Burden of influenza in healthy children and their households.

OBJECTIVE: A prospective, multicentre study was conducted to evaluate the burden of laboratory confirmed influenza in healthy children and their household contacts. METHODS: The patients were enrolled in four emergency departments (EDs) and by five primary care paediatricians (PCPs) in different Italian municipalities 2 days a week between November 1, 2001 and April 30, 2002. The study involved 3771 children less than 14 years of age with no chronic medical conditions who presented with a respiratory tract infection in EDs or PCP outpatient clinics during the study period. Nasopharyngeal swabs were collected for the isolation of influenza viruses and RNA detection. Information was also collected concerning respiratory illnesses and related morbidities among the study children and their household contacts. RESULTS: Influenza virus was demonstrated in 352 cases (9.3%). In comparison with the influenza negative children, those who were influenza positive had an older mean age, were more often attending day care centres or schools, more frequently experienced fever and croup, received more antipyretics, and had a longer duration of fever and school absence. Furthermore, their parents and siblings had more respiratory illnesses, received more antipyretics and antibiotics, needed more medical visits, missed more work or school days, and needed help at home to care for the ill children for a longer period of time. CONCLUSIONS: Influenza has a significant clinical and socioeconomic impact on healthy children and their families. Prevention strategies should also focus on healthy children regardless of their age because of their role in disease transmission.     

Against influenza in children, which actions?]

Each year, at any age, children are at risk of influenza illness during the epidemics. Children, especially those at school (attack rate close to 30%), have a major role in viral dissemination. Most of influenza illnesses occur in healthy children. Manifestations are typical, as in adults, in children over 5 years of age and less specific in younger children explaining misdiagnosis and underestimation in the youngest. Respiratory complications in outpatients include acute otitis media (close to 30% in children less than 3 years of age) and pulmonary disease (5 up to 10%). High fever 240 degrees C is frequent. Febrile convulsions occur in about 20% of hospitalised children aged 6 month to 5 years. Other complications (encephalitis, myositis, myocarditis, etc.) are reported. Hospitalisation rate is a severity index. In children less than 5 years of age, it is as high as 500/100,000 when risk factors exist and 100/100,000 when absent. Influenza, which is a respiratory virus, is the only one for which both a vaccine and specific treatment (anti-neuraminidases) exist. They are detailed.     

Recommendations for influenza immunization of children

Epidemiologic studies indicate that children of all ages with certain chronic conditions and otherwise healthy children younger than 24 months of age are hospitalized for influenza infection and its complications at high rates similar to those experienced by the elderly. Annual influenza immunization is recommended for all children with high-risk conditions who are 6 months of age and older. Young, healthy children are at high risk of hospitalization for influenza infection; therefore, the American Academy of Pediatrics recommends influenza immunization for healthy children 6 through 24 months of age, for household contacts and out-of-home caregivers of all children younger than 24 months of age, and for health care professionals. To protect these children more fully against the complications of influenza, increased efforts are needed to identify all high-risk children and inform their parents when annual immunization is due. The purposes of this statement are to update recommendations for routine use of influenza vaccine in children and to review the indications for use of trivalent inactivated influenza vaccine and live-attenuated influenza vaccine.     

Influenza vaccination among household contacts of children with cystic fibrosis and healthy children

BACKGROUND:

It is recommended that household contacts of children with cystic fibrosis and household contacts of children <2 years of age receive annual influenza vaccinations. There is little information documenting whether this recommendation is being followed.

METHODS:

A 20-question survey was distributed to caregivers of children with cystic fibrosis and to caregivers of healthy children <17 years of age seen in a Saskatoon (Saskatchewan) tertiary care centre. Survey questions addressed the influenza vaccination status of the child and household contacts. Respondents were also asked to rate the influence of various factors on the decision to vaccinate, using a 5-point Likert scale.

RESULTS:

Reported vaccination rates were 21%, 25% and 7% among household contacts of children with cystic fibrosis, children <2 years of age and children ≥2 years of age, respectively. Advice from their physician, belief that they were too healthy, and inconvenient times and locations of vaccination centres were significant influences when compared among the three groups. Other main deterrents to vaccination were belief that the vaccine does not prevent influenza and belief that its side effects are greater than its benefits.

CONCLUSION:

By understanding motivators and barriers to vaccination among household contacts of children with cystic fibrosis, effective strategies may be implemented to improve vaccination coverage against influenza. Strong recommendations by clinicians and improved access to vaccination centres are essential components in improving influenza vaccination coverage.     

Respiratory illness in preschool children with different forms of day care.

The incidence of respiratory tract disease was investigated in three groups of Swedish children: those in 14 day-care centers with 18 to 68 children each; those in home care (usually no siblings); and those in family day-care homes (average, four children). In family day-care homes a mother cared for her own and one to four other children during the day. A preliminary nine month study of 41 preschool children attending a day-care center and 41 comparable children in home care showed that children under 2 years of age in the center had more days with respiratory symptoms and more febrile illnesses (four per child) than those in home care (one per child). In a subsequent eight-month study of children under 2 years of age, children in day-care centers and home care were compared with children in family day-care homes. The 108 children in centers had more febrile illness (five per child) than the 57 children in home care (two per child), but the 42 children in family day-care homes had as many illnesses as those in day-care centers. The data suggest that increasing the number of contacts of an infant in day care beyond four to six children does not increase remarkably the incidence of respiratory tract disease.     

Accuracy and impact of a point-of-care rapid influenza test in young children with respiratory illnesses

OBJECTIVE: To determine whether a point-of-care rapid influenza test impacts the diagnostic evaluation and treatment of children with acute respiratory illnesses. DESIGN: Randomized controlled trial. SETTING: Pediatric emergency department and acute care clinic of a children's hospital. PARTICIPANTS: Children aged younger than 5 years with fever or acute respiratory symptoms during 2 influenza seasons (2002 through 2004). INTERVENTIONS: Surveillance days were randomized to performance or no performance of a point-of-care rapid influenza test. All children had a nasal and throat swab obtained for laboratory tests. The rapid test group had another nasal swab obtained for the QuickVue Influenza Test (Quidel Corp, San Diego, Calif), which was performed by nurses; results were shared immediately with treating physicians. MAIN OUTCOME MEASURES: Rapid test results were compared with results of the viral culture or 2 polymerase chain reaction assays for influenza. Diagnostic test ordering and antibiotic prescribing were compared for the groups. RESULTS: Of 468 enrolled children, 306 were from the emergency department and 162 from the clinic. Overall, 88 children (19%) had influenza infection. Of 205 children in the rapid test group, 51 (25%) had influenza infection. The rapid influenza test was 82% sensitive and 99% specific. In the emergency department, fewer children in the rapid test group had diagnostic tests ordered than in the no rapid test group (39% vs 51%, P = .03). There was no difference in test ordering in the clinic or in antibiotic prescribing in either setting. The use of antivirals was low. CONCLUSIONS: Point-of-care rapid influenza tests were sensitive and specific and were associated with less diagnostic testing in the emergency department.     

Prevention of influenza: recommendations for influenza immunization of children, 2006-2007

The purpose of this statement is to update recommendations for routine use of influenza vaccine in children for the 2006-2007 influenza season. The American Academy of Pediatrics recommends annual influenza immunization for (1) children with high-risk conditions who are 6 months and older; (2) healthy children 6 through 59 months of age; (3) household contacts and out-of-home caregivers of children with high-risk conditions and all healthy children younger than 5 years; and (4) health care professionals. Other children, adolescents, and adults can be immunized to decrease the impact of influenza as indicated in the Red Book: 2006 Report of the Committee on Infectious Diseases.     

Hospitalization attributable to influenza and other viral respiratory illnesses in Canadian children

BACKGROUND: We sought to estimate the incidence of hospitalization attributable to influenza virus infection in Canadian children while controlling for the impact of other respiratory viruses. METHODS: Hospital admissions for children and youth 0 to 19 years of age, 1994-2000, were modeled as a function of proxy variables for influenza, respiratory syncytial virus (RSV) and other respiratory viral activity, seasonality and trend, using a Poisson regression model with a linear link. These proxy variables were developed from influenza mortality and laboratory test results for influenza, RSV and other viruses. Various checks for consistency, model fit and robustness were conducted and guided model development. RESULTS: Overall, 1.5% of all pediatric respiratory admissions could be attributed to influenza (18 admissions per 100,000 per year). The largest burden was seen in infants 6 to 11 months of age with rates of 200 per 100,000 infants and approximately equivalent to the rate for adults aged 65 to 69. During peak influenza activity, 7% of respiratory admissions were attributable to influenza as were 35% of febrile seizure admissions. RSV and parainfluenza (PIV) were the major viral causes of hospital admission with rates of 130 and 160 per 100,000, respectively. Another 70 per 100,000 admissions were attributed to other influenza-like illnesses. CONCLUSIONS: Influenza is a significant cause of morbidity leading to hospitalization in Canadian children, particularly for those under 2 years of age. RSV, PIV and other respiratory viruses were found to be major causes of respiratory illness leading to hospital care, surpassing influenza.     

Prevention of influenza: recommendations for influenza immunization of children, 2007-2008

The American Academy of Pediatrics recommends annual influenza immunization for all children with high-risk conditions who are 6 months of age and older, for all healthy children ages 6 through 59 months, for all household contacts and out-of-home caregivers of children with high-risk conditions and of healthy children younger than 5 years, and for all health care professionals. To more fully protect against the morbidity and mortality of influenza, increased efforts are needed to identify and immunize all children at high risk and all healthy children ages 6 through 59 months and to inform their parents when annual immunizations are due. Previously unimmunized children who are at least 6 months of age but younger than 9 years should receive 2 doses of influenza vaccine, given 1 month apart, beginning as soon as possible on the basis of local availability during the influenza season. If children in this cohort received only 1 dose for the first time in the previous season, it is recommended that 2 doses be administered in the current season. This recommendation applies only to the influenza season that follows the first year that a child younger than 9 years receives influenza vaccine. A child who then also fails to receive 2 doses the next year should be given only 1 dose per year from that point on. Influenza vaccine should also continue to be offered throughout the influenza season, even after influenza activity has been documented in a community. On the basis of global surveillance of circulating virus strains, the influenza vaccine may change from year to year; indeed, 1 of the 3 strains in the 2007-2008 vaccine is different from the previous year's vaccine. All health care professionals, influenza campaign organizers, and public health agencies should develop plans for expanding outreach and infrastructure to immunize all children for whom influenza vaccine is recommended. Appropriate prioritization of administering influenza vaccine will also be necessary when vaccine supplies are delayed or limited. Because the influenza season often extends into March, immunization against influenza is recommended to continue through late winter and early spring. Lastly, it is recommended that for the 2007-2008 season, and likely beyond, health care professionals do not prescribe amantadine or rimantadine for influenza treatment or chemoprophylaxis, because widespread resistance to these antiviral medications now exists among influenza A viral strains. However, oseltamivir and zanamivir can be prescribed for treatment or chemoprophylaxis, because influenza A and B strains remain susceptible.     

The 1985 influenza epidemic in a pediatric practice

Because it is not possible to distinguish clinically influenza from other respiratory infections, virological methods have to be used to establish the influenza etiology. Nasopharyngeal swabs from 202 children with respiratory symptoms were taken. Influenza A virus (H3N2) was isolated from 44 children, influenza A virus (H1N1) from 61 children and influenza B virus from 13 children. The maximal activity of the two influenza A virus subtypes was different. The following features permitted the classification of 3 groups; monophasic fever greater than or equal to 38.5 degrees C (81.35%), biphasic fever (14.41%), and pseudocroup (4.24%). 16.1% of the children with fever also had gastrointestinal symptoms. No relation between influenza type/subtype and type of manifestation could be established.     

Influenza pneumonia

BACKGROUND: Influenza and pneumonia are common childhood illnesses, but few studies have been conducted on influenza-related pneumonia in children. The aim of this study was to describe the frequency and characteristics of laboratory-documented and radiologically detected influenza pneumonia in children. METHODS: This study involved children treated at the Department of Pediatrics, Turku University Hospital, from 1980 through 2003. Influenza A or B infection was documented with the use of antigen detection from nasopharyngeal aspirates. Children with chest radiographs obtained during influenza episodes were identified. Chest radiographs were reevaluated by a pediatric radiologist for verification of pneumonic infiltrates. Clinical and laboratory data were collected from medical records. RESULTS: Pneumonia was detected in 134 (14%) of 936 children with influenza infection. The most frequent signs of influenza pneumonia were fever and cough. Of these children, 47% had no specific clinical signs or symptoms suggesting pneumonia. White blood cell count was <15 x 10/L in 89% and serum C-reactive protein concentration <80 mg/L in 85% of the children. One-half of the children had solely interstitial infiltrates, one-fourth solely alveolar and one- fourth both alveolar and interstitial infiltrates on the chest radiograph. The hospitalization rate was 68%, and the median duration of hospitalization was 2 days. Complicated pneumonias were rare, and mortality was low (0.7%). CONCLUSIONS: Pneumonia is detected in a minority of children treated for influenza at a tertiary center. Unlike in adults, influenza pneumonia in children is usually a benign illness, and the mortality is low.     

Reduction of the influenza burden in children

Epidemiologic studies indicate that children with certain chronic conditions, such as asthma, and otherwise healthy children younger than 24 months are hospitalized for influenza and its complications at high rates similar to those experienced by the elderly. Currently, annual influenza immunization is recommended for all children 6 months and older with high-risk conditions. To protect these children more fully against the complications of influenza, increased efforts are needed to identify and recall high-risk children for annual influenza immunization. In addition, immunization of children 6 through 23 months of age and their household contacts and out-of-home caregivers is now encouraged to the extent feasible. The ultimate goal is a universal recommendation for influenza immunization. Issues that need to be addressed before institution of routine immunization of healthy young children include education of physicians and parents about the morbidity caused by influenza, adequate vaccine supply, and appropriate reimbursement of practitioners for influenza immunization.     

Illness among schoolchildren during influenza season: effect on school absenteeism,parental absenteeism from work,and secondary illness in families

BACKGROUND: High attack rates of Influenzavirus among school-aged children tend to be expected to cause significant disruption of usual activities at school and at home. OBJECTIVE: To quantify the effect of influenza season on illness episodes, school absenteeism, medication use, parental absenteeism from work, and the occurrence of secondary illness in families among a cohort of children enrolled in an elementary school during the 2000-2001 influenza season. DESIGN: Prospective survey study. SETTING: Kindergarten through eighth grade elementary school in Seattle, Wash. PATIENTS OR OTHER PARTICIPANTS: All children enrolled in the school were eligible for the study. Study participants were 313 children in 216 families. MAIN OUTCOME MEASURES: The primary outcome measure was missed school days. Secondary outcomes measures included total illness episodes, febrile illness episodes, medication usage, physician visits, parental workdays missed, and secondary illnesses among family members of children in the study cohort. Differences between the rates of study events among participants when influenza was circulating and the event rates during the winter season when influenza was not circulating were used to calculate influenza-attributable excess events. RESULTS: Total illness episodes, febrile illness episodes, analgesic use, school absenteeism, parental industrial absenteeism, and secondary illness among family members were significantly higher during influenza season compared with the noninfluenza winter season. For every 100 children followed up for this influenza season, which included 37 school days, an excess 28 illness episodes and 63 missed school days occurred. Similarly, for every 100 children followed up, influenza accounted for an estimated 20 days of work missed by the parents and 22 secondary illness episodes among family members. CONCLUSION: Influenza season has significant adverse effects on the quality of life of school-aged children and their families.     

Technical report: Reduction of the influenza burden in children

Epidemiologic studies have shown that children of all ages with certain chronic conditions, such as asthma, and otherwise healthy children younger than 24 months (6 through 23 months) are hospitalized for influenza and its complications at high rates similar to those experienced by the elderly. Annual influenza immunization is already recommended for all children 6 months and older with high-risk conditions. By contrast, influenza immunization has not been recommended for healthy young children. To protect children against the complications of influenza, increased efforts are needed to identify and recall high-risk children. In addition, immunization of children between 6 through 23 months of age and their close contacts is now encouraged to the extent feasible. Children younger than 6 months may be protected by immunization of their household contacts and out-of-home caregivers. The ultimate goal is universal immunization of children 6 to 24 months of age. Issues that need to be addressed before institution of routine immunization of healthy young children include education of physicians and parents about the morbidity caused by influenza, adequate vaccine supply, and appropriate reimbursement of practitioners for influenza immunization. This report contains a summary of the influenza virus, protective immunity, disease burden in children, diagnosis, vaccines, and antiviral agents.     

The burden of influenza in children under 5 years admitted to the Children's Hospital at Westmead in the winter of 2006

Objective: Active surveillance to determine influenza disease burden in children admitted to hospital with influenza‐like illness (ILI). Methods: A prospective hospital‐based cohort study conducted June–October 2006 in children <5 years hospitalised at The Children's Hospital at Westmead with ILI (fever and respiratory symptoms). Influenza and other viral infections were diagnosed either by antigen detection using immunofluorescence or nucleic acid amplification testing of nasopharyngeal aspirates. Data were collected using researcher‐administered questionnaires. Main outcome measures include proportion of hospitalisations with influenza, vaccination and treatment, risk factors for influenza and associated medical and social burdens. Results: Data on 275 children with ILI aged <5 years were analysed. Thirty‐one (11%) children with ILI had influenza (22 had influenza A and 9 had influenza B). Thirty‐five percent were under 6 months of age and 61% under 1 year. Twenty‐nine percent of children with influenza A were born prematurely. The mean duration of hospital stay for influenza was 2.8 days (95% confidence interval 2.1–3.4) and 26% had a lumbar puncture. Although 68% received intravenous antibiotics, only 3% (one case) was given an antiviral. Eighty‐four percent had visited their local doctor before admission and all came through the emergency department. On average, in one‐third (32%) of families of children with influenza a parent developed, ILI during admission or soon after hospital discharge resulted in an average of 3.2 days of work absenteeism. Only 3.5% (7/199) of children older than 6 months with ILI received any influenza vaccination. Conclusions: Both the burden of influenza in childhood morbidity and its social impact are substantial. There is considerable room for improvement in both the prevention and early recognition (trigger treatment with antivirals) of influenza. Our data will inform decisions regarding the value of a universal influenza vaccine programme.