Long-acting neuraminidase inhibitor laninamivir octanoate (CS-8958) versus oseltamivir as treatment for children with influenza virus infection. Early oseltamivir treatment of influenza in children 1-3 years of age: a randomized controlled trial. Oral oseltamivir improves pulmonary function and reduces exacerbation frequency for influenza-infected children with asthma. Management of influenza in households: a prospective, randomized comparison of oseltamivir treatment with or without postexposure prophylaxis. Zanamivir for treatment of symptomatic influenza A and B infection in children five to twelve years of age: a randomized controlled trial. Efficacy of zanamivir for chemoprophylaxis of nursing home influenza outbreaks. Inhaled zanamivir versus rimantadine for the control of influenza in a highly vaccinated long-term care population. Rimantadine prophylaxis in children: a follow-up study. Safety, efficacy, and effectiveness of cold-adapted influenza vaccine-trivalent against community-acquired, culture-confirmed influenza in young children attending day care. Zanamivir prophylaxis: an effective strategy for the prevention of influenza types A and B within households. Evaluation of a neuraminidase-specific influenza A virus vaccine in children: antibody responses and effects on two successive outbreaks of natural infection.
We conducted a double-blind, randomized controlled trial to compare a long-acting neuraminidase inhibitor, laninamivir octanoate, with oseltamivir. Eligible patients were children 9 years of age and under who had febrile influenza symptoms of no more than 36-h duration. Patients were randomized to 1 of 3 treatment groups: a group given 40 mg laninamivir (40-mg group), a group given 20 mg laninamivir (20-mg group), and an oseltamivir group. Laninamivir octanoate was administered as a single inhalation. Oseltamivir (2 mg/kg of body weight) was administered orally twice daily for 5 days. The primary end point was the time to alleviation of influenza illness. The primary analysis included 184 patients (61, 61, and 62 in the 40-mg group, 20-mg group, and oseltamivir group, respectively). Laninamivir octanoate markedly reduced the median time to illness alleviation in comparison with oseltamivir in patients infected with oseltamivir-resistant influenza A (H1N1) virus, and the reductions were 60.9 h for the 40-mg group and 66.2 h for the 20-mg group. On the other hand, there were no significant differences in the times to alleviation of illness between the laninamivir groups and oseltamivir group for patients with influenza A (H3N2) or B virus infection. Laninamivir octanoate was well tolerated. The most common adverse events were gastrointestinal events. Laninamivir octanoate was an effective and well-tolerated treatment for children with oseltamivir-resistant influenza A (H1N1) virus infection. Further study will be needed to confirm clinical efficacy against influenza A (H3N2) or B virus infection. Its ease of administration is noteworthy, because a single inhalation is required during the course of illness. Oseltamivir provides modest clinical benefits to children with influenza when started within 48 hours of symptom onset. The effectiveness of oseltamivir could be substantially greater if the treatment were started earlier during the course of the illness.
                We carried out a randomized, double-blind, placebo-controlled trial of the efficacy of oseltamivir started within 24 hours of symptom onset in children 1-3 years of age with laboratory-confirmed influenza during the seasons of 2007-2008 and 2008-2009. Eligible children received either orally administered oseltamivir suspension or a matching placebo twice daily for 5 days. The children received clinical examinations, and the parents filled out detailed symptom diaries for 21 days.
                Of 408 randomized children who received the study drug (oseltamivir, 203, and placebo, 205), 98 had laboratory-confirmed influenza (influenza A, 79, and influenza B, 19). When started within 12 hours of the onset of symptoms, oseltamivir decreased the incidence of acute otitis media by 85% (95% confidence interval, 25%-97%), but no significant reduction was observed with treatment started within 24 hours. Among children with influenza A, oseltamivir treatment started within 24 hours shortened the median time to resolution of illness by 3.5 days (3.0 vs 6.5 days; P = .006) in all children and by 4.0 days (3.4 vs 7.3; P = .006) in unvaccinated children and reduced parental work absenteeism by 3.0 days. No efficacy was demonstrated against influenza B infections.
                Oseltamivir treatment started within 24 hours of symptom onset provides substantial benefits to children with influenza A infection. Clinical trials registration. ClinicalTrials.gov identifier: NCT00593502. Among asthmatic children, influenza is associated with increased hospitalizations. Although vaccination is safe and effective among asthmatic children, its protective efficacy varies and uptake rates can be low. In comparison, oseltamivir (Tamiflu) is effective against all influenza strains and can reduce the severity and duration of influenza among adults and children. This study determined the effects of oseltamivir among influenza-infected children with asthma.
                Asthmatic children (6-12 years of age) were randomized to receive oseltamivir (2 mg/kg) or placebo twice daily, as a syrup. The primary efficacy endpoint was the time to freedom from illness. Secondary endpoints included the area under the symptom score-hour curve, the proportion of patients with asthma exacerbations and changes in forced expiratory volume at 1 second during the dosing period. Analysis was performed for both the intent-to-treat infected (n = 179) and per protocol (n = 162) populations.
                The primary endpoint for this study was not met. Oseltamivir tended to reduce the time to freedom from illness in the intent-to-treat infected population (10.4 hours, 8%; P = 0.5420), the per protocol population (24.3 hours, 17%; P = 0.1607) and patients who started treatment <24 hours after symptom onset (39.8 hours, 25%; P = 0.0780). However, an improvement in pulmonary function was observed. The improvement in forced expiratory volume at 1 second was significantly greater among oseltamivir-treated patients (10.8% versus 4.7%; P = 0.0148). Oseltamivir-treated patients also experienced fewer asthma exacerbations up to day 7 (68% versus 51%; P = 0.031). Oseltamivir was safe and well-tolerated.
                Oseltamivir is safe and well-tolerated among asthmatic children, may reduce symptom duration and helps improve lung function and reduce asthma exacerbations during influenza infection. We determined the efficacy of postexposure prophylaxis (PEP) and treatment of ill index cases with oseltamivir, in an attempt to prevent influenza transmission in households, in a study conducted in 277 households with 298 index cases (62% with laboratory-confirmed influenza) and 812 contacts aged > or =1 year. Contacts were randomized by household to receive treatment (5 days; n=402), if illness developed, or PEP for 10 days (n=410), and the number of households with at least 1 contact developing laboratory-confirmed influenza was measured. PEP provided a protective efficacy of 58.5% (95% confidence interval [CI], 15.6%-79.6%; P=.0114) for households against proven influenza and 68.0% (95% CI, 34.9%-84.2%; P=.0017) for individual contacts, compared with treatment of index cases alone. No oseltamivir-resistant variants were detected in treated index cases or contacts. PEP of household contacts of those with influenza reduces the secondary spread of influenza in families when the initial household case is treated. Influenza infection rates are higher in children than in other age groups. This study evaluated the efficacy, safety and tolerability of a 5-day course of twice daily inhaled zanamivir, 10 mg, compared with placebo in the treatment of symptomatic influenza A and B viral infections among children 5 to 12 years of age.
                This double blind, randomized, placebo-controlled, parallel group, multicenter study conducted in the Northern Hemisphere during the 1998 and 1999 influenza season enrolled 471 patients with influenza-like symptoms for < or = 36 h. Patients were randomly assigned to zanamivir (n = 224) or placebo (n = 247). Symptoms were recorded on diary cards twice daily during treatment, for 9 days after treatment and for 14 additional days (if still reporting moderate/severe cough and/or taking relief medication).
                A total of 346 (73%) patients were influenza-positive by culture, serology or polymerase chain reaction (65% influenza A, 35% influenza B). Zanamivir reduced the median time to symptom alleviation by 1.25 days compared with placebo among patients with confirmed influenza infection (P < 0.001). Zanamivir-treated patients returned to normal activities significantly faster and took significantly fewer relief medications than placebo-treated patients. Zanamivir was well-tolerated, demonstrating adverse event profiles similar to those of placebo and no clinically significant changes in laboratory findings. Viral susceptibility testing revealed no zanamivir-resistant strains of influenza A or B.
                Zanamivir was effective in shortening the duration and severity of influenza symptoms and was well-tolerated among children 5 to 12 years of age. Despite vaccination, influenza remains a common of morbidity in nursing homes. Chemoprophylaxis of residents with currently available antivirals is not always effective and new agents effective against both influenza A and B are needed. In a randomized, unblinded pilot study, we compared 14 day chemoprophylaxis with zanamivir, an antiviral which inhibits influenza neuraminidase, to standard of care during sequential influenza A and influenza B outbreaks in a 735 bed nursing home. Influenza A outbreaks were declared on 6/14 epidemic units. Sixty-five volunteers on four epidemic units were randomized to zanamivir and on two epidemic units, 23 volunteers were randomized to rimantadine. During the 14 days of prophylaxis, only four new febrile respiratory illnesses were detected. One volunteer receiving rimantadine prophylaxis developed laboratory-confirmed influenza. Influenza B outbreaks were declared on 3/14 epidemic units. Thirty-five volunteers on two epidemic units were randomized to zanamivir and 18 volunteers on one epidemic unit were randomized to no drug. During the 14 days of prophylaxis, only one new febrile respiratory illness was detected. One volunteer randomized to receive no drug developed laboratory-confirmed influenza. Zanamivir appears comparably effective to standard of care in preventing influenza-like illness and laboratory-confirmed influenza in nursing homes, but requires further testing. Despite vaccination, influenza commonly causes morbidity and mortality in institutional settings. Influenza control with rimantadine and amantadine is limited by emergence and transmission of drug-resistant influenza A variants, ineffectiveness against influenza B, and toxicity. This study evaluated the efficacy and tolerability of zanamivir versus rimantadine for influenza outbreak control in long-term care facilities.
                This double-blind, randomized, controlled study prospectively enrolled nursing home residents for 3 influenza seasons (1997 to 2000). Vaccine was offered to all subjects. Following influenza outbreak declaration, subjects were randomized to inhaled zanamivir 10 mg or standard of care (rimantadine 100 mg for influenza A or placebo for influenza B) once daily for 14 days. The proportion of randomized subjects developing symptomatic, laboratory-confirmed influenza during prophylaxis was the primary endpoint.
                Of 482 randomizations (238 zanamivir, 231 rimantadine, 13 placebo), 96% of subjects were elderly or had high-risk conditions; over 90% were vaccinated. Symptomatic, laboratory-confirmed influenza occurred in 3% of zanamivir subjects and 8% of rimantadine subjects during chemoprophylaxis (P = .038; additional protective efficacy for zanamivir over rimantadine = 61%). Since only 25 subjects were randomized during 2 influenza B outbreaks and none developed influenza, the influenza B data were excluded from further analysis. Zanamivir was well tolerated and unassociated with emergence of resistant virus; rimantadine-resistant variants were common.
                This is the first prospective, controlled study demonstrating effectiveness of chemoprophylaxis for influenza outbreak control. Zanamivir prevents symptomatic, laboratory-confirmed influenza more effectively than rimantadine, is unassociated with resistant virus, and has a favorable safety profile. Zanamivir is an appropriate alternative for influenza outbreak control among institutionalized vaccinated elderly. In a randomized, double-blind placebo-controlled clinical trial, we evaluated the prophylactic effectiveness of rimantadine in children (ages 1 to 18 years) against infection with influenza A (H3N2) and associated illness and the prevention of transmission of infection to adult members of the child's family. One hundred ten volunteers from 29 families completed this study during a naturally occurring outbreak of influenza A (H3N2). Influenza infections, defined as a positive viral throat culture or a 4-fold increase in antibody titer, occurred in 31.0% of children in the placebo group and 7.4% in the rimantadine group (P = 0.026). Clinical illness with laboratory evidence of influenza infection occurred in 24.1% of children in the placebo group and none in the rimantadine group (P = 0.007). Rimantadine was well-tolerated by the children, with no significant difference in reported adverse effects between the placebo and rimantadine groups. A combined analysis by families of these data and those of our similarly designed 1984 study, revealed that families in whom the children were given rimantadine had a significantly lower rate of influenza A infection and influenza-like illness compared with the families in whom the children were given placebo (68.8% vs. 18.8%, P less than 0.001) and (56.3% vs. 12.5%, P less than 0.001), respectively. We conclude that rimantadine prophylaxis of children appears to be an effective method to prevent influenza A (either H1N1 or H3N2) infection and illness in children. The goal was to evaluate the safety, tolerability, and efficacy of an investigational, refrigerator-stable formulation of live attenuated influenza vaccine (cold-adapted influenza vaccine-trivalent) against culture-confirmed influenza, acute otitis media, and effectiveness outcomes in young children in day care over 2 consecutive influenza seasons.
                Children 6 to <36 months of age who were attending day care were assigned randomly in year 1 to receive 2 doses of vaccine or placebo intranasally, 35 +/- 7 days apart. In year 2, subjects received 1 dose of the same treatment as in year 1.
                A total of 1616 subjects (vaccine: 951 subjects; placebo: 665 subjects) in year 1 and 1090 subjects (vaccine: 640 subjects; placebo: 450 subjects) in year 2 were able to be evaluated for efficacy. The mean age at first vaccination was 23.4 +/- 7.9 months. In year 1, the overall efficacy of the vaccine against influenza subtypes similar to the vaccine was 85.4%; efficacy was 91.8% against A/H1N1 and 72.6% against B. In year 2, the overall efficacy was 88.7%; efficacy was 90.0% against H1N1, 90.3% against A/H3N2, and 81.7% against B. Efficacy against all episodes of acute otitis media associated with culture-confirmed influenza was 90.6% in year 1 and 97.0% in year 2. Runny nose or nasal discharge after dose 1 in year 1 was the only reactogenicity event that was significantly more frequent with cold-adapted influenza vaccine-trivalent (82.3%) than placebo (75.4%).
                Cold-adapted influenza vaccine-trivalent was well tolerated and effective in preventing culture-confirmed influenza illness in children as young as 6 months of age who attended day care. A double-blind, randomized study of inhaled zanamivir for the prevention of influenza in families was conducted. Once a person with a suspected case of influenza was identified (index patient), treatment of all other household members (contacts) > or =5 years old was initiated. Contacts received either 10 mg zanamivir or placebo inhaled once daily for 10 days. Index patients received relief medication only. In total, 487 households (242 placebo and 245 zanamivir) were enrolled, with 1291 contacts randomly assigned to receive prophylaxis. Four percent of zanamivir versus 19% of placebo households (P<.001) had at least 1 contact who developed symptomatic, laboratory-confirmed influenza, representing 81% protective efficacy (95% confidence interval, 64%-90%). Protective efficacy was similarly high for individuals (82%) and against both influenza types A and B (78% and 85%, respectively, for households). Zanamivir was well tolerated and was effective in preventing influenza types A and B within households where the index patient was not treated. Three groups of children were immunized with an inactivated Port Chalmers (H3ChN2Ch) influenza vaccine (group A), a neuraminidase-specific (Heq1N2Ch) influenza vaccine (group B), or a placebo. Immunization induced seroconversion for H3Ch and N2Ch-specific antibody in group A and for N2Ch antibody in group B. The protective efficacies observed against naturally acquired illness with the Port Chalmers strain of influneza A virus were 68.7% and 37.4% in groups A and B, respectively, in comparison to the placebo group, and those against illness produced by the subsequent outbreak of the Victoria strain were 80.0% and 72.7%. These data support the role of neuraminidase-specific immunization in protection against influenza. Although the degree of protection after vaccination with the Heq1N2Ch vaccine was less than that provided by the biphasic H3ChN2Ch vaccine against the Port Chalmers strain, it appeared to be similar in the two vaccine study groups against the Victoria strain.
Oseltamivir and zanamivir appear to have modest benefit in reducing duration of illness in children with influenza. However, our analysis was limited by small sample sizes and an inability to pool data from different studies. In addition, the inclusion of data from published trials only may have resulted in significant publication bias. Based on published trial data, oseltamivir reduces the incidence of acute otitis media in children aged one to five years but is associated with a significantly increased risk of vomiting. One study demonstrated that laninamivir octanoate was more effective than oseltamivir in shortening duration of illness in children with oseltamivir-resistant influenza A/H1N1. The benefit of oseltamivir and zanamivir in preventing the transmission of influenza in households is modest and based on weak evidence. However, the clinical efficacy of neuraminidase inhibitors in 'at risk' children is still uncertain. Larger high-quality trials are needed with sufficient power to determine the efficacy of neuraminidase inhibitors in preventing serious complications of influenza (such as pneumonia or hospital admission), particularly in 'at risk' groups.