Incidence of influenza and associated illness in children aged 0-19 years: a systematic review

Clinical characteristics and prognostic marker for hospitalization in children with influenza infection in an emergency setting

BACKGROUND

Influenza is a main cause of illnesses during seasonal outbreaks. Identifying children with influenza who may need hospitalization may lead to better influenza outcomes.

OBJECTIVE

To identify factors associated with the severity of influenza infection, specifically among children who were admitted to the hospital after being diagnosed with influenza at the emergency department.

METHODS

A retrospective cohort study was conducted among pediatric patients (age < 18 years) with a positive influenza rapid test who visited the emergency department at Srinagarind hospital between January2015-December2019. The dependent variable was hospital admission, while the independent variables included clinical parameters, laboratory results, and emergency severity index(ESI). The association between these variables and hospital admission was analyzed.

RESULTS

There were 542 cases of influenza included in the study. The mean age was 7.50 ± 4.52 years. Males accounted for 52.4% of the cases. A total of 190(35.05%) patients, needed hospitalization. Patients with pneumonia, those who required hospitalization or were admitted to the critical care unit, consistently exhibited an elevated absolute monocyte count and a reduced lymphocyte-to-monocyte ratio (LMR). Various factors contribute to an increased risk for hospitalization, including ESI level 1-2, co-morbidity in patients, age < 1 year old, and an LMR below 2.

CONCLUSIONS

ESI level 1-2 and co-morbidity in patients represent significant risk factors that contribute to higher hospitalization admissions. A LMR below 2 can be used as a prognostic marker for hospitalization in children with influenza infection.

Influenza and other respiratory viral infections associated with absence from school among schoolchildren in Pittsburgh, Pennsylvania, USA: a cohort study

Background

Information on the etiology and age-specific burden of respiratory viral infections among school-aged children remains limited. Though school aged children are often recognized as driving the transmission of influenza as well as other respiratory viruses, little detailed information is available on the distribution of respiratory infections among children of different ages within this group. Factors other than age including gender and time spent in school may also be important in determining risk of infection but have been little studied in this age group.

Methods

We conducted a cohort study to determine the etiology of influenza like illness (ILI) among 2519 K–12 students during the 2012–13 influenza season. We obtained nasal swabs from students with ILI-related absences. Generalized linear mixed-effect regressions determined associations of outcomes, including ILI and laboratory-confirmed respiratory virus infection, with school grade and other covariates.

Results

Overall, 459 swabs were obtained from 552 ILI–related absences. Respiratory viruses were found in 292 (63.6%) samples. Influenza was found in 189 (41.2%) samples. With influenza B found in 134 (70.9%). Rates of influenza B were significantly higher in grades 1 (10.1, 95% CI 6.8–14.4%), 2 (9.7, 6.6–13.6%), 3 (9.3, 6.3–13.2%), and 4 (9.9, 6.8–13.8%) than in kindergarteners (3.2, 1.5–6.0%). After accounting for grade, sex and self-reported vaccination status, influenza B infection risk was lower among kindergarteners in half-day programs compared to kindergarteners in full-day programs (OR = 0.19; 95% CI 0.08–0.45).

Conclusions

ILI and influenza infection is concentrated in younger schoolchildren. Reduced infection by respiratory viruses is associated with a truncated school day for kindergarteners but this finding requires further investigation in other grades and populations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-05922-1.

Influenza A and B in a cohort of outpatient children and adolescent with influenza like-illness during two consecutive influenza seasons

INTRODUCTION

Influenza is an important cause of morbimortality worldwide. Although people at the extremes of age have a greater risk of complications, influenza has been more frequently investigated in the elderly than in children, and inpatients than outpatients. Yearly vaccination with trivalent or quadrivalent vaccines is the main strategy to control influenza.

OBJECTIVES

Determine the clinical and molecular characteristics of influenza A and B infections in children and adolescents with influenza-like illness (ILI).

METHODS

A cohort of outpatient children and adolescents with ILI was followed for 20 months. Influenza was diagnosed with commercial multiplex PCR platforms.

RESULTS

179 patients had 277 episodes of ILI, being 79 episodes of influenza A and 20 episodes of influenza B. Influenza A and B cases were mild and had similar presentation. Phylogenetic tree of influenza B viruses showed that 91.6% belonged to the B/Yamagata lineage, which is not included in trivalent vaccines.

CONCLUSIONS

Influenza A and B are often detected in children and adolescents with ILI episodes, with similar and mild presentation in outpatients. The mismatch between the circulating influenza viruses and the trivalent vaccine offered in Brazil may have contributed to the high frequency of influenza A and B in this population.

Outbreak of influenza A in a boarding school in South Africa, 2016

Introduction

We investigated an outbreak of influenza-like illness (ILI) at a boarding school in Eastern Cape Province, South Africa. We aimed to confirm the etiological agent, estimate attack rates and identify risk factors for illness.

Methods

We conducted a retrospective cohort study including senior school boarders (n=308). Students with ILI (cough and fever) were identified through school medical records. We also conducted a questionnaire-based cross-sectional study among senior students including boarders (n=107) and day students (n=45). We collected respiratory specimens for respiratory pathogen testing by real-time polymerase chain reaction from a subset of symptomatic students. We calculated attack rates of medically attended ILI (medILI) and identified factors associated with medILI using logistic regression. We calculated seasonal influenza vaccine effectiveness (VE) against medILI.

Results

Influenza A (H3N2) virus was detected in 61% (23/38) of specimens. Attack rate for medILI was 13% among boarders (39/308) in the cohort study and 20% in both day students (9/45) and boarders (21/107) in the cross-sectional study. Playing squash was associated with medILI (aOR 5.35, 95% confidence interval [95% CI]: 1.68-17.07). Of the boarders, 19% (57/308) were vaccinated before the outbreak. The adjusted VE against medILI was 18% (aOR 0.82, 95% CI 0.38-1.78). The outbreak led to cancellation of several events and the need for academic remedial sessions.

Conclusion

We confirmed an influenza A (H3N2) virus outbreak with a high attack rate. The outbreak affected academic and sports activities. Participation in sports and social gatherings while experiencing ILI should be discouraged to reduce viral transmission and impact on school activities.

Estimation of Burden of Influenza among under-Five Children in India: A Meta-Analysis

BACKGROUND

We estimated the burden of influenza-related acute respiratory tract infection (ARI) among under-fives in India through meta-analysis.

METHODOLOGY

We estimated pooled incidence and proportional positivity of laboratory-diagnosed influenza among under-fives using data from observational studies published from 1 January 1961 to 31 December 2016. Death due to influenza was estimated using a multiplier model.

RESULTS

Influenza-associated ARI incidence was estimated as 132 per 1000 child-years (115-149). The patients positive for influenza among ARI in outpatients and inpatients were estimated to be 11.2% (8.8-13.6) and 7.1% (5.5-8.8), respectively. We estimated total influenza cases during 2016 as 16 009 207 (13 942 916-18 082 769) in India. Influenza accounted for 10 913 476 (9 504 666-12 362 310) outpatient visits and 109 431 (83 882-134 980) hospitalizations. A total of 27 825 (21 382-34 408) influenza-associated under-five deaths were estimated in India in 2016.

CONCLUSION

Influenza imposes a substantial burden among under-fives in India. Public health approach for its prevention and control needs to be explored.

Estimating the annual attack rate of seasonal influenza among unvaccinated individuals: A systematic review and meta-analysis

INTRODUCTION

Seasonal influenza affects millions of people globally each year, causing significant morbidity and mortality. However, there remains substantial uncertainty about the attack rate (incidence) of influenza, particularly in unvaccinated individuals.

METHODS

We undertook a systematic review of vaccine randomised controlled trials (RCTs) that reported on laboratory-confirmed seasonal influenza in the placebo arm. We calculated the influenza attack rate from included studies as the number of laboratory-confirmed positive seasonal influenza cases in the placebo arm divided by the total number of subjects in this arm. A random effects meta-analysis was conducted to estimate the influenza attack rate among unvaccinated individuals (both symptomatic only as well as symptomatic and asymptomatic combined).

RESULTS

We included 32 RCTs that had a total of 13,329 participants. The pooled estimates for symptomatic influenza were 12.7% (95%CI 8.5%, 18.6%) for children (<18 years), 4.4% (95%CI 3.0%, 6.3%) for adults, and 7.2% (95%CI 4.3%, 12.0%) for older people (65 years and above). The pooled estimates for symptomatic and asymptomatic influenza combined for all influenza were 22.5% (95%CI 9.0%, 46.0%) for children and 10.7% (95%CI 4.5%, 23.2%) for adults. Only one study was identified for symptomatic and asymptomatic combined in older people which had a rate of 8.8% (95%CI 7.0%, 10.8%). There was substantial heterogeneity between studies.

CONCLUSION

Overall, we found that approximately 1 in 5 unvaccinated children and 1 in 10 unvaccinated adults were estimated to be infected by seasonal influenza annually, with rates of symptomatic influenza roughly half of these estimates. Our findings help to establish the background risk of seasonal influenza infection in unvaccinated individuals.

Influenza-associated outpatient visits among children less than 5 years of age in eastern China, 2011-2014

BACKGROUND

The disease burden of influenza in China has not been well described, especially among young children. The aim of this study was to estimate the incidence of outpatient visits associated with influenza in young children in Suzhou, a city of more than 11 million residents in Jiangsu Province in eastern China.

METHODS

Influenza-like illness (ILI) was defined as the presence of fever (axillary temperature ≥38 °C) and cough or sore throat. We collected throat swabs for children less than 5 years of age with ILI who visited Suzhou University Affiliated Children's Hospital (SCH) outpatient clinic or emergency room between April 2011 and March 2014. Suzhou CDC, a national influenza surveillance network laboratory, tested for influenza viruses by real-time reverse transcription-polymerase chain reaction assay (rRT-PCR). Influenza-associated ILI was defined as ILI with laboratory-confirmed influenza by rRT-PCR. To calculate the incidence of influenza-associated outpatient visits, we conducted community-based healthcare utilization surveys to determine the proportion of hospital catchment area residents who sought care at SCH.

RESULTS

The estimated incidence of influenza-associated ILI outpatient visits among children aged <5 years in the catchment area of Suzhou was, per 100 population, 17.4 (95 % CI 11.0-25.3) during April 2011-March 2012, 14.6 (95 % CI 5.2-26.2) during April 2012-March 2013 and 21.4 (95 % CI: 10.9-33.5) during April 2013-March 2014. The age-specific outpatient visit rates of influenza-associated ILI were 4.9, 21.1 and 21.2 per 100 children aged 0- <6 months, 6- <24 months and 24- <60 months, respectively.

CONCLUSION

Influenza virus infection causes a substantial burden of outpatient visits among young children in Suzhou, China. Targeted influenza prevention and control strategies for young children in Suzhou are needed to reduce influenza-associated outpatient visits in this age group.

Influenza A and Parvovirus B19 Seropositivity Rates in Gabonese Infants

Clinical and epidemiological data from Central Africa on influenza A and parvovirus B19 infections are limited. We analyzed 162 blood samples of infants 3, 9, 15, and 30 months of age for IgG antibodies against both pathogens. Antibody responses were 0, 3.7%, 12.3%, and 20.4% against influenza A; and 1.2%, 2.5%, 3.1%, and 9.3% against parvovirus B19, respectively. Seropositivity rates were 89.5 (95% confidence interval [CI]: 59-120.1) and 38.2 (95% CI: 18.9-57.6)/1,000 person-years at risk for influenza A and parvovirus B19, respectively. Our data add to the understanding of the epidemiology of both conditions.

Single, dual and multiple respiratory virus infections and risk of hospitalization and mortality

Respiratory virus infections cause a significant number of hospitalization and deaths globally. This study investigated the association between single and multiple respiratory virus infections and risk of admission to a general ward, intensive care unit or death in patients aged 0-105 years (mean ± s.d. = 24·4 ± 24·1 years), from North West England, that were tested for respiratory virus infections between January 2007 and June 2012. The majority of infections were in children aged ⩽5 years. Dual or multiple infections occurred in 10·4% (1214/11 715) of patients, whereas single infection occurred in 89·6% (10 501/11 715). Rhinovirus was the most common co-infecting virus (occurring in 69·5%; 844/1214 of co-infections). In a multivariate logistic regression model, multiple infections were associated with an increased risk of admission to a general ward [odds ratio (OR) 1·43, 95% confidence interval (CI) 1·2-1·7, P < 0·0001]. On the other hand, patients with respiratory syncytial virus (RSV) and human parainfluenza virus types 1-3 (hPIV1-3), as a single infection, had a higher risk of being admitted to a general ward (OR 1·49, 95% CI 1·28-1·73, P < 0·0001 and OR 1·34, 95% CI 1·003-1·8, P = 0·05, respectively); admitted to an intensive-care unit or dying (OR 1·5, 95% CI 1·20-2·0, P = 0·001 and OR 1·60, 95% CI 1·02-2·40, P = 0·04, respectively). This result emphasizes the importance of RSV, hPIV and mixed infections and calls for research on vaccines, drugs and diagnostic tests targeting these respiratory viruses.

The epidemiological impact of childhood influenza vaccination using live-attenuated influenza vaccine (LAIV) in Germany: predictions of a simulation study

Background

Routine annual influenza vaccination is primarily recommended for all persons aged 60 and above and for people with underlying chronic conditions in Germany. Other countries have already adopted additional childhood influenza immunisation programmes. The objective of this study is to determine the potential epidemiological impact of implementing paediatric influenza vaccination using intranasally administered live-attenuated influenza vaccine (LAIV) in Germany.

Methods

A deterministic age-structured model is used to simulate the population-level impact of different vaccination strategies on the transmission dynamics of seasonal influenza in Germany. In our base-case analysis, we estimate the effects of adding a LAIV-based immunisation programme targeting children 2 to 17 years of age to the existing influenza vaccination policy. The data used in the model is based on published evidence complemented by expert opinion.

Results

In our model, additional vaccination of children 2 to 17 years of age with LAIV leads to the prevention of 23.9 million influenza infections and nearly 16 million symptomatic influenza cases within 10 years. This reduction in burden of disease is not restricted to children. About one third of all adult cases can indirectly be prevented by LAIV immunisation of children.

Conclusions

Our results demonstrate that vaccinating children 2–17 years of age is likely associated with a significant reduction in the burden of paediatric influenza. Furthermore, annual routine childhood vaccination against seasonal influenza is expected to decrease the incidence of influenza among adults and older people due to indirect effects of herd protection. In summary, our model provides data supporting the introduction of a paediatric influenza immunisation programme in Germany.

The burden of seasonal and pandemic influenza in infants and children

The burden of influenza is unevenly distributed, with more severe outcomes in children aged <5 years than older children and adults. In spite of this, immunisation policies for young children are far from universal. This article provides an overview of the published evidence on the burden of influenza in children worldwide, with a particular interest in the impact of pandemic influenza in 2009-2010 (caused by the H1N1pdm09 virus). In an average season, up to 9.8 % of 0- to 14-year olds present with influenza, but incidence rates can be markedly higher in younger children. Children aged <5 years have greater rates of hospitalisation and complications than their older counterparts, particularly if the children have co-existing illnesses; historically, this age group have had higher mortality rates from the disease than other children, although during the 2009-2010 pandemic the median age of those who died of influenza was higher than in previous seasons. Admissions to hospital and emergency departments appear to have been more frequent in children with H1N1pdm09 infections than during previous seasonal epidemics, with pneumonia continuing to be a common complication in this setting. Outcomes in children hospitalised with severe disease also seem to have been worse for those infected with H1N1pdm09 viruses compared with seasonal viruses. Studies in children confirm that vaccination reduces the incidence of seasonal influenza and the associated burden, underlining the importance of targeting this group in national immunisation policies.

CONCLUSIONS

Children aged <5 years are especially vulnerable to influenza, particularly that caused by seasonal viruses, and vaccination in this group can be an effective strategy for reducing disease burden.

Estimating influenza incidence and rates of influenza-like illness in the outpatient setting

Please cite this paper as: Fowlkes et al. (2012) Estimating influenza incidence and rates of influenza‐like illness in the outpatient setting. Influenza and Other Respiratory Viruses DOI: 10.1111/irv.12014.

Background:  Estimating influenza incidence in outpatient settings is challenging. We used outpatient healthcare practice populations as a proxy to estimate community incidence of influenza‐like illness (ILI) and laboratory‐confirmed influenza‐associated ILI.

Methods:  From October 2009 to July 2010, 38 outpatient practices in seven jurisdictions conducted surveillance for ILI (fever with cough or sore throat for patients ≥2 years; fever with ≥1 respiratory symptom for patients <2 years). From a sample of patients with ILI, respiratory specimens were tested for influenza.

Results:  During the week of peak influenza activity (October 24, 2009), 13% of outpatient visits were for ILI and influenza was detected in 72% of specimens. For the 10‐month surveillance period, ILI and influenza‐associated ILI incidence were 20·0 (95% CI: 19·7, 20·4) and 8·7/1000 (95% CI: 8·2, 9·2) persons, respectively. Influenza‐associated ILI incidence was highest among children aged 2–17 years. Observed trends were highly correlated with national ILI and virologic surveillance.

Conclusions:  This is the first multistate surveillance system demonstrating the feasibility of using outpatient practices to estimate the incidence of medically attended influenza at the community level. Surveillance demonstrated the substantial burden of pandemic influenza in outpatient settings and especially in children aged 2–17 years. Observed trends were consistent with established syndromic and virologic systems.

George K, Hewlett IK, Linnen JM, Norris PJ. Sensitive detection assays for influenza RNA do not reveal viremia in US blood donors

BACKGROUND

There have been anecdotal reports of influenza viremia since the 1960s. We present an assessment of the prevalence of seasonal and 2009 H1N1 influenza viremia (via RNA testing) in blood donor populations using multiple sensitive detection assays.

METHODS

Several influenza RNA amplification assays, including transcription-mediated amplification (TMA) and 2 reverse-transcription polymerase chain reaction (RT-PCR) assays, were evaluated and used to test donor samples. Retrospective samples from 478 subjects drawn at sites with high influenza activity were tested. Prospective samples were collected from 1004 blood donors who called their donation center within 3 days of donation complaining of influenza-like illness (ILI). The plasma collected on the day of donation for these subjects was tested.

RESULTS

Of the repository samples, 2 of 478 plasma samples were initially reactive but not repeat reactive by influenza TMA. Of blood donors reporting ILI symptoms postdonation, 1 of 1004 samples was TMA initially reactive but not repeat reactive; all samples were nonreactive by RT-PCR testing.

CONCLUSIONS

Targeting blood donor populations most likely to have influenza infection, we failed to detect influenza RNA in 1482 donor samples, with most tested by 3 different RNA assays. Seasonal influenza does not appear to pose a significant contamination threat to the blood supply.

Global burden of respiratory infections due to seasonal influenza in young children: a systematic review and meta-analysis

BACKGROUND

The global burden of disease attributable to seasonal influenza virus in children is unknown. We aimed to estimate the global incidence of and mortality from lower respiratory infections associated with influenza in children younger than 5 years.

METHODS

We estimated the incidence of influenza episodes, influenza-associated acute lower respiratory infections (ALRI), and influenza-associated severe ALRI in children younger than 5 years, stratified by age, with data from a systematic review of studies published between Jan 1, 1995, and Oct 31, 2010, and 16 unpublished population-based studies. We applied these incidence estimates to global population estimates for 2008 to calculate estimates for that year. We estimated possible bounds for influenza-associated ALRI mortality by combining incidence estimates with case fatality ratios from hospital-based reports and identifying studies with population-based data for influenza seasonality and monthly ALRI mortality.

FINDINGS

We identified 43 suitable studies, with data for around 8 million children. We estimated that, in 2008, 90 million (95% CI 49-162 million) new cases of influenza (data from nine studies), 20 million (13-32 million) cases of influenza-associated ALRI (13% of all cases of paediatric ALRI; data from six studies), and 1 million (1-2 million) cases of influenza-associated severe ALRI (7% of cases of all severe paediatric ALRI; data from 39 studies) occurred worldwide in children younger than 5 years. We estimated there were 28,000-111,500 deaths in children younger than 5 years attributable to influenza-associated ALRI in 2008, with 99% of these deaths occurring in developing countries. Incidence and mortality varied substantially from year to year in any one setting.

INTERPRETATION

Influenza is a common pathogen identified in children with ALRI and results in a substantial burden on health services worldwide. Sufficient data to precisely estimate the role of influenza in childhood mortality from ALRI are not available.

FUNDING

WHO; Bill & Melinda Gates Foundation.

Long-lasting immunogenicity of a virosomal vaccine in older children and young adults with type I diabetes mellitus

To evaluate the long-lasting immunogenicity and reactogenicity of a virosomal influenza vaccine in subjects with type I diabetes, a trial was conducted during the 2007-2008 influenza season in Milan, Northern Italy. One hundred five subjects aged 9-30 years were randomized to receive by intramuscular injection vaccination by a single dose (0.5 ml) of either a virosomal (Inflexal V) (n=52) or a standard subunit (Influvac) (n=53) vaccine. Serum hemagglutinin inhibition antibody titres were determined against the three recommended influenza-like strains, A/H1N1, A/H3N2 and B, at pre-vaccination, and 1 and 6 months post-vaccination. Geometric mean titres were increased in the two groups 1 and 6 months post-vaccination (P<0.001). One month post-vaccination both vaccines met the CPMP requirement for immunogenicity with high seroprotection rates (>95%) for strains A/H1N1 and A/H3N2, and a seroprotection of 73% and 70% in the virosomal and subunit vaccine for strain B. Mean fold increase ranged 2.8 (A/H3N2)-6.2 (A/H1N1) in the virosomal group and 2.3 (A/H3N2)-4.8 (A/H1N1) in the subunit group. Immunogenicity declined 6 months post-vaccination in both groups, and the CPMP requirement for immunogenicity was satisfied only in the virosomal group. In subjects without pre-existing antibodies to strain B (titre <10), the virosomal vaccine showed higher immune response than the subunit vaccine 6 months post-vaccination, with a geometric mean titre (95% CI) of 40.2 (30.7-54.6) vs. 21.2 (14.6-30.8). Reactogenicity was similar in the two vaccines. All reactions were transient and not severe. The results indicate that in older children and young adults with type I diabetes influenza vaccination with a virosomal or a standard subunit vaccine is safe and adequately immunogenic against the three influenza vaccine strains. In addition, the virosomal vaccine may show better long-lasting immune response than the standard subunit vaccine, especially in subjects without pre-existing antibodies to influenza strains.

The Role of Influenza Vaccination in Asthmatic Children

Asthma is the most occurring chronic disease in children. Asthma related genes and environmental factors play a role in the etiology. Nowadays, asthma is regarded as a chronic inflammatory disease of the airways instead of solely a reversible airway obstruction. Asthma is often diagnosed on specific symptoms such as chest tightness, wheezing, dyspnea, and coughing. It is likely that, rather than a single disease entity, asthma consists of related, partially overlapping syndromes. The first symptoms often are experienced before the age of 5. Children with the highest risk have a family history of atopy and/or asthma. Viral infections with symptoms of wheezing acquired in the first year of life may be associated with the risk of developing asthma later on [1]. However, making the diagnosis with a reasonable certainty that is supported by spirometry is only possible from the age of 6 onward. More than 50% of children with a period of wheezing earlier on in life are not diagnosed as having asthma at the age of 6 [2].

The use of rescue and anti-inflammatory medication has largely altered the prospects of asthma patients and has improved their quality of life. Thus, nowadays, most asthma patients lead a normal life without restrictions. Disease control achieved by the asthmatics is an important predictor of the likelihood of complications of the disease [3]. However, asthma exacerbations neither respond to inhaled steroids nor can they substantially be prevented in this way [4, 5]. Only the use of oral corticos-teroids seems to be unmistakably effective in case of exacerbations [6, 7].

Excess drug prescriptions during influenza and RSV seasons in the Netherlands: potential implications for extended influenza vaccination

Influenza and respiratory syncytial virus (RSV) infections are responsible for considerable morbidity, mortality and health-care resource use. For the Netherlands, we estimated age and risk-group specific numbers of antibiotics, otologicals and cardiovascular prescriptions per 10,000 person-years during periods with elevated activity of influenza or RSV, and compared these with peri-season rates. Data were taken from the University of Groningen in-house prescription database (www.iadb.nl) and virological surveillance for the period 1998-2006. During influenza and RSV periods excess antibiotic prescriptions were estimated for all age groups. In the age groups 0-1 and 2-4 years, excess antibiotic prescriptions during periods with elevated RSV activity (65% and 59% of peri-seasonal rates) exceeded the surpluses estimated during the influenza-activity periods (24% and 34% of peri-seasonal rates) while for otologicals excess prescriptions were higher for influenza (22% and 27%) than for RSV (14% and 17%). Among persons of 50 years and older, notably those without medical high-risk conditions, excess prescriptions for cardiovascular medications were estimated during the influenza periods at approximately 10% (this was also already seen in persons aged 45-49). Our results may have implications for influenza vaccination policies. In particular, extension of influenza vaccination to groups of non-elderly adults and young children may lower excess prescriptions during these influenza periods for all three types of drug prescriptions investigated.

Economic burden and absenteeism from influenza-like illness in healthy households with children (5–17 years) in the US

BACKGROUND

School children (5-17 years) function as vectors in influenza epidemics. The objective of this study was to quantify the burden of influenza-like illness (ILI) on US healthy households with school-aged children.

METHODS

The Medical Expenditure Panel Survey database of 1996-2002 was queried to compare annual total medical expenses and absenteeism incurred by otherwise healthy households with school-aged children that reported experiencing ILI to similar households that did not experience ILI.

RESULTS

We identified 12,850 healthy households with at least one school-aged child. Households reporting one or more ILI episodes incurred $281.47 higher total annual medical expenses than those without an ILI. Employed members in households with ILI lost an average of 1.12 more workdays from their illness compared to those in the households without ILI. Furthermore, households with ILI in which all members were employed and medically insured lost an additional 0.89 workdays due to caring for other ill household members. School children in households with ILI missed 1.91 more school days annually and 4.87 more school days if the household had three or more students. The total annual additional cost to a household experiencing ILI, including medical expenses and productivity losses was $538.75 for fully employed and insured households and $424.83 if one or more members were unemployed or uninsured.

CONCLUSIONS

ILI increase economic burden among households with school-aged children and lead to more school and workdays lost. Initiatives to vaccinate school-aged children should be explored.

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

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

Influenza vaccination: policy versus evidence

Each year enormous effort goes into producing influenza vaccines for that specific year and delivering them to appropriate sections of the population. Is this effort justified?

Is influenza vaccination in asthmatic children helpful?

The rationale for influenza vaccination in asthmatic children theoretically lies in prevention of exacerbations and serious complications like pneumonia. Solid evidence from randomized clinical trials of its preventive effects on these clinical endpoints is, however, lacking. Nevertheless, most Western guidelines advise to vaccinate these children. In the real life situation this advice isn't very well followed: vaccine coverage for this indication is low. To assess the usefulness of influenza vaccination in children with asthma a set of fundamental questions regarding this activity is presented and answered. This leads to the conclusion that, given the evidence, influenza vaccination in children with mild to moderate disease should be reconsidered.