***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVE To compare the effectiveness of zanamivir with oseltamivir for influenza A and B. METHODS 1113 patients with influenza A or B were enrolled in the 2006 - 2007 influenza season . The duration of fever ( temperature , > or=37.5 degrees C ) and the percentage of patients afebrile at 24 and 48 h after the first dose of zanamivir or oseltamivir  were calculated . Virus persistence after zanamivir therapy was also evaluated . RESULTS There were marginally significant differences between the duration of fever after the first dose of zanamivir ( 31.8+/-18.4h ) and oseltamivir ( 35.5+/-23.9h ) for influenza A ( p<0.05 ) . The duration of fever after starting zanamivir therapy ( 35.8+/-22.4h ) was significantly shorter than that of oseltamivir ( 52.7+/-31.3h ) for influenza B ( p<0.001 ) . There were no significant differences between influenza A and B in the percentage of patients afebrile at 24 or 48 h after the first inhalation of zanamivir . The reisolation rate after zanamivir  therapy showed marginally significant differences between influenza A and B ( < 0.05 ) . By multiple regression analysis , therapy ( zanamivir or oseltamivir ) was the major determinant affecting the duration of fever for influenza B. CONCLUSION Zanamivir therapy is more effective than oseltamivir for the treatment of influenza B infection Background —Influenza infection has been associated with increased risk of adverse cardiac and cerebral vascular outcomes .  Oseltamivir , a treatment for influenza , has been shown to decrease the severity of an influenza episode , but few data exist regarding its potentially protective effect against recurrent vascular outcomes among influenza patients with a history of vascular disease . Methods and Results —Electronic healthcare service and pharmacy records for 37 482 TRICARE beneficiaries , aged 18 and older , with a coded history of cardiovascular ( CV ) disease and a subsequent diagnosis of influenza from October 1 , 2003 , through September 30 , 2007 , were examined . Subjects were grouped according to whether they had filled a prescription for oseltamivir within 2 days of their influenza diagnosis . The incidence of recurrent CV events within 30 days after the influenza diagnosis among oseltavmivir-treated and untreated subjects was 8.5 % and 21.2 % , respectively ( P<0.005 ) . Subject age was a persistent and significant contributor to the likelihood of recurrent CV outcomes . After controlling for the differences in demographics among treated and untreated cohorts using a propensity-scored logistic regression model , a statistically significant protective effect was associated with oseltamivir treatment ( odds ratio , 0.417 ; 95 % CI , 0.349 to 0.498 ) . Conclusions —Our findings suggests that oseltamivir treatment for influenza is associated with significant decrease in the risk of recurrent CV events in subjects with a history of CV disease . These findings merit confirmation in further prospect i ve and controlled studies . Meanwhile , in patients with CV disease , strict adherence with current practice guidelines for prevention and treatment of influenza is recommended Background The aim of this study was to investigate factors affecting clinical outcomes of adults hospitalised with severe seasonal influenza . Methods A prospect i ve , observational cohort study was conducted over 24 months ( 2007–2008 ) in two acute , general hospitals . Consecutive , hospitalised adult patients were recruited and followed once their laboratory diagnosis of influenza A/B was established ( based on viral antigen detection and virus isolation from nasopharyngeal aspirates collected per protocol ) . Outcomes studied included in-hospital death , length of stay and duration of oxygen therapy . Factors affecting outcomes were analysed using multivariate Cox proportional hazards models . Sequencing analysis on the neuraminidase gene was performed for available H1N1 isolates . Results 754 patients were studied ( influenza A , n=539 ; > 75 % H3N2 ) . Their mean age was 70±18 years ; co-morbidities and serious complications were common ( 61–77 % ) . Supplemental oxygen and ventilatory support was required in 401 ( 53.2 % ) and 41 ( 5.4 % ) patients , respectively . 39 ( 5.2 % ) patients died ; pneumonia , respiratory failure and sepsis were the causes . 395 ( 52 % ) patients received antiviral ( oseltamivir ) treatment . Omission of antiviral treatment was associated with delayed presentation or negative antigen detection results . The mortality rate was 4.56 and 7.42 per 1000 patient-days in the treated and untreated patients , respectively ; among those with co-morbidities , it was 5.62 and 11.64 per 1000 patient-days , respectively . In multivariate analysis , antiviral use was associated with reduced risk of death ( adjusted HR ( aHR ) 0.27 ( 95 % CI 0.13 to 0.55 ) ; p<0.001 ) . Improved survival was observed with treatment started within 4 days from onset . Earlier hospital discharge ( aHR 1.28 ( 95 % CI 1.04 to 1.57 ) ; p=0.019 ) and faster discontinuation of oxygen therapy ( aHR 1.30 ( 95 % CI 1.01 to 1.69 ) ; p=0.043 ) was associated with early treatment within 2 days . Few ( n=15 ) H1N1 isolates in this cohort had the H275Y mutation . Conclusions Antiviral treatment for severe influenza is associated with reduced mortality and improved clinical outcomes Oseltamivir has been used for treatment of influenza A and B infections , but recent reports documented that it was less active against the latter . We compared the effectiveness of oseltamivir in children between laboratory confirmed influenza A and B over 4 influenza seasons from 2001 to 2005 in a pediatric clinic in Japan . Among 1,848 patients screened , 299 influenza A and 209 influenza B patients were administered oseltamivir  ( treated groups ) , and 28 influenza A and 66 influenza B patients were assigned as non-treated groups . The duration of fever , defined as period when patients had the maximum temperature higher than 37.5 degrees C in three-time measurements in a day after the clinic visit , was evaluated among the four groups . In uni-variate analysis , the duration of fever was shorter for treated group than non-treated for influenza A ( 1.8 + /- 0.9 days vs 2.6 + /- 1.3 days , p < 0.01 ) , but it was not significant for influenza B ( 2.4 + /- 1.3 days vs 2.8 + /- 1.2 days , p = 0.9 ) . The fever duration was longer in treated influenza B than A patients ( p < 0.01 ) . Multi-variate analysis indicated younger age ( < 6 years old ) and higher body temperature at the clinic visit prolonged the duration of fever . Adjusted average duration of fever indicated that oseltamivir was effective for both types , but more effective on influenza A , and the benefit increased for younger children . Our data provide evidence that oseltamivir is beneficial for influenza infections , but the effectiveness is differed by type and age BACKGROUND To compare the effectiveness of oseltamivir for treatment of influenza A and influenza B , we conducted a prospect i ve , multicenter study of the 2003 - 2004 and 2004 - 2005 influenza seasons . The study included 3351 patients in whom influenza had been diagnosed by use of an antigen detection test kit . METHODS Oseltamivir was administered to 1818 patients with influenza A and 1485 patients with influenza B. No anti-influenza drugs were administered to 21 patients with influenza A or to 27 patients with influenza B. Patients receiving oseltamivir therapy were divided into 4 groups according to the time between the onset of fever ( temperature , > or = 37.5 degrees C ) and administration of the first dose of oseltamivir ( 0 - 12 h , 13 - 24 h , 25 - 36 h , and 37 - 48 h ) . The patients were also divided into 4 subgroups on the basis of age ( 0 - 6 years , 7 - 15 years , 16 - 64 years , and > 64 years ) . Virus isolation was performed after completion of oseltamivir therapy for 44 patients with influenza A and 31 patients with influenza B. RESULTS The duration of fever was significantly shorter for patients with influenza A and B who were treated with oseltamivir than for patients who were not treated with an anti-influenza drug ( P<.001 for both ) . The time until the patient became afebrile after the initial administration of oseltamivir and the duration of fever were significantly longer for patients with influenza B than for patients with influenza A for the 0 - 12 h , 13 - 24 h , 25 - 36 h , and 37 - 48 h groups ( P<.001 ) and for all age groups ( P<.001 ) . After 4 - 6 days of oseltamivir therapy , the influenza B virus reisolation rate ( 51.6 % ) was significantly higher than the influenza A virus reisolation rate ( 15.9 % ) ( P<.001 ) . CONCLUSION Oseltamivir is less effective for influenza B than for influenza A with regard to duration of fever and virus persistence , irrespective of patient age or the timing of administration of the first dose Summary : Respiratory viruses ( RVs ) frequently cause severe respiratory disease in bone marrrow transplant ( BMT ) recipients . To evaluate the frequency of RV , nasal washes were collected year-round from BMT recipients with symptoms of upper respiratory tract infection ( URI ) . Direct immunofluorescence assay was performed for respiratory syncytial virus ( RSV ) , influenza ( Flu ) A and B , adenovirus and parainfluenza ( Paraflu ) virus . Patients with RSV pneumonia or with upper RSV infection , but considered at high risk for developing RSV pneumonia received aerosolized ribavirin . Oseltamivir was given to patients with influenza . A total of 179 patients had 392 episodes of URI . In all , 68 ( 38 % ) tested positive : RSV was detected in 18 patients ( 26.4 % ) , Flu B in 17 ( 25 % ) , Flu A in 11 ( 16.2 % ) and Paraflu in 7 ( 10.3 % ) . A total of 14 patients ( 20.6 % ) had multiple RV infections or coinfection . RSV pneumonia developed in 55.5 % of the patients with RSV-URI . One of the 15 patients ( 6.6 % ) with RSV pneumonia died . Influenza pneumonia was diagnosed in three patients ( 7.3 % ) . RSV and influenza infections peaked in fall – winter and winter – spring months , respectively . We observed decreased rates of influenza and parainfluenza pneumonia and low mortality because of RSV pneumonia . The role of antiviral interventions such as aerosolized ribavirin and new neuraminidase inhibitors remains to be defined in r and omized trials Abstract Background The goal of this study was to characterize viral loads and factors affecting viral clearance in persons with severe influenza Methods This was a 1-year prospect i ve , observational study involving consecutive adults hospitalized with influenza . Nasal and throat swabs were collected at presentation , then daily until 1 week after symptom onset . Real-time reverse-transcriptase polymerase chain reaction to determine viral RNA concentration and virus isolation were performed . Viral RNA concentration was analyzed using multiple linear or logistic regressions or mixed-effect models Results One hundred forty-seven in patients with influenza A ( H3N2 ) infection were studied ( mean age ± st and ard deviation , 72±16 years ) . Viral RNA concentration at presentation positively correlated with symptom scores and was significantly higher than that among time-matched out patients ( control subjects ) . Patients with major comorbidities had high viral RNA concentration even when presenting > 2 days after symptom onset ( mean ± st and ard deviation , 5.06±1.85 vs 3.62±2.13 log10 copies/mL ; P=.005 ; β , + 0.86 [ 95 % confidence interval , + 0.03 to + 1.68 ] ) . Viral RNA concentration demonstrated a nonlinear decrease with time ; 26 % of oseltamivir-treated and 57 % of untreated patients had RNA detected at 1 week after symptom onset . Oseltamivir started on or before symptom day 4 was independently associated with an accelerated decrease in viral RNA concentration ( mean β [ st and ard error ] , −1.19 [ 0.43 ] and −0.68 [ 0.33 ] log10 copies/mL for patients treated on day 1 and days 2–3 , respectively ; P<.05 ) and viral RNA clearance at 1 week ( odds ratio , 0.10 [ 95 % confidence interval , 0. 
    Output:
    
From these observational studies , the summary estimates suggest that oseltamivir may reduce mortality , hospitalisation and duration of symptoms compared with no treatment .
Inhaled zanamivir may also reduce symptom duration and hospitalisations , but patients may experience more complications compared with no treatment .
Earlier treatment with antivirals is generally associated with better outcomes than later treatment .