly affected; in the millennium winter (in which the NHS was severely stretched) ILI was almost confined to adults, especially the elderly. Serious confounders from infections due to respiratory syncytial virus are discussed, especially in relation to assessing influenza vaccine effectiveness. Increasing pressure on hospitals during epidemic periods are shown and are attributed to changing patterns of health-care delivery.

Rate-difference method proved satisfactory in estimating the influenza burden in primary care visits

OBJECTIVE

To compare different methods to estimate the disease burden of influenza, using influenza and respiratory syncytial virus-(RSV) associated primary care data as an example.

STUDY DESIGN AND SETTING

In a retrospective study in the Netherlands over 1997-2003, primary care attended respiratory episodes and national viral surveillance data were used to compare the rate-difference method to other, more complex methods.

RESULTS

The influenza-associated excess estimated by the different methods varied. The estimates provided by the rate-difference model lay well within this range. According to the rate-difference method, influenza-associated primary care consultations were present for all ages, including low-risk adults. The highest influenza-associated burden was demonstrated for children below the age of 5 years. The RSV-associated primary care burden was highest in the youngest age category and well above that associated with influenza. Significant RSV-associated excess was also recorded among adults, particularly in high-risk adults and the elderly.

CONCLUSION

The straightforward rate-difference model seemed satisfactory to estimate the influenza-associated burden. Significant influenza-associated excess was demonstrated among persons not yet recommended for influenza vaccination in The Netherlands. The RSV-associated burden was highest for the youngest children, but also significant for adults.

Association between high nasopharyngeal viral load and disease severity in children with human metapneumovirus infection

Background

Previous studies have shown that viral genotype and viral load may play a significant role in the pathogenesis of viral infections.

Objectives

The aim of this study was to evaluate these aspects of hMPV infections in children and their household contacts.

Study design

Between 1 November 2003 and 31 March 2004, we prospectively studied 2060 children attending our Emergency Department for acute reasons. Nasopharyngeal swabs were collected upon enrolment and then tested with real-time PCR assays for the major viral causes of respiratory illness.

Results

Sixty children (2.9%) were infected by hMPV: 24 (1.2%) by hMPV A, 14 (0.7%) by hMPV B, 11 (0.5%) by untyped hMPV, and 11 (0.5%) by hMPV and an additional respiratory virus. There were no differences in disease presentation or in clinical or socioeconomic impact in relation to viral genotypes. HMPV viral load was significantly higher in children with lower respiratory tract involvement (p < 0.05), hospitalised children (p < 0.05), and the prevalence of secondary cases of a similar disease in the household of index cases (p < 0.05).

Conclusion

A high hMPV viral load correlated with disease presentation, whereas the overall clinical and socioeconomic burden caused by the two hMPV genotypes was similar.

Recombinant simian varicella viruses expressing respiratory syncytial virus antigens are immunogenic

Recombinant simian varicella viruses (rSVVs) were engineered to express respiratory syncytial virus (RSV) antigens. The RSV surface glycoprotein G and second matrix protein M2 (22k) genes were cloned into the SVV genome, and recombinant viruses were characterized in vitro and in vivo. rSVVs were also engineered to express the membrane-anchored or secreted forms of the RSV-G protein as well as an RSV G lacking its chemokine mimicry motif (CX3C), which may have different effects on priming the host immune response. The RSV genes were efficiently expressed in rSVV/RSV-infected Vero cells as RSV-G and -M2 transcripts were detected by RT-PCR, and RSV antigens were detected by immunofluorescence and immunoblot assays. The rSVVs replicated efficiently in Vero cell culture. Rhesus macaques immunized with rSVV/RSV-G and rSVV/RSV-M2 vaccines produced antibody responses to SVV and RSV antigens. The results demonstrate that recombinant varicella viruses are suitable vectors for the expression of RSV antigens and may represent a novel vaccine strategy for immunization against both pathogens.

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.

Rapid diagnosis of influenza infection in older adults: influence on clinical care in a routine clinical setting

BACKGROUND

Laboratory diagnosis of influenza has previously relied on viral isolation in culture. Rapid antigen tests (RATs) are now available but few studies have examined their use in older adults under routine clinical conditions.

OBJECTIVES

To determine the utility of the RAT in older adults presenting to a large medical center and how test results impacted clinical care.

STUDY DESIGN

Retrospective chart review of patients tested for influenza during the 2003--2004 and 2004--2005 influenza seasons. Clinical data were correlated with the results of laboratory testing.

RESULTS

Eighty-four adults tested positive for influenza. Adding the results of the RAT to symptom complexes predictive of influenza significantly enhanced the ability to diagnose influenza in the acute setting. The positive predictive value of fever plus cough increased from 32% to 92% with a positive RAT. The RAT also directed appropriate antiviral therapy. 20/22 (91%) patients with a positive RAT and symptoms < or =48 h received antiviral treatment compared to only 1/12 (8%) patients with a negative RAT and a positive culture.

CONCLUSIONS

Under routine clinical conditions rapid influenza testing enhances the ability to quickly diagnose influenza and can be used to guide early treatment decisions in older adults.

Cost-effectiveness and value of information analyses of neuraminidase inhibitors for the treatment of influenza

OBJECTIVES

To assess the cost-effectiveness of alternative strategies for the treatment of suspected influenza in otherwise healthy adults and to identify future research priorities using value of information analysis.

METHODS

A decision model was used to estimate the costs and effects, in terms of quality-adjusted life-years (QALYs) of amantadine, zanamivir, and oseltamivir for the treatment of influenza in otherwise healthy adults using data predominantly from meta-analysis of randomized controlled trials. Probabilistic sensitivity analysis using Monte Carlo simulation was conducted. The expected value of perfect information for the entire model and for individual parameters was calculated.

RESULTS

Based on mean costs and effects, zanamivir is dominated by oseltamivir. The incremental cost-effectiveness ratio for amantadine (compared with no treatment) is pound 11,000 and pound 44,000 for oseltamivir (compared with amantadine). The probability that amantadine is cost-effective at a willingness to pay of pound 30,000 per QALY is 0.74, falling to 0.49 at pound 20,000 per QALY. Global expected value of perfect information (EVPI) is pound 2 m over 15 years if a willingness to pay threshold of pound 30,000 per QALY is assumed rising to pound 9.6 m at pound 45,000 per QALY. EVPI for only one parameter exceeds pound 500,0000 at pound 30,000 per QALY: the quality of life for untreated influenza.

CONCLUSIONS

At traditionally accepted values of willingness to pay for health benefits, it is unlikely that additional research would be an efficient use of scarce resources. The only exception to this would be to examine the health-related quality of life impact of influenza in an untreated patient group. If a higher threshold value were acceptable, there are a small group of parameters that may warrant further investigation. These would, however, require comparative, potentially expensive, research studies.

Molecular epidemiology and genetic variability of respiratory syncytial virus (RSV) in Stockholm, 2002-2003

The epidemiology and genetic variability of circulating respiratory syncytial virus (RSV) strains in Stockholm during the season 2002-2003 were studied in consecutive RSV isolates derived from respiratory samples and diagnosed in the laboratory. Two hundred thirty-four viruses were sequenced. The samples were mainly from children under 1 year old (79%). The phylogeny of the N-terminal part of the G gene was studied after amplification and sequencing. One hundred fifty-two viruses belonged to subgroup B and 82 to subgroup A. The subgroup A viruses could be further divided into genotypes GA2 (25) and GA5 (57) and the subgroup B viruses into GB3 (137) and SAB1 (15) strains. These strains clustered with subgroup A and subgroup B strains from Kenya from the same period, as well as with strains from Great Britain from 1995 to 1998. The dominance of subgroup B strains in Stockholm during 2002-2003 is in agreement with findings from other parts of the world during the same years. Only two genotypes of subgroup A, GA2 and GA5, were circulating during this time, and GA2 has been circulating in Sweden for more than 20 years. Consecutive strains from the same individual displayed no variability in the sequenced region, which was also true of strains that had been passaged in cell cultures.

Impact of human bocavirus on children and their families

This study was planned to investigate the prevalence and clinical features of the illnesses associated with human bocavirus (hBoV) in children with acute disease. We prospectively enrolled all subjects aged less than 15 years attending an emergency room in Milan, Italy, on Wednesdays and Sundays between 1 November 2004 and 31 March 2005 for any acute medical reason, excluding surgical diseases and trauma. Nasopharyngeal swabs were collected at admission to detect hBoV; influenza A and B viruses; respiratory syncytial virus; human metapneumovirus; parainfluenza viruses 1, 2, 3, and 4; rhinovirus; adenovirus; and coronaviruses 229E, OC43, NL63, and HKU1 by real-time PCR. Among the 1,332 enrolled children, hBoV was the fifth most frequently detected virus (7.4%). The rate of hBoV coinfections with other viruses was significantly higher than for the other viruses (50.5% versus 27.5%; P < 0.0001). Eighty-nine of the 99 hBoV-positive children (89.9%) had a respiratory tract infection, and 10 (10.1%) had gastroenteritis. hBoV coinfections had a significantly greater clinical and socioeconomic impact on the infected children and their households than hBoV infection alone. In conclusion, these findings show that the role of hBoV infection alone seems marginal in children attending an emergency room for acute disease; its clinical and socioeconomic importance becomes relevant only when it is associated with other viruses.

Synchrony of clinical and laboratory surveillance for influenza in Hong Kong

BACKGROUND

Consultation rates of influenza-like illness (ILI) in an outpatient setting have been regarded as a good indicator of influenza virus activity in the community. As ILI-like symptoms may be caused by etiologies other than influenza, and influenza virus activity in the tropics and subtropics is less predictable than in temperate regions, the correlation between of ILI and influenza virus activity in tropical and subtropical regions is less well defined.

METHODOLOGY AND PRINCIPAL FINDINGS

In this study, we used wavelet analysis to investigate the relationship between seasonality of influenza virus activity and consultation rates of ILI reported separately by General Out-patient Clinics (GOPC) and General Practitioners (GP). During the periods 1998-2000 and 2002-2003, influenza virus activity exhibited both annual and semiannual cycles, with one peak in the winter and another in late spring or early summer. But during 2001 and 2004-2006, only annual cycles could be clearly identified. ILI consultation rates in both GOPC and GP settings share a similar non-stationary seasonal pattern. We found high coherence between ILI in GOPC and influenza virus activity for the annual cycle, but this was only significant (p<0.05) during the periods 1998-1999 and 2002-2006. For the semiannual cycle high coherence (p<0.05) was also found significant during the period 1998-1999 and year 2003 when two peaks of influenza were evident. Similarly, ILI in GP setting is also associated with influenza virus activity for both the annual and semiannual cycles. On average, oscillation of ILI in GP and of ILI in GOPC preceded influenza virus isolation by approximately four and two weeks, respectively.

CONCLUSIONS

Our findings suggest that consultation rates of ILI precede the oscillations of laboratory surveillance by at least two weeks and can be used as a predictor for influenza epidemics in Hong Kong. The validity of our model for other tropical regions needs to be explored.

A community-based, time-matched, case-control study of respiratory viruses and exacerbations of COPD

Respiratory viruses are associated with severe acute exacerbations of chronic obstructive pulmonary disease (COPD) in hospitalized patients. However, exacerbations are increasingly managed in the community, where the role of viruses is unclear. In community exacerbations, the causal association between viruses and exacerbation maybe confounded by random fluctuations in the prevalence of circulating respiratory viruses. Therefore, to determine whether viral respiratory tract infections are causally associated with community exacerbations, a time-matched case-control study was performed. Ninety-two subjects (mean age 72 yrs), with moderate to severe COPD, (mean FEV(1) 40% predicted), were enrolled. Nasopharyngeal swabs for viral multiplex polymerase chain reaction and atypical pneumonia serology were obtained at exacerbation onset. Control samples were collected in synchrony, from a randomly selected stable patient drawn from the same cohort. In 99 weeks of surveillance, there were 148 exacerbations. Odds of viral isolation were 11 times higher in cases, than their time-matched controls (34 discordant case-control pairs; in 31 pairs only the case had virus and in three pairs only control). Picornavirus (26), influenza A (3), parainfluenza 1,2,3 (2), respiratory syncytial virus (1), and adenovirus (1) were detected in cases while adenovirus (1) and picornavirus (2) were detected in controls. In patients with moderate or severe COPD the presence of a virus in upper airway secretions is strongly associated with the development of COPD exacerbations. These data support the causative role of viruses in triggering COPD exacerbations in the community.

Influenza and respiratory syncytial virus in infants and children: relationship with attendance at a paediatric emergency unit and characteristics of the circulating strains

A study was carried out on 2,696 Italian children, aged 0-14 years. The goals were: (1) to define the age-related impact of acute respiratory infections (ARI), measured as the risk of attendance at the Paediatric Emergency Room, (2) to better define the importance and proportion of influenza and respiratory syncytial virus (RSV) infections and (3) to acquire deeper knowledge of the influenza strains circulating in infants and children. A standardised emergency unit attendance risk (EUAR) was calculated, by age group for ARI. Specific EUARs were also calculated for the two pathogens. Pharyngeal swabs were tested by polymerase chain reaction (PCR) for influenza and RSVs. Isolation in Madine-Darby canine kidney cells (MDCK) and Hep cells, haemagglutination inhibition (HI) testing and HA1 gene sequence analysis were performed for influenza viruses. Most of the patients enrolled were aged 0-5 years, 1,139 (84.6%) and 1,061 (78.5%) in the two seasons, respectively. The most represented age class was that of 1 year olds (331 cases in 2001-2002 and 301 in 2002-2003). The highest EUAR for ARI was in patients aged 0-3 years (16.8 and 12.9 during the two seasons). The same was observed on calculating this risk by specific pathogens: 17.4 and 5.5 for influenza and 13.0 and 12.7 for RSV. Virological analysis was performed on 2,696 samples, 595 of which proved positive (22%). The highest number of isolates (326) came from patients aged 1-3 years. RSVs were more often identified than influenza viruses in infants aged up to 1 year (32 vs. 20 isolates). Of 265 strains isolated in 2001-2002, 103 were RSVs (87 type A, 16 B) and 162 were influenza (90 type A, 72 B). HI showed that influenza B viruses were related to two lineages, B/Victoria/2/87 (32%) and B/Yamagata/16/88 (68%). Of 330 strains isolated in 2002-2003, 102 were RSVs (91 type A, 11 B) and 228 were influenza viruses (220 type A, 8 B). A/H3N2 strains belonged to two clusters, A/Panama/2007/99-like and A/Fujian/411/02-like, a new variant. This paper discusses the possible role of the identified flu strains in determining EUARs among the population by age class.

Community-acquired viral pneumonia

Advanced age often is associated with functional and immunologic decline and chronic cardiopulmonary diseases that predispose to pneumonia when viral infection occurs. Influenza virus remains the primary viral pathogen in the elderly, although the impact of the other respiratory viruses remains to be defined. The clinical syndromes associated with respiratory viruses frequently are indistinguishable from one another or bacterial pathogens; often, viral illness in older adults exacerbates underlying conditions, complicating diagnosis. Antiviral therapy is available for influenza A and B; specific viral diagnosis, particularly with the use of rapid antigen detection, may be useful for clinical management. Treatment for other viruses primarily is supportive.

Long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma

To evaluate long-term immunogenicity of a virosomal subunit inactivated influenza vaccine in children with asthma, a prospective study was conducted during 2005-2006 influenza season in six public pediatric clinics in Milan and surroundings, Northern Italy. A single dose (0.5 ml) of a virosomal subunit inactivated influenza vaccine (Inflexal V) was injected in 106 asthmatic children aged 3-9 years. Serum hemagglutinin inhibition antibody titers were determined against the recommended influenza strains A/New Caledonia (H1N1), A/California (H3N2), and B/Shanghai (B), at pre-vaccination and 1 and 6 months after vaccination. Seroconversion rate (95% CI) against the strains A/H1N1, A/H3N2 and B was, respectively, 78% (68.6-85.7), 57% (46.7-66.9) and 66% (55.8-71.2) at 1 month. Seroprotection (titer> or =40) rate for A/H1N1, A/H3N2 and B was, respectively, 87% (77.8-92.2), 82% (72.6-89.7) and 90% (82.6-94.8) at 1 month and 74% (64.3-82.3), 77% (67.5-84.8), and 77% (67.5-84.8) at 6 months. Seroprotection rate was high and persistent (>95%) in children with pre-existing antibodies (titer> or =10) at pre-vaccination for any specific strain. In children without pre-existing antibodies, seroprotection rate for A/H1N1, A/H3N2 and B was, respectively, 67.6%, 66.7% and 74.4% at 1 month, and 35.1%, 56.2% and 41.0% at 6 months after vaccination. Vaccine was well tolerated. These results indicate that in unvaccinated children with asthma vaccination with a single dose of virosomal-adjuvanted influenza vaccine is well tolerated and effective as a whole. However, while immunity response and persistence are excellently high in children with pre-existing antibodies, in children naive for the antigens the immune parameters are lower at 6 months after vaccination.

The contribution of respiratory pathogens to the seasonality of NHS Direct calls

Objectives

Primary care is thought to bear half the cost of treating infections in the UK. We describe the seasonal variation in NHS Direct respiratory calls (a new source of primary care data) and estimate the contribution of specific respiratory pathogens to this variation.

Methods

Linear regression models were used to estimate the weekly contribution of specific respiratory pathogens to the volume of NHS Direct respiratory calls (England and Wales, 2002–2004, all ages and 0–4 years).

Results

Annual peaks in NHS Direct cough and difficulty breathing calls occurred in late December, with peaks in ‘cold/flu’ and fever calls occurring between November and April. The main explanatory variables were influenza (estimated to account for 72.5 calls per 100,000/year; 22% of ‘cold/flu’ calls; 15% of cough; and 13% of fever) and Streptococcus pneumoniae (55.5 per 100,000; 33% of ‘cold/flu’ calls; 20% of cough; and 15% of fever (0–4 years)).

Conclusions

It is estimated that respiratory viruses, notably influenza and RSV, are responsible for at least 50% of the seasonal variation in NHS Direct respiratory calls. These results provide estimates of the burden of specific respiratory diseases reported to NHS Direct, and will help interpret syndromic surveillance data used to provide early warning of rises in community morbidity.

Morbidity profiles of patients consulting during influenza and respiratory syncytial virus active periods

We compared the burden of illness due to a spectrum of respiratory diagnostic categories among persons presenting in a sentinel general practice network in England and Wales during periods of influenza and of respiratory syncytial virus (RSV) activity. During all periods of viral activity, incidence rates of influenza-like illness, bronchitis and common cold were elevated compared to those in baseline periods. Excess rates per 100,000 of acute bronchitis were greater in children aged <1 year (median difference 2702, 95% CI 929-4867) and in children aged 1-4 years (994, 95% CI 338-1747) during RSV active periods rather than influenza; estimates for the two viruses were similar in other age groups. Excess rates of influenza-like illness in all age groups were clearly associated with influenza virus activity. For common cold the estimates of median excess rates were significantly higher in RSV active periods for the age groups <1 year (3728, 95% CI 632-5867) and 5-14 years (339, 95% CI 59-768); estimates were similar in other age groups for the two viruses. The clinical burden of disease associated with RSV is as great if not greater than influenza in patients of all ages presenting to general practitioners.

Neuraminidase inhibitors for preventing and treating influenza in children

BACKGROUND

During epidemic years, influenza attack rates in children exceed 40%. Options for prevention and treatment include the neuraminidase inhibitors: zanamivir and oseltamivir.

OBJECTIVES

To assess the efficacy, safety and tolerability of neuraminidase inhibitors in the treatment and prevention of influenza infection in children.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005); MEDLINE (1966 to April 2005); EMBASE (January 1980 to December 2004); the on-line GlaxoSmithKline Clinical Trials Register; the on-line Roche Clinical Trial Protocol Registry and Clinical Trial Results Database (August 2005); and reference lists of articles. We also scrutinised web sites of European and US regulatory bodies and contacted manufacturers and authors.

SELECTION CRITERIA

Double-blind, randomised, controlled trials comparing neuraminidase inhibitors with placebo or other antiviral drugs in children less than 12 years of age. Additional safety and tolerability data from other sources were also included.

DATA COLLECTION AND ANALYSIS

Four authors applied the inclusion criteria to the retrieved studies, assessed trial quality and extracted data. Data were analysed separately for oseltamivir and zanamivir.

MAIN RESULTS

Three trials involving 1500 children with a clinical case definition of influenza were included, of whom 977 had laboratory-confirmed influenza. Overall, trial quality was good. Oseltamivir reduced the median duration of illness by 26% (36 hours) in healthy children with laboratory-confirmed influenza (P value less than 0.0001). The reduction was only 7.7% (10 hours) in 'at risk' (asthmatic) children, and this did not reach statistical significance (P value = 0.54). Zanamivir reduced the median duration of illness by 24% (1.25 days) in healthy children with laboratory-confirmed influenza (P value less than 0.001). No data in 'at risk' children were available. Only oseltamivir produced a significant reduction in the complications of influenza (particularly otitis media), although there was a trend to benefit for zanamivir. We identified one randomised, controlled trial of oseltamivir for the prevention of influenza transmission in households, reporting data from 222 paediatric contacts. Where index cases had laboratory-confirmed influenza, a protective efficacy of 55% was observed, but this did not reach statistical significance (P value = 0.089). The adverse events profile of zanamivir was no worse than placebo, but vomiting was more common in children treated with oseltamivir.

AUTHORS' CONCLUSIONS

Neuraminidase inhibitors are effective in shortening illness duration in healthy children with influenza, but efficacy in 'at risk' children remains to be proven. Oseltamivir is also effective in reducing the incidence of secondary complications, and may be effective for influenza prophylaxis.

Respiratory Syncytial Virus Infection in Adults

Originally considered as only a paediatric pathogen, respiratory syncytial virus (RSV) has recently been shown to be a significant cause of respiratory illness among elderly and high-risk adults. Approximately 170,000 hospitalizations and 10,000 deaths associated with RSV occur annually in people over the age of 65 years in the United States. Although rhinorrhoea and wheezing are common symptoms among adults, the clinical syndrome associated with RSV is not distinctive and thus laboratory methods are required for specific diagnosis. Presently, the combination of reverse transcription PCR and enzyme immunoassay serology offers the best sensitivity and specificity for diagnosis of RSV. Treatment options are limited at present, with inhaled ribavirin being the only licensed drug for use in hospitalized children. Vaccines against RSV remain an unachieved goal. Promising new agents that inhibit the virus-cell fusion, cell-cell fusion, or viral gene expression are currently in development.

Influenza- and RSV-associated hospitalizations among adults

We estimated influenza- and respiratory syncytial virus (RSV)-associated hospitalizations by age, high-risk status and outcome, during the 1996/1997-1999/2000 respiratory seasons among adults who did not receive influenza vaccine. Using three health maintenance organization (HMO) databases and local viral surveillance data, we identified weeks when influenza and RSV were circulating and estimated influenza- and RSV-associated hospitalizations. Persons aged > or = 65 years with and without high-risk conditions had significantly increased rates of influenza-associated hospitalizations for pneumonia and influenza, and circulatory and respiratory diseases. Persons aged > or = 65 years with high-risk conditions also had significantly increased rates of influenza-associated hospitalizations for cardiac conditions (16.9 per 10,000 person periods). Relative to the influenza estimates for high-risk persons > or = 65 years, we found lower rates of RSV-associated hospitalizations for pneumonia and influenza diseases (23.4 per 10,000 person periods), cardiac diseases (4.3 per 10,000 person periods) and circulatory and respiratory diseases (44.0 per 10,000 person periods). Among low-risk persons aged 50-64 years, we did not identify significantly elevated rates of influenza- or RSV-associated hospitalizations. Excess hospitalization estimates among adults aged > or = 65 years and high-risk 50-64 year olds during the influenza season suggest that these groups should have priority for influenza vaccine during vaccine shortages.

Impact of rapid viral testing for influenza A and B viruses on management of febrile infants without signs of focal infection

BACKGROUND

The objective of this study was to assess the effect of rapid testing for influenza virus on management of febrile young infants.

METHODS

During 2 influenza seasons (November to December 2003 and December 2004 to February 2005), we studied prospectively infants who were 0 to 36 months of age who presented to the emergency department (ED) with fever in the absence of signs of focal infection. The Directigen Flu A+B test was used to determine infection with influenza virus types A or B. Confirmatory viral cultures were not done.

RESULTS

Rapid influenza testing was performed in 206 infants and 84 (40.7%) of them were influenza-positive. Infants with a positive and a negative influenza test showed a similar mean (standard deviation) age (6.86 [6.3] versus 6.55 [6.8] months) and mean temperature (39.38 degrees C [0.6] versus 39.32 degrees C [0.8]), but there were significant differences (P < 0.01) in the percentage of patients undergoing blood tests (33.3% versus 100%), urinalysis (80.9% versus 100%), chest roentgenogram (14.2% versus 32%), cerebrospinal fluid analysis (1.33% versus 21.3%), mean length of stay in the ED (116.2 [75.5] versus 192.9 [76.3] minutes), admission to the ED observation ward (8.3% versus 21.3%), inpatient care (2.3% versus 16.4%) and antibiotic treatment (0% versus 38.5%). All positive bacterial cultures occurred among influenza-negative patients.

CONCLUSIONS

The inclusion of rapid influenza testing for the evaluation of febrile young infants without signs of focal infection during influenza season decreases the need for additional studies and reduces the length of stay in the ED, the use of antibiotic treatment and unnecessary hospitalizations.

Efficacy of a paracetamol-pseudoephedrine combination for treatment of nasal congestion and pain-related symptoms in upper respiratory tract infection

OBJECTIVE

This study compared the efficacy of 1000 mg of paracetamol combined with 60 mg of pseudoephedrine, with that of either paracetamol or pseudoephedrine alone and placebo for the treatment of symptomatic URTI.

RESEARCH DESIGN AND METHODS

A double-blind, parallel group study was performed on 305 patients with URTI (nasal airflow resistance [NAR] of > 0.25 Pa cm3 s and a global pain score of at least moderate intensity). NAR and pain relief/intensity scores were measured over 4 h after initial dose. Patients then dosed up to three times daily for 3 days and recorded nasal congestion and pain intensity scores.

MAIN OUTCOME MEASURES

Nasal airflow conductance (NAC) and pain relief after the initial dose were primary objectives. NAC was calculated from NAR. Pain relief was measured on a 5-point verbal rating scale (VRS) and pain intensity and nasal congestion on a 4-point VRS. Data were analysed using analysis of covariance. Safety was assessed by adverse events.

RESULTS

A single dose of the combination was superior to paracetamol and placebo for NAC (p = 0.0001) and was superior to pseudoephedrine and placebo for pain relief (p < or = 0.048). Multiple doses of the combination were also superior to paracetamol and placebo for decongestion (p < or = 0.021) and were superior to pseudoephedrine and placebo for pain reduction (p < or = 0.0057). All treatments were well tolerated.

CONCLUSIONS

The combination treatment provided a greater decongestant effect than either paracetamol or placebo and better pain relief than either pseudoephedrine or placebo. The additive effect of the combination was apparent for both single and multiple doses.

Distinct patterns of evolution between respiratory syncytial virus subgroups A and B from New Zealand isolates collected over thirty-seven years

Respiratory syncytial virus (RSV) is the most important cause of viral lower respiratory tract infections in infants and children worldwide. In New Zealand, infants with RSV disease are hospitalized at a higher rate than other industrialized countries, without a proportionate increase in known risk factors. The molecular epidemiology of RSV in New Zealand has never been described. Therefore, we analyzed viral attachment glycoprotein (G) gene sequences from 106 RSV subgroup A isolates collected in New Zealand between 1967 and 2003, and 38 subgroup B viruses collected between 1984 and 2004. Subgroup A and B sequences were aligned separately, and compared to sequences of viruses isolated from other countries during a similar period. Genotyping and clustering analyses showed RSV in New Zealand is similar and temporally related to viruses found in other countries. By quantifying temporal clustering, we found subgroup B viruses clustered more strongly than subgroup A viruses. RSV B sequences displayed more variability in stop codon usage and predicted protein length, and had a higher degree of predicted O-glycosylation site changes than RSV A. The mutation rate calculated for the RSV B G gene was significantly higher than for RSV A. Together, these data reveal that RSV subgroups exhibit different patterns of evolution, with subgroup B viruses evolving faster than A.

Influenza vaccination: the paediatric perspective

Influenza in young children represents a significant problem to families and to society, as this population is most susceptible to developing complications and is also a major route of disease spread within communities. However, there is a paucity of European data for the burden of disease in children and the health benefits and cost-effectiveness of vaccination, leading to a lack of awareness by governments, authorities, healthcare professionals and parents. The experience in elderly individuals and the paediatric experience in the US may provide some guidance in developing studies that will provide evidence for the creation of guidelines and educational strategies within Europe.

Respiratory viral infections in adults with hematologic malignancies and human stem cell transplantation recipients: a retrospective study at a major cancer center

Community respiratory viruses (CRVs) have been recognized as a potential cause of pneumonia and death among hematopoietic stem cell transplantation (HSCT) recipients and patients with hematologic malignancies. We reviewed the Microbiology Laboratory records dated from July 1, 2000, to June 30, 2002, to identify patients who had respiratory specimens positive for influenza, parainfluenza, respiratory syncytial virus, or picornavirus. We identified 343 infections among patients with underlying hematologic malignancies and HSCT. We collected data on type of disease, age, sex, type of infection, neutrophil and lymphocyte counts, therapy, and outcome. Influenza, parainfluenza, and respiratory syncytial virus accounted for most cases and were approximately equal in frequency. Most infections occurred predominantly among recipients of allogeneic transplants. Infection progressed to pneumonia in 119 patients (35%) and occurred with similar frequency for the 3 viruses. Patients at greatest risk for developing pneumonia included those with leukemia, those aged more than 65 years, and those with severe neutropenia or lymphopenia. Lack of respiratory syncytial virus-directed antiviral therapy (p=0.025) and age (p=0.042) were associated with development of respiratory syncytial virus pneumonia, and an absolute lymphocyte count<or=200 cells/mL (p=0.049) was associated with development of influenza pneumonia. The overall mortality rate for CRV pneumonia was 15%. The only independent predictor of fatal outcome was an absolute lymphocyte count<or=200 cells/mL (p=0.03) in patients with influenza pneumonia.HSCT recipients and patients with hematologic malignancies who develop upper respiratory infection due to CRVs should be considered for antiviral therapy of proven efficacy to reduce the risk of pneumonia and death.

Surveillance recommendations based on an exploratory analysis of respiratory syncytial virus reports derived from the European Influenza Surveillance System

Background

Respiratory syncytial virus (RSV) is an important pathogen that can cause severe illness in infants and young children. In this study, we assessed whether data on RSV collected by the European Influenza Surveillance Scheme (EISS) could be used to build an RSV surveillance system in Europe.

Methods

Influenza and RSV data for the 2002–2003 winter season were analysed for England, France, the Netherlands and Scotland. Data from sentinel physician networks and other sources, mainly hospitals, were collected. Respiratory specimens were tested for influenza and RSV mainly by virus culture and polymerase chain reaction amplification.

Results

Data on RSV were entered timely into the EISS database. RSV contributed noticeably to influenza-like illness: in England sentinel RSV detections were common in all age groups, but particularly in young children with 20 (40.8%) of the total number of sentinel swabs testing positive for RSV. Scotland and France also reported the highest percentages of RSV detections in the 0–4 year age group, respectively 10.3% (N = 29) and 12.2% (N = 426). In the Netherlands, RSV was detected in one person aged over 65 years.

Conclusion

We recommend that respiratory specimens collected in influenza surveillance are also tested systematically for RSV and emphasize the use of both community derived data and data from hospitals for RSV surveillance. RSV data from the EISS have been entered in a timely manner and we consider that the EISS model can be used to develop an RSV surveillance system equivalent to the influenza surveillance in Europe.

The relationship between respiratory syncytial virus infections and the development of wheezing and asthma in children

PURPOSE OF REVIEW

The relationship between respiratory syncytial virus lower-respiratory-tract infections in early childhood and asthma has been the subject of much debate. Most, but not all, previous cohort studies have failed to identify a link between early respiratory syncytial virus infection and atopic asthma. Recent studies have helped clarify some apparently contradictory findings.

RECENT FINDINGS

Cohort studies focusing on wheezing in early childhood have indicated that this is associated with an increased incidence of atopic asthma but that this risk is not increased by respiratory syncytial virus infection. Indeed, wheeze associated with rhinovirus infection may be a better marker for possible asthma. In contrast, there is no increased risk of atopic disease in infants with respiratory syncytial virus 'acute bronchiolitis', a phenotype characterized by widespread crepitation. Post-bronchiolitic symptoms are associated with intercurrent viral infections in particular and the incidence of symptoms falls rapidly during infancy.

SUMMARY

These studies confirm earlier suggestions that the phenotype of respiratory illness and hence the host response rather than the infecting organism is the best predictor of the future pattern of respiratory illness. Such considerations must be central to the design of any future intervention or cohort studies.

Epidemiology of human metapneumovirus

Since the discovery of human metapneumovirus (hMPV) in 2001, the virus has been identified worldwide. hMPV is a common respiratory pathogen, particularly in infants and young children. The virus is associated with both upper and lower respiratory tract infections and may be a trigger for asthma. At least two major genotypes of hMPV circulate during community outbreaks. Whether these genotypes represent distinct serotypes remains controversial. The major challenges faced by the medical and scientific communities are the understanding of the pathogenesis of hMPV disease and the development of a safe and effective vaccine to protect against infection and disease caused by this newly recognized respiratory virus.

Antisense approaches for inhibiting respiratory syncytial virus

Respiratory syncytial virus (RSV) continues as an emerging infectious disease not only among infants and children, but also for the immune-suppressed, hospitalised and the elderly. To date, ribavirin (Virazole, ICN Pharmaceuticals, Inc.) remains the only therapeutic agent approved for the treatment of RSV. However, its clinical benefits are small and occur only in a fraction of RSV-infected patients. The prophylactic administration of palivizumab (Synagis, MedImmune, Inc.) is problematic and costly and, therefore, only recommended for use in high-risk infants. Clearly, the need for an effective and safe drug remains high. This review discusses several different antisense approaches and compares them with traditional strategies, such as RSV-targeting antibodies and antivirals, as well as developments in vaccine research.

Comparison of human metapneumovirus, respiratory syncytial virus and influenza A virus lower respiratory tract infections in hospitalized young children

BACKGROUND

We compared the clinical and demographic features of children with lower respiratory tract infection (LRI) caused by human metapneumovirus (HMPV), respiratory syncytial virus (RSV) and influenza A virus and sought to determine whether coinfection by HMPV and other respiratory viruses leads to increased disease severity.

METHODS

Nasal wash specimens were prospectively obtained from 516 children hospitalized for LRI during a 1-year period and tested for the presence of HMPV by reverse transcription-polymerase chain reaction and for RSV and influenza A by direct immunofluorescence.

RESULTS

HMPV was detected in 68 (13%) patients and was the third most common viral pathogen; 16 of 68 HMPV-positive children (24%) had coinfection with other respiratory viruses (HMPVco).HMPV patients were older than RSV patients (17.6 +/- 16.8 months versus 10.5 +/- 11.8 months, P = 0.02). HMPV was associated with wheezing and hypoxemia at a rate similar to that of RSV and higher than that of influenza A. Atelectasis was more common among HMPV (40%) than among RSV and influenza patients (13%, P < 0.05 for each). HMPV infection was more often associated with a diagnosis of pneumonia than RSV and influenza A and was more often associated with a diagnosis of asthma and less often associated with a diagnosis of bronchiolitis than RSV infection (P < 0.05 for each), even when corrected for age. Children with HMPVco had a higher rate of gastrointestinal symptoms but did not show a more severe respiratory picture.

CONCLUSIONS

The clinical pattern of HMPV more closely resembles that of RSV than that of influenza A LRI, yet the differences in age, radiographic findings and clinical diagnosis suggest that HMPV pathogenesis may differ from that of RSV.

Implementation of the community network of reference laboratories for human influenza in Europe

BACKGROUND

The increased need for accurate influenza laboratory surveillance data in the European Union required formalisation of the existing network of collaborating national influenza reference laboratories participating in the European Influenza Surveillance Scheme (EISS).

OBJECTIVE

To establish a Community Network of Reference Laboratories for Human Influenza in Europe (CNRL).

METHODS

Virologists in EISS defined the objective and tasks of the CNRL. Performance of the laboratories in the tasks was monitored by questionnaire-based inventories and quality control assessments (QCA). Subsequently, actions were defined to improve the performance of the CNRL.

RESULTS

The CNRL started in April 2003 and included as of May 2004 32 laboratories in 24 European countries. The objective is to provide high quality reference services for human influenza surveillance, early warning and pandemic preparedness in Europe. The defined basic tasks are direct detection, culture, typing, subtyping and strain characterisation of influenza virus, diagnostic influenza serology and storage of clinical specimens and virus isolates. The questionnaire-based inventories and QCAs revealed that the majority of CNRL laboratories perform well in most of the basic tasks, although improvements are needed in certain areas of virus testing. Therefore, task groups have been established to further improve the methods used in the network. The CNRL has proven its usefulness during the 2003-2004 season by the reporting of accurate data concerning the flu epidemic caused by A/Fujian/411/2002 (H3N2)-like viruses and by the rapid sharing of information, protocols and reagents during the A(H5N1) and A(H7N3) epizootics in Asia and Canada.

CONCLUSION

EISS has established a functioning Community Network of Reference Laboratories for Human Influenza in Europe and laid the foundation for further enhancement and collaborations. Important next steps include improving the laboratories to carry out all basic tasks and collaboration with the European Centre for Disease Prevention and Control.

The association of respiratory syncytial virus infection and influenza with emergency admissions for respiratory disease in London: an analysis of routine surveillance data

BACKGROUND

The importance of respiratory syncytial virus (RSV) infection in adults is not well known, because laboratory testing for RSV infection is not routine. Both RSV infection and influenza are seasonally related, and it is difficult to disentangle one from the other and to disentangle infection from the season and the cold.

METHODS

Emergency hospitalizations for respiratory disease from April 1994 to March 2001 were analyzed in relation to surveillance data on RSV infection and influenza, using Poisson regression models adapted for time series and adjusted for season, outdoor temperature, and other covariates. Age-specific admission rates attributable to the viruses were also estimated.

RESULTS

Most of the crude relationships of emergency admissions of patients with RSV infection were confounded by season and, to a lesser extent, by cold temperatures. After adjustment for all covariates, including influenza, a 10th-90th percentile increase in RSV counts (defined as the daily number of laboratory reports of RSV) was associated with a rate ratio of 1.36 (95% CI, 1.27-1.45) for emergency admissions for respiratory disease in infants. The rate of hospitalization attributable to RSV infection in children aged <1 year was 5 per 1000 infants per year. The association in people > or =65 years old was much smaller (rate ratio, 1.09; 95% CI, 1.04-1.14; attributable rate of hospitalization , 0.7 per 1000 population); but unlike the association in infants, this association became smaller as the lag (interval) between infection and hospital admission became shorter. Admission rates attributable to influenza were highest in the > or =65-year age group (1.1 per 1000 population), but it was very small at younger ages.

CONCLUSIONS

RSV infection appears to be an important determinant of hospitalization in infants in this data set but appears less certain for older persons and requires further investigation.

The cost of influenza in Thailand

The cost of influenza in less wealthy tropical countries is needed to inform national vaccine policy decisions. Between September 2003 and August 2004, we prospectively identified hospitalized pneumonia cases and outpatients with laboratory confirmed influenza in a Thai province. Disease incidence, patient interviews, medical record reviews, and data from a national health survey were used to calculate direct and indirect costs which were extrapolated to the Thai population. Influenza was identified in 80 (11%) of 761 hospitalized pneumonia inpatients with projected annual incidence of 18-111/100,000 population. Influenza was confirmed in 23% of 1092 outpatients with an estimated annual incidence of 1420/100,000 population. Influenza was estimated to cause between US dollar 23.4 and US dollar 62.9 million in economic losses with lost productivity accounting for 56% of all costs. The burden of influenza in Thailand is greater than previously appreciated, particularly in young children and the elderly. The impact and cost-effectiveness of influenza vaccination for high-risk groups merits further investigation.

Rates of hospitalisation for influenza, respiratory syncytial virus and human metapneumovirus among infants and young children

To inform the development of a national influenza immunisation programme and the potential role of antiviral drugs in young children, we studied 613 children aged 71 months or younger who attended Leicester Childrens' Hospital during winter 2001-2002. During periods of respiratory syncytial virus (RSV), influenza, and human metapneumovirus activity, an estimated 12.2% (95% CI: 11.4-13.1), 7.1% (6.3-7.9), and 2.5% (2.1-2.9), respectively, of all medical cases assessed in the hospital were associated with these infections. The respective rates of hospital assessments for RSV, influenza, and human metapneumovirus (HMPV) were 1042 (95% CI: 967-1021), 394 (348-443), and 223 (189-262) per 100,000 children, and for admissions were 517 (465-574), 144 (117-175), and 126 (101-156) per 100,000. Few children with influenza had a prior risk factor. Children with influenza were admitted a median of 4 days after onset of illness and none was coded at discharge as influenza. We conclude that antivirals have little role in the hospital management of children with influenza. Our data provide health economists with information to evaluate the place of universal immunisation of young children against influenza. Hospitalisation rates decreased markedly with referral age, so vaccine would need to be given in early infancy for maximum benefit.

Chronic cough due to acute bronchitis: ACCP evidence-based clinical practice guidelines

BACKGROUND

The purpose of this review is to present the evidence for the diagnosis and treatment of cough due to acute bronchitis and make recommendations that will be useful for clinical practice. Acute bronchitis is one of the most common diagnoses made by primary care clinicians and emergency department physicians. It is an acute respiratory infection with a normal chest radiograph that is manifested by cough with or without phlegm production that lasts for up to 3 weeks. Respiratory viruses appear to be the most common cause of acute bronchitis; however, the organism responsible is rarely identified in clinical practice because viral cultures and serologic assays are not routinely performed. Fewer than 10% of patients will have a bacterial infection diagnosed as the cause of bronchitis. The diagnosis of acute bronchitis should be made only when there is no clinical or radiographic evidence of pneumonia, and the common cold, acute asthma, or an exacerbation of COPD have been ruled out as the cause of cough. Acute bronchitis is a self-limited respiratory disorder, and when the cough persists for >3 weeks, other diagnoses must be considered.

METHODS

Recommendations for this review were obtained from data using a National Library of Medicine (PubMed) search dating back to 1950, which was performed in August 2004. The search was limited to literature published in the English language and human studies, using search terms such as "cough," "acute bronchitis," and "acute viral respiratory infection."

RESULTS

Unfortunately, most previous controlled trials guiding the treatment of acute bronchitis have not vigorously differentiated acute bronchitis and the common cold, and also have not distinguished between an acute exacerbation of chronic bronchitis and acute asthma as a cause of acute cough. For patients with the putative diagnosis of acute bronchitis, routine treatment with antibiotics is not justified and should not be offered. Antitussive agents are occasionally useful and can be offered as therapy for short-term symptomatic relief of coughing, but there is no role for inhaled bronchodilator or expectorant therapy. Children and adult patients with confirmed and probable whooping cough should receive a macrolide antibiotic and should be isolated for 5 days from the start of treatment; early treatment within the first few weeks will diminish the coughing paroxysms and prevent spread of the disease; the patient is unlikely to respond to treatment beyond this period.

CONCLUSION

Acute bronchitis is an acute respiratory infection that is manifested by cough and, at times, sputum production that lasts for no more than 3 weeks. This syndrome should be distinguished from the common cold, an acute exacerbation of chronic bronchitis, and acute asthma as the cause of acute cough. The widespread use of antibiotics for the treatment of acute bronchitis is not justified, and vigorous efforts to curtail their use should be encouraged.

Clinical and socio-economic impact of influenza and respiratory syncytial virus infection on healthy children and their households

This prospective study compared the clinical and socio-economic impact of laboratory-confirmed influenza and respiratory syncytial virus (RSV) infection on healthy children and their families. Among 1,520 otherwise healthy children aged< 15 years attending the Emergency Department for acute conditions other than trauma, influenza viruses and RSV were found in 234 (15.4%) and 116 (7.6%; p<0.0001) patients, respectively. The fact that influenza has a similar global clinical impact on the community to that of RSV infection, but represents a greater socio-economic burden, may contribute to broadening the acceptance of influenza vaccination.